Engineering portfolio

Anup PoddaturiMechanical Engineering Portfolio

Arizona State UniversityMaster of Science

[email protected]@asu.edu

+1-480-519-0022

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mailto:[email protected]

mailto:[email protected]

S.No TITLE PAGE NUMBER1. Introduction & about me 32. Product Design Intern 43. Design Engineer 74. Product Development Intern 95. Structural assessment and analysis of thrust vector control (tvc) hydraulic system flight filter manifold 106. Design of aircraft fuselage 167. Modeling of Robots 188. Study of thermal storage from the exhaust of a diesel engine 229. Experimental and analytical studies of heat transfer from a pin fin in transitional flow regime 2610. Simulation of Hele-Shaw Flow 3611. Optimization of wind turbine system 3712. Vehicle Engineer 40

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CONTENTS

IntroductionWelcome, and thank you for taking the time to view my portfolio. My name is Anup Poddaturi. I am currently a graduate student studying Mechanical Engineering at Arizona State University, majoring in Finite Elements, Solid Mechanics and Design. The Goal of this portfolio is to give you a deeper insight into my professional and academic experiences and skills I have gained over the course of my Engineering study. My undergraduate study was in Mechanical Engineering, where I gained exposure on the basic Mechanical Engineering courses and I did my Master’s in Mechanical Engineering, specializing in Finite Elements, Design and Solid Mechanics. Throughout my years in college and graduate school, I have worked extensively on various projects in different fields, both in industry and research settings; which helped develop a diverse skillset in Mechanical Engineering, Finite Elements, CAE Analysis, Solid Mechanics, Reverse Engineering, Product Development, Product Design, Design Optimization, Polymer and Composite Materials, Fluid Mechanics, Robotics and computer programming. It is my hope that this portfolio will allow you to better assess how my skills can be applied to your company. I would be happy to talk in more detail and can be reached using the contact information on the first page. Thanks for your valuable time spent in looking at my profile.

About MeObjective: Seeking for the position as a Design Engineer/CAE Analysis Engineer within an organization that progresses dynamically and provides me an opportunity to enhance my skills and update my knowledge, assume positions of leadership and responsibility within an organization; and progress through advanced degree or certificate programs in engineering, business, and other professionally related fields.

Performance delivering design engineer, passionate about designing, proficient in CAD modeling, Analysis, Reverse Engineering, 3D Printing, Product Design and Product Development with 1.5 years of experience in Product Design and Analysis of High, Medium and Low Electro-Mechanical components using Creo and ANSYS as Product Design Intern at TE Connectivity, North Carolina. Also 1 year of Work experience in designing single stage or progressive stage dies for stamping, forming, forging, or extrusion presses, as per product blueprints as Design Engineer at Varad Extrusions Private Limited, India. Demonstrated ability to work as a team/individual in multiple deadline bound projects. I am driven by the desire to gain knowledge and work hard to achieve the desired goals. Available for relocation. I am currently on F1 Visa status and will be working on Post-OPT after the completion of my graduation. Expected graduation date is May 2016.

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INTRODUCTION & ABOUT ME

TE Connectivity

I Worked as Product Design Engineering Intern in Research, Engineering and Advanced Technology (READ) department at TE Connectivity, Fuquay Varina, North Carolina for a period of 12 weeks. My responsibilities include designing and validating High, Medium & Low metal and plastic electro-mechanical components using Creo. Analysis and validation of the components using ANSYS, which include Structural and Thermal Analysis. Designing fixtures for cables, validating them using Instron tensile testing machine. Prototyping using Makerbot 3D Printer. Data management on the TE cloud using PDM Windchill. Reporting to the manager regarding the status of the project.Modelling and Drawing of the HMV components which includes:Modelling, Analysis and Physical testing of Clamps according to IEC 61914 Standard.Raysulate Cover & Bus bars : Modelling and drawing Insulating boots for 4 KV bus bar connections.Cheese Grater : Modelling and drawing Grounding straps for termination and joints.Surge Arrester : Modelling and drawing Arrester hot line clamps and Support bolted connector for transmission line arrester.WMATA : Heat shrink boot fixture and product design.Mining coupler : Insulator Drawings.Drawing, drafting, BOM and GD&T and other tasks as required.

May 2015 – August 2015

Product Design Intern May 2015 – August 2015

Surge Arrester for transmission line arrester

Insulating boots

Heat shrink product design

Cheese grater

Mining coupler

Clamp and Fixture Design

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Projects:1) Modeling, Analysis and Testing of high voltage cable clamps according to IEC standard 61914.• Metallic clamps and polymer clamps.• Modeled polymer clamps for cable sizes of 18 - 130 mm and

metallic clamps for cable sizes of 50 – 155 mm.This was a improvement to the existing product and was supposed to be launched with new design. Designed the clamps using Creo. Performed analysis on the clamps according to IEC 61914 standard, based on these results fixture was designed. ANSYS Analysis was carried out and physical testing was done on the clamp-fixture setup using INSTRON tensile testing machine.


2) Design of Hand truck Hitch to connect Electric mover and HV termination setup.Design and Analysis of Hand truck hitch design, responsible for the project from its initial design until validation. The project was considered to aid the R&D team in moving heavy weighed High voltage termination setup from one place to other. Different designs for the hand truck hitch were considered and modeled. Analysis were carried out on all the design models and the best design was selected for manufacturing. Achieved a cost savings of $5000 working on this project.



5Hand truck Hitch DesignFigure showing Clamp and fixture

3) Design and Analysis of OHVT setup

Objective: To Analyze the thermal profile of the high voltage XLPE cable which is supposed to be used inside Oil Filled High Voltage Termination (OHVT). The cable has layers of Copper Conductor, Semi-Conductive tape, Conductor Shield, Super clean XLPE Insulation, Insulation Shield, Water Swell able, Semi-Conductive tape, AWG Concentric wires, Jacket and Semi-Conductive Jacket layer. Modeled the high voltage cable using Creo 2.0. Performed Thermal Analysis on the cable using Ansys Workbench 15.0. Total cost saving of 15000 USD.


4) Designing Auto bagger chute using Makerbot 3D PrinterObjective: Design the auto bagger chute to get rid of manual packaging, thereby aiding the packaging team. Cross functional work with other manufacturing intern.

• Designed using Creo.• Prototyped using Makerbot 3D Printer made from Acrylonitrile butadiene styrene (ABS).•Worked with different 3D printing materials like Acrylonitrile butadiene styrene (ABS), High Impact Polystyrene (HPS), Polylactic Acid (PLA), Polyvinyl Alcohol (PVA), Soft Polylactic Acid (Soft PLA), PLA 404 3D.•Studied the effect of material type, tool speed and tool path on the quality of the print.


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Figures showing the parts and assembly of OHVT termination setupAuto bagger chute made from 3D printer

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2D Drawings were created using Creo. Also Bill of materials (BOM), tolerancing and dimensioning were also created. Design change orders and engineering change orders were taken care of. Design change history was also mentioned in the 2D drawing. Some of them are shown below.


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Varad Extrusions Private Limited Overview: Worked as Design Engineer in the Engineering department of the company. Designed Progressive Dies, implemented improvements, cost reduction projects and worked with vendors on tooling related issues, quoted some tooling. Etc. Developed plans for single stage or progressive stage dies for stamping, forming, forging, or extrusion presses, as per product blueprints using Creo/ProEngineer. Testing & validation of the extruded components using Ansys. Worked with inter-disciplinary teams involving design, manufacturing, quality & sales in each phase of the product development life cycle from concept, design, testing and validation to implementation, packaging and marketing.My responsibilities include:Handling Spectro Machine Reports: This is a machine used for testing the propositions of the aluminum alloy (% of aluminum, Fe-Iron, Mn-Manganese, Mg-Magnesium, Si-Silicon) from the samples taken from each batch of melting process. This machine is maintained in specific conditions and with utmost care... It costs around 3 million INR and its annual maintenance is around 0.1 million INR.Inspection on the genuinity of the spares:All the machines require new spares very frequently due to heavy wear and tear. My responsibility was to particulate spare and its specific use (Heavy/Light) for the correct item to be procured.Handling the external Mechanics:Handling the technical issues relating to Cranes, Packing machine, Spectro machine, Electrical Panel boards, hot top casting system, and talking to the technical team in case of any technical issue. Not to be fooled due to unawareness.

DESIGN ENGINEER JUNE 2013 – JULY 2014

Procuring Spares Internationally:As most of the machines are procured from Italy, China, Bangkok and Singapore. Due to the wear and tear, we need to order new spares like Transducers, heavy valves, liners, containers, compatible switches etc. which are needed to be technically studied (Dimensions, purpose, size, code etc.) and order the right parts by coordinating with the technical team abroad.Inventory Management of Spares:All the existing spares need to be technically analyzed and maintained in spare as the production need to be supported without a break as it runs in a 24 hr. shift. Right part to be handed over when internal technical team asks for to make issues resolved. Manufacturing Intern Worked as Manufacturing Intern during the Summer of 2011. Assisted with various cross-functional projects within the manufacturing plant. Obtained a general understanding of each department: Plant Engineering, Manufacturing, Quality, Maintenance, Warehouse, and Distribution.General understanding of different manufacturing process like welding, forging, drilling, extrusion and castingAssisted in plant Quality Audits, 5S, and other process improvement areas.

HMT Limited

Overview:Worked as Product Development Intern in the Engineering department at the Hyderabad campus for three months. The Internship was a part of my undergraduate degree. I was solely responsible in the project from the design conception to the final validation. The press frame is a basic element of the press, aiming to support all of the machine kinematics and force transmission from the press to the workpiece. The model of the complex structure analyzed, completed and prepared as shown. For FEA analysis, either static or dynamic, ProMechanica is used. Followed the phases: defining the mesh, defining the environment bonds, defining the loads, performing analysis and result interpretation.Defining the Mesh: The mode of obtaining the mesh was presented before. The mesh has 17857 nodes, 30875 finite elements, element type SHELL 3 for discretization of all bed plates and type TETRA 4 for discretization of cantilevers and the bosses. Different designs of Press bed were considered before modeling the actual one. Modeling of the press bed was done using ProEngineer Wildfire. The Analysis was carried out using Ansys. Also studied the advantages of the hydraulic press bed over mechanical press bed.Defining the Environmental bonds: The structure can be analyzed in half, regarding the symmetry. However for more accurate results, the structure is considered as a whole and the modeling is done.Interpretation of the results: The images above show the assembly of the press bed structure, boundary conditions defined and the results. Static structural and dynamic analysis were carried out and the results were found to be safe. The deflection of the structure was found to be around 0.6 mm. Design modifications were suggested to improve the natural frequency of the structure which resulted in higher stiffness of the structure. Design modifications were performed and the stiffness of the structure increased by 15%.

PRODUCT DEVELOPMENT INTERN SUMMER 2012

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Press Assembly Assembly with boundary conditions

Figure showing Meshing on the structure. Mesh size of 0.01 mm has been used.

Analysis results

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This project aimed at optimization of the fillet radius located inside the filter bowl using parametric study, response surface and design of experiments to minimize the maximum stress induced in the filter bowl. Subsequently, qualification of the complete assembly was performed as per the customer requirements by carrying out pressure analysis for normal operating, proof and burst pressure cases, acceleration and random vibrations analysis is X, Y, Z directions to obtain Margins of Safety (MS) and Fatigue Damage Ratio (FDR). The completed analysis was performed using ANSYS 16.0 and Design Modeler (CAD Module of ANSYS)

Model Preparation:

The model is first set up wherein an optimized fillet of 0.475 in is considered for the qualification studies. The fittings are replaced with filled solid with negligible density thereby, simplifying the simulation of the model. Point masses are applied at the CG of these fittings to compensate for their masses. This is a very common technique adopted in the industry to minimize the complexity of the geometry and the application of the point mass is an effective method of balancing the pressure loads that are being acted on the filter assembly. The tension in the bolts that fix the bolts to the flight body is compensated by applying a fixed support boundary condition to the imprinted circular regions on the under-surface of the valve manifold which is determined by the base of a frustum that holds the bolts. The fluid that applies the pressure on the inner surfaces of the assembly are not modeled, but the mass of the fluid is accounted for by adding 2/3rd of fluid mass to the mass of the filler bowl and 1/3rd to the valve manifold respectively. Additional, model modifications like defining the appropriate contact surfaces are made before the model is tested for the different analysis cases.

Convergence Study:

A convergence study is successfully carried out on the assembly to justify that the location of the maximum stress by locally refining the faces of the valve manifold and filter bowl where the maximum stress is obtained when the assembly is meshed at 0.2 inches element size. The following data provides the convergence study wherein the maximum von-mises stress converges at a local mesh size of 0.0125 inches with an error percent of less than 4% as per the specifications. The material is safe as the maximum stress induced in within the yield strength of the material properties. The images on the following page show the areas where the mesh is locally refined.

STRUCTURAL ASSESSMENT AND ANALYSIS OF THRUST VECTOR CONTROL (TVC) HYDRAULIC SYSTEM FLIGHT FILTER MANIFOLD NOVEMBER 2015 – DECEMBER 2015

TVC Filter and Manifold Assembly Model

Model with mesh size of 0.2 in

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Fixed Support at Contact Regions 0.0125 inch Local Mesh on Filter Bowl

Fittings replaced with solid and point mass applied at the CG 0.0125 inch Local Mesh on Valve Manifold

Pressure Surfaces inside the Filter Bowl Pressure Surfaces inside the Valve Manifold

Force Imbalance (Measurement & Rectification):During the static cases, force reaction is checked for by applying a reaction probe at the fixed support of the assembly. Force imbalance is observed in the Y-direction due to the gaps and anomalies in the geometry of the model assembly arising due to the model modification done initially to simplify the simulation of the TVC Hydraulic filter assembly. Reaction probe applied at the fixed supports depicts the force imbalance in the assembly. The total reaction force in along each component of the direction is required to be lesser than 5 lbf. as per the specified requirements. Therefore, this imbalance in the force is balanced by applying 96 psi of additional pressure to the inner top surface of the filter bowl to obtain the net reaction force within the specified requirements. The maximum von-mises stress induced in the system is then recorded for the qualification of the assembly.

Convergence Study

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Test Specifications:Note: All qualifications require material to be characterized at maximum flight environment temperature: 135 ⁰C [275 ⁰F] • Normal Operating Pressure Case: 3200 psi• Proof Pressure Case (1.5 x NOP): 4800 psi• Burst Pressure Case (2.5 x NOP): 8000 psi

• Acceleration Cases: +1g acceleration applied in X, Y, Z directions. (Results to be scaled appropriately when performing Margin of Safety and Fatigue Damage Ratio calculations).

Scaling Factor: 6.22 x Result for X - Direction analysis 2.00 x Result for Y & Z – Direction analysis

• Random Vibration in X, Y, Z direction. Longitudinal: X – Direction Tangential: Y – Direction Radial: Z – Direction

Component MaterialYield

Allowable, ksi

Von Mises Stress, ksi

Von Mises Stress, Mpa MS

Manifold 7050 - T73511 48.38 23.64 163.02 1.05Bowl 7075-T7351 39.36 30.65 211.35 0.28

Component MaterialYield

Allowable, ksi



Manifold 7050 - T73511 48.38 35.41 244.14 3.7E-01Bowl 7075-T7351 39.36 41.27 284.54 -4.6E-02

Component MaterialUltimate

Allowable, ksi



Manifold 7050 - T73511 70.00 52.57 362.44 0.33Bowl 7075-T7351 46.80 41.68 287.37 0.12

Results – Pressure cases

Proof Pressure

Burst Pressure

Normal Operating Pressure

Results –Acceleration cases

Component Material

Allowable Stress (Fty,

ksi)VonMises Stress, ksi

VonMises Stress, Mpa MS

Axial (X) Dir

Manifold 7075 - T652 48.38 0.123 0.851 391.06Bowl 7075-T7351 39.36 0.150 1.033 261.61

X-Direction (+6.22g)

Component Material




Lateral (Y) Dir

Manifold 7075 - T652 48.38 0.01 0.094 3544.47Bowl 7075-T7351 39.36 0.01 0.066 4121.07

Y-Direction (+2.00g)

Component Material




Lateral (Z) Dir

Manifold 7075 - T652 48.38 0.05 0.318 1047.05Bowl 7075-T7351 39.36 0.05 0.328 827.04

Z-Direction (+2.00g)

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Maximum Von-Mises Stress – Normal Operating Pressure

Maximum Von-Mises Stress – Proof Pressure

Maximum Von-Mises Stress – Burst Pressure

Maximum Von-Mises Stress – Axial (X) Acceleration

Maximum Von-Mises Stress – Lateral (Y) Acceleration

Maximum Von-Mises Stress – Lateral (Z) Acceleration

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Direction Component MaterialSigma (s)

LevelVonMises Stress (ksi)

VonMises Stress (Mpa)

Expected Cycles, N

Required Cycles, n FDR S FDR

Radial (Z) Dir

Manifold 7075 - T652

1s Level (68.3%) 3.519 24.260 1.00E+08 2.59E+06 0.026

0.0382s Level (27.1%) 5.278 36.390 1.00E+08 1.03E+06 0.0103s Level (4.33%) 10.556 72.781 1.00E+08 1.64E+05 0.002

Bowl 7075-T7351

1s Level (68.3%) 1.910 13.170 1.00E+08 5.39E+05 0.005


Results: Random Vibrations

Radial (Z-Direction) 3σ Stress in Z-Direction




Expected Cycles, N


Longitudinal (X) Dir


1s Level (68.3%) 0.264 1.821 1.00E+08 2.68E+06 0.027


Bowl, F4 7075-T7351

1s Level (68.3%) 0.323 2.229 1.00E+08 5.41E+05 0.005


3σ Stress in X-DirectionLongitudinal (X-Direction)




Expected Cycles, N


Tangential (Y) Dir


1s Level (68.3%) 0.021 0.141 1.00E+08 4.12E+07 0.412


Bowl, F4 7075-T7351

1s Level (68.3%) 0.016 0.110 1.00E+08 1.85E+07 0.185


3σ Stress in Y-DirectionTangential (Y-Direction)

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Clockwise from Top-Left Corner: Mode Shapes 1-6 for Random Vibration Analysis

Part Load Case Condition M.S. FDR

Manifold Max Working pressure 275F

1.49E+00 NA

Bowl 2.84E-01 NAManifold

Proof pressure 275F3.66E-01 NA

Bowl-4.62E-

02 NAManifold Burst pressure 275F 3.32E-01 NA

Bowl 1.23E-01 NA

Manifold Acceleration 6.22g Axial (X) Dir

3.91E+02 NA

Bowl2.62E+0

2 NA

Manifold Acceleration 2g Lateral (Y) Dir

3.54E+03 NA

Bowl4.12E+0

3 NA

Manifold Acceleration 2g Lateral (Z) Dir

1.05E+03 NA

Bowl8.27E+0

2 NAManifold Random

VibrationRadial (Z)

DirNA 3.78E-02

Bowl NA 7.86E-03Manifold Random

VibrationLongitudinal

(X) DirNA 3.91E-02

Bowl NA 7.90E-03Manifold Random

VibrationTangential

(Y) DirNA 6.02E-01

Bowl NA 2.71E-01

Margin of Safety & Fatigue Damage Ratio Calculations

Conclusion:The TVC Filter Manifold assembly achieved all the required Margins of Safety as positive values and all the Fatigue Damage Ratios values were lesser than the design limit of 1. MS > 0; FDR < 1 (Requirements)In a nutshell, the TVC Hydraulic Filter qualified by meeting the Margin of Safety and Fatigue Damage Ratio requirements for all the ten analyses with the scope of more accurate results with further detailed analyses.

Response Surface Plots for fillet Optimization

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Overview: The objective of this project was to design and develop two minimum weight skin-stiffener designs of a critical section of an aircraft fuselage one using a metallic material and the other using a composite material.

Design Parameters: • The inner diameter of the critical

section to be designed is 40 in. • The spacing between frames is 20

in. • The design loads were given as

10,000 lb. shear, 200,000 in-lb. torque, and 500,000 in-lb. bending moment as shown in Figure.

Design Constraints:• The skin was assumed to be

only effective in carrying shear loads

• The minimum skin thickness was restricted at 0.032 in.

• The stiffener design was limited only to Z stiffeners with equal top and bottom flange lengths

• Needham’s method was to be employed for stiffener crippling analysis

Methodology:The materials chosen to conduct trade studies for the metallic design were Al 6061, Al 7075-T6, Al 2024-T4, Al-Li 2199-T8E79 and for the composite design, Graphite Epoxy with a 100% ±45° ply orientation was the material selected. The crippling analysis was carried out using Needham’s method. The Factor of Safety (F.S.) was determined for the stiffener using the calculated buckling stresses and for the skin using the calculated shear stresses. MS Excel, MATLAB and Model-Center were employed to conduct the analyses and all of the trade studies for the stiffener design, stiffener spacing, and skin thickness to identify the minimum weight design configurations for both the metallic and composite materials. CATIA V5 was used to design the CAD Model. Trade studies were conducted by varying the number of stringers, skin thickness and dimensions of the stringer. The effect of these changes on the weight of the fuselage and the Factor of Safety of both the stiffener and skin were analyzed using Model-Center. Given the design parameters and design constraints, the F.S. calculated for the skin and stiffeners and was required to be greater than 1 for a suitable design. Numerous configurations were tested before zeroing in on the best designs. The selected material for metallic design was Al-Li 2199-T8E79 which weighed 13.546 lbs. and the Graphite Epoxy composite design weighed 8.821 lbs. The optimized results from the trade studies throughout this project are shown in the following table.

DESIGN OF AIRCRAFT FUSELAGE APRIL 2015- MAY 2015

Attribute Unit MetallicComposit

eNo of Stiffeners in 36 40Skin Thickness in 0.0375 0.0385Stiffener width in 0.5 0.5Stiffener height in 0.5 0.5Stiffener thickness in 0.04 0.04Stiffener Area in2 0.08 0.08

MaterialAl 8090-T8151

Graphite/Epoxy

Fuselage weight lb 13.9396 9.292Factor Safety (buckling) 1.80 3.77Factor of Safety (Shear) 1.016 1.018

Loading Parameters

Final Optimized Results

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My role: Fostered support in the form of Designing and Analysis of metallic and composite fuselage in a group of four people.

FEA Analysis:Fuselage geometry is analyzed by using ABAQUS. Modeling is done in CATIA from which ‘.stp’ file is imported into ABAQUS.Finite Element analysis consists for following important stepsPreprocessing: Element formulationAssemblySolving the equationsPost processing:Determining quantities of interest such as stresses and strains and obtaining visualization of the response.MeshingMaterial and section assignment comes under preprocessing. Boundary conditions are applied to the both ends. One end of the fuselage is fixed by restricting all six degrees of freedom. Bending, Shear and torsional moments are applied to the other end of the fuselage.Meshing is completed in student edition of Abaqus. Following fig shows fuselage mesh with 672 elements. As student version supports only 1000 nodes for analysis, analysis is done with the coarse mesh. Job is then submitted and stresses are analyzed in the visualization window.Results of FEA analysis:Following figure shows the deformed structure of the fuselage with stresses induced in the structure. As mesh is coarse, obtained stresses are slightly varying with the actual one. For analysis 24 number of stiffeners are considered. It can be clearly seen that structure is slightly twisted because of torsional moment.

Conclusion

We have discussed the results for fuselage design using Aluminum alloys and composite material made of Graphite / Epoxy. Both these optimum designs were derived simultaneously by their design approach and optimum weighted fuselage configuration found out by our applied trade study.

Von-Mises stresses in the metallic fuselage with 24 No. of stiffeners

Displacement in the metallic fuselage with 24 No. of stiffeners

Dimensional drawing for Z-stiffener and skin of composite fuselage

Front view of composite fuselage with 40 No. stiffeners

Meshing on metallic fuselage

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Developed an interactive and intuitive GUI that user can easily choose topic of interest, input/modify parameters needed and view the animated/plotted results. The robotics toolbox created can perform the following tasks:Compute homogeneous transformation matricesDetermine rotation matrices for the given Euler angles and vice versaCompute forward kinematics using DH parameters input by the user or determine DH parameters using number of joints, types of joints, link lengths, etc. and then using the DH parameters generated to compute forward kinematicsGraph the workspace of the manipulatorDetermine inverse kinematics given the end-effector poseDetermine the differential kinematics of the manipulator by finding the Jacobian matrix and the singularity of the manipulator for a given poseDetermine inverse differential kinematics and inverse kinematics using JacobianDetermine manipulator dynamics by plotting joint angle vs time and joint rates vs timeBefore using the GUI, the user has to make sure that the Peter Corke robotics toolbox is installed and executed (startup_rvc.m)

Homogeneous Transformation Matrix User Input: Angles of rotation about Z, Y and X axes respectively in degreesPosition vector of the origin of the new frame with respect to the old frame, (31) Position vector of the origin of the new frame w.r.t the origin of the base frame, (31) vector.Output: Plots of Description of a frame Transform mapping Transform vector

MODELING OF ROBOTS USING MATLAB OCTOBER 2015 – DECEMBER 2015

Euler AnglesUser Input: Either input the Euler angles in degrees to get the rotation matrix or input rotation matrix to get the Euler anglesIn both the cases, choose either ZYZ by entering ‘ZYZ’ or ‘zyz’ or choose RPY by entering ‘RPY’ or ‘rpy’Output:Euler angles in case the rotation matrix is givenRotation matrix if Euler angle is given Forward KinematicsUser Input: To have the computer generate the DH Parameters, input number of joints, types of joints, link lengths, etc. in respective cells in the GUIInput the DH ParametersOutput: Transformation matrices Robot-Plot to animate the robot

WorkspaceUser Input: Number of joints, Types of joints, Maximum and minimum angles of rotation, DH ParametersOutput:3D Plot of the workspace

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Inverse Kinematics User Input: DH Parameters or number of joints, types of joints, link lengths, etc., Homogenous transformation matrix of the end effectorOutput: One set of joint variables (in radians for revolute joints) Differential KinematicsUser Input: All the DH Parameters or number of joints, types of joints, link lengths, etc., Number of DoFsOutput: Jacobian for the given pose of the end effector, Message showing whether the manipulator is at a singular configuration for the given pose Inverse Differential Kinematics using JacobianUser Input: End effector homogeneous transformation matrix, End effector velocities, Number of links, Jacobian matrixOutput: Joint velocities, Differential motion Manipulator DynamicsUser Input: Lengths of links, masses of links, masses of motors, moments of inertias of the links, moments of inertias of the motors, gear ratios, distances to center of mass of the links, DH Parameters or number of joints, types of joints, link lengths, etc.Output: Joint angle vs time and joint rates vs time plots.

The master GUI created has the above mentioned 8 options out of which the user can select one. After the selection of an option, the GUI related to the selected task pops up. The various pop-up GUIs and the user inputs required in each GUI are as follows:

Window showing GUI

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Transformation Matrix Description of the frame

Finding forward Kinematics

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Manipulator dynamics

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Concurrent Analysis Private Limited

This project was a part of the degree requirement during my undergraduate at Jawaharlal Nehru Technological University. This project was carried out at Concurrent Analysis Private Limited, Hyderabad. Worked on the project titled ‘Study of thermal storage from the exhaust of a diesel engine’. The exhaust gas from a diesel engine has a temperature of about 600 degree Centigrade. Methods to utilize the heat from the exhaust are already in place. Turbochargers, Intercoolers and Exhaust Gas Recirculators find a wide use in modern diesel powered vehicles. The performance of such auxiliaries can be improved with the help of Computational Methods. The industry, so far, has been reluctant to use such methods and preferred to continue with the empirical and experimental data available. In this paper, the importance of incorporating CFD and other computational methods in designing the equipment has been highlighted. Case studies, to show the contribution of turbochargers and intercoolers in improving the performance of the engines have been presented.

Methods to utilize the waste heat:

1)Turbocharging: A turbocharger, or turbo, is an air compressor used for forced-induction of an internal combustion engine. The purpose of a turbocharger is to increase the mass of air entering the engine to create more power. However, a turbocharger differs in that the compressor is powered by a turbine driven by the engine's own exhaust gases. The major parts of a turbocharger are turbine, wheel, turbine housing, turbo shaft, compressor, compressor housing and bearing housing. A turbo is a small radial fan pump driven by the energy of the exhaust flow of an engine. A turbocharger consists of a turbine and a compressor on a shared axle. The turbine inlet receives exhaust gases from the engine causing the turbine wheel to rotate. This rotation drives the compressor, compressing ambient air and delivering it to the air intake manifold of the engine at higher pressure, resulting in a greater mass of air entering each cylinder. In some instances, compressed air is routed through an intercooler before introduction to the intake manifold. The objective of a turbocharger is the same as a supercharger; to improve upon the size-to-output efficiency of an engine by solving one of its cardinal limitations. A naturally aspirated automobile engine uses only the downward stroke of a piston to create an area of low pressure in order to draw air into the cylinder through the intake valves. In the automotive world, boost refers to the increase in pressure that is generated by the turbocharger intake manifold that exceeds normal atmospheric pressure.

STUDY OF THERMAL STORAGE FROM THE EXHAUST OF A DIESEL ENGINE MAY 2012 – JULY 2012

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Turbocharger parts are costly to add to naturally aspirated engines. Heavily modifying OEM turbocharger systems also require extensive upgrades that in most cases requires most (if not all) of the original components to be replaced. Turbochargers require numerous additional systems if they are not to damage an engine.

2) Exhaust gas recirculation: The main objective of this method to reduce the amount NOx produced. EGR works by re-circulating a portion of an engine's exhaust gas back to the engine cylinders. Intermixing the incoming air with re-circulated exhaust gas dilutes the mix with inert gas, lowering the adiabatic flame temperature and (in diesel engines) reducing the amount of excess oxygen. EGR in Diesel Engines:- In modern diesel engines, the EGR gas is cooled through a heat exchanger to allow the introduction of a greater mass of re-circulated gas. Unlike SI engines, diesels are not limited by the need for a contiguous flame-front; furthermore, since diesels always operate with excess air, they benefit from EGR rates as high as 50% (at idle, where there is otherwise a very large amount of excess air) in controlling NOx emissions. Adding EGR to a diesel engine reduces the specific ratio of combustion gases int the power stroke. This reduces the amount of power that can be extracted by the piston. EGR tends to reduce the amount of fuel burned in the power stroke. This is evident by the particulate emissions that correspond to EGR.

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CFD SIMULATION OF TURBOCHARGER:

Turbo machinery design consists of drawing velocity diagrams in order to understand the flow patterns and also to compute the stage losses. Losses amount to reduction in the efficiency. Traditional methods of design have succeeded in offering good vane designs but the laborious process of making three dimensional velocity triangles can be avoided by using CFD. Below is the figure showing velocity triangles for compressor and turbine.

A simulation of turbocharger using CFD was carried by Mr. Keshav at CAPL. The geometry of the turbocharger was prepared using GAMBIT, which is a pre-processor of FLUENT. The post-processing was done using ANSYS-FLUENT. The simulation was intended to provide an understanding of flow in turbine blades. The results of this study can also be used to understand the onset of secondary and cascade flows. The secondary flows in a turbine are unsteady flows.

The above figure is a snapshot of the simulation on ANSYS FLUENT package. The meshing was done on GAMBIT. A very important fact that has to be understood at this point in time is that for a better turbo machinery design, a full “map” is required. A map is something that gives the required pressure distribution, velocity potentials, leakages at tips, bleeding, etc.

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Intercooler Improvement: It is an established fact that heat transfer rate is higher in turbulent flow than in laminar flow. Therefore it is desired to have turbulent flow in the intercooler. But the exhaust gases come out of the exhaust manifold at a very high temperature and low pressure. According to Bernoulli’s relation, low pressure means high velocity and in turn greater chance of turbulence. Given the complex nature of exhaust gas in terms of composition, flow characteristics, etc. one can only depend on empirical relations to design the device. But with CFD, exact simulation can be performed and the optimum design parameters can be determined. The latest trend is to couple a chemical reaction modeling software with the CFD package. This will greatly enable the analyst with data related to the chemical composition, and thus physical properties, of the exhaust under various conditions. Since CFD can help the analyst choose between various configurations, it can save considerable amount of space. As shown in the figure below, a heat exchanger has been modeled in Pro/ENGINEER WILDFIRE 4.0 and then a vector plot has been prepared. An important observation here would be the contribution of CFD to the design of baffles in the shell.

Case studies were carried out on Tata Super Ace and Toyota Innova BS IV. The result was a more powerful and more fuel efficient engine. The new turbocharged, intercooled engine gives an output of 109 PS, 7 PS more than the previous one. The mileage is around 12.5 km in city and 14 km on the highway with AC on. The new Innova variant costs just 15000 rupees more than the previous version. With increased fuel efficiency and better performance, it’s a small price to pay.

The above figure shows the chassis of Toyota Innova with a 2KD FTV Turbocharged Intercooled Diesel Engine mounted on it.

Conclusions: In this work, we have revisited turbochargers and intercoolers and shown how computational methods can be used to improve their performance. Case studies have been presented which highlight the importance of coupling such thermodynamic devices. This work is a computational approach to the original work of Mr. Ankush Agarwal, carried out at National Institute of Technology, Rourkela in 2009 under the guidance of Professor S.Murugan. In his thesis he carried out experiments on an Ashok Leyland Comet engine. The details of his work can be found in the link provided in references. Our effort has been to understand the procedure behind design and development of turbochargers and intercoolers with the help of CFD.

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Overview: This is a graduate project carried out in the Heat transfer laboratory at JB Institute of Engineering and Technology under MR. Srinivas Kumar. Flows of laminar-turbulent nature are encountered very often in the fins of motorcycle engines and electronic devices. Though the underlying physics of flow transition are not well known, it is an established fact that convectiveheat transfer rates increase as the fluid becomes more and more turbulent. This is not the case in fins, as the effectiveness of a fin drops in high speed flows. In fact, a fin works best in a natural convection environment. In this project, the heat transfer characteristics of a brass fin have been found out in the transitional flow regime. The variation of its efficiency with Reynolds Number of the flow has been found out. The fact that fin efficiency drops with an increase in flow velocity has been reiterated by this project.

Experimental Setup:The experimental setup consists of a duct in which the pin fin is placed and heated externally, a control terminal with controls for varying the heat input, a digital temperature indicator fitted inside the terminal, a manometer tube clamped to the control terminal and a blower clamped at the other end of the duct. The detailed description of the components is given below.The Duct: The duct is essentially an open type suction wind tunnel. It is rectangular in shape with the length being 150mm and breadth being 100mm. The hydraulic diameter of the duct is 120mm. The duct has a converging mouth to draw in more air. The length of the duct is 75cm. The duct is rested on two steel legs provided with rubber studs to damp vibrations. It also has a hinged door on the top at a distance of 34cm from the entrance to provide natural convection environment to the pin fin. It has a provision for clamping the suction end of a blower at its discharge end.The Blower :The blower used in this setup is a Black and Decker KTX 5000. It has a maximum discharge of 3.5m3/min. It comes with a regulator to vary the speed of the impeller. The suction end has a 1 inch inlet and the discharge end can be fitted into a 40mm pipe. In this setup, the discharge end of the blower is fitted into a 1 metre long pipe which accommodates a 22mm orifice meter and a gate valve at the end to regulate discharge. The orifice meter is connected to a U-Tube manometer by two rubber tubes. The manometer limbs are filled with water to a height of 17cm from the apex. The blower is clamped to the rectangular duct and provided with rubber dampers to damp out vibrations.

EXPERIMENTAL AND ANALYTICAL STUDIES OF HEAT TRANSFER FROM A PIN FIN IN TRANSITIONAL FLOW

REGIMEJANUARY 2013 – MAY 2013

Fins of various shapes and sizes. Source: Ulfbastel

(Wikipedia universal license).

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Control TerminalThe control terminal consists of a built in voltmeter, ammeter, digital temperature indicator and a regulator in increase or decrease voltage and current. All these are enclosed in a stainless steel cabinet and exposed to the operator via slots. The electric power is provided by a 440 volt supply. A hinged door is provided at the back of the terminal to access its components. The door is screwed to the cabinet. The control terminal is shown in figure below.

Digital Temperature IndicatorThe digital temperature indicator has 12 channels. The two wires of the T type thermocouple can be inserted into the slots provided on the back of the indicator. They are screwed to prevent disengagement. There are three rows of eight slots for 12 thermocouples.

Figures showing the Control Terminal

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Pin Fin and Heater: The fin is a brass rod of circular cross section. Its diameter is 12mm and its length is 110mm. Its thermal conductivity is 110W/mK. A 30mm extension of 20mm diameter is provided at the back of the rod for the installation of the band heater. A ceramic band type heater has been used in this project. The band heater has been provided with a rubber insulation to minimize heat loss due to natural convection. An Aluminum cap covers and protects the heater setup. The fin has been provided with five holes, which contain internal threads, to clamp the thermocouples using brass bolts.

Thermocouples: ‘T’ type thermocouples have been used in this project. Type T (Copper-Constantan) thermocouples are suited for measurements in the −200 to 350 °C range. Often used as a differential measurement, only copper wire touches the probes. Since both conductors are non-magnetic, there is no Curie Point and thus no abrupt change in characteristics. Type T thermocouples have a sensitivity of about 43 µV/°C. In this project, the thermocouple probes are rings of 6mm inner diameter and 8mm outer diameter. Two thermocouples were used for measurement of ambient temperature in order to eliminate errors. The thermocouples were clamped onto the fin using brass bolts and nuts. Five thermocouples were arranged from root to tip of the fin at equal intervals of length. The temperature indicator had a knob to select the required channel and view the temperature measured by the corresponding thermocouple. The fin with thermocouples mounted on it is shown in the figure below.

Fin with Thermocouples mounted on it

Relation between limb height difference in manometer and dischargeThe discharge from an orifice meter is given by , Eq. (1) Where Cd is the coefficient of discharge of the orifice meter, ‘h’ is the

difference of the level in the limbs of the manometer, a0 and a1 are the cross

sectional areas of the orifice and the pipe respectively. The diameter of the orifice is 22mm and that of the pipe is 40mm. Hence they are constants. The coefficient of discharge, as mentioned in the equipment’s user manual, is 0.64.Therefore, equation can be written as h=(Q^2 (a_1^2-a_0^2 ))/(〖 2gc〗 _d^2 (a_1 a_0 )^2 ) Eq. (2) In the above equation, all the terms except Q2 are constants. Hence the equation turns out to be h=564.94×Q^2 Eq. (3) This is the relation between the difference in the levels of the manometer limbs and the discharge from the orifice meter or the pipe.

Experimentation: As the objective of the project was to find the efficiency of the fin in transition flow regime, the flow in the duct was maintained at Reynolds numbers between 2000 and 4000. The Reynolds numbers were chosen at an interval of hundred. The blower regulator was maintained at position 2 and the discharge was regulated by the gate valve. The correlation between the height difference of the water column in manometer tube and the Reynolds number is shown below.

Hydraulic Diameter of the DuctThe duct has a rectangular cross section. The length of the rectangular duct is 150mm and its breadth is 100mm.

The hydraulic diameter is given by

Where A is the area of the rectangular duct and P is its perimeter.

A = 150 x 100 = 15000mm2.

P = 2(150+100) = 500mm.

Hydraulic Diameter = 120mm = 0.12m.

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Element of fin showing heat

transfer.

Fin Efficiency and Effectiveness:Fin Efficiency is defined as the ratio of actual heat transferred to the heat which would have been transferred if the entire fin area were at base temperature. It is given by, . Fin Effectiveness is defined as the ratio of heat transferred with fin to that without the fin [9][10]. It gives the measure of the effectiveness of the fin in terms of transferring heat. Low values of effectiveness mean that the fin is unnecessary. Fin effectiveness is given by . The above relations are for a fin with an insulated tip.

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Setting the Reynolds Numbers: The duct in which the fin is placed is rectangular in cross section. For such non circular ducts, dimensionless numbers are calculated using the “hydraulic diameter”. Hydraulic diameter, Dh, is widely accepted as four times the cross sectional area over wetted perimeter. Usually, the transitional flow regime is said to exist between Reynolds numbers 2000 and 4000. The onset of transition is observed at a Reynolds number of 2300. The blower is a steady state device, i.e. mass is neither created nor destroyed in it. Therefore, the continuity relation stands valid. The Reynolds number is given by , Where, ρ stands for mass density of air,V is the velocity of flow in the duct, µ is the dynamic viscosity of the air.The velocity of air in the duct, V is given by V= Q/A, where A is the area of cross section of the duct. Now Reynolds number of the flow in the duct can be rewritten as Eq. (4)A clear relationship thus exists between the Reynolds number in the duct and the discharge. The relationship between Q and h has been made clear by equation Eq. (1)The protocol followed during the experiments was:Obtain the discharge by setting the Reynolds number via Eq. (4)Obtain Q2.Obtain h via Eq. (3)

Reynolds NumberDischarge

Q×10-3(m3/s) Q2×10-5(m6/s2)h= 564.94× Q2 (mm

of water)

2000 4.0746 1.660 9.37

2100 4.278 1.830 10.34

2200 4.482 2.0088 11.34

2300 4.6857 2.1956 12.40

2400 4.8895 2.3907 13.50

2500 5.0935 2.5941 14.65

2600 5.264 2.771 15.65

2700 5.500 3.025 17.09

2800 5.7044 3.254 18.38

2900 5.9081 3.490 19.72

3000 6.149 3.782 21.37

3100 6.3549 4.0385 22.81

3200 6.559 4.303 24.31

3300 6.6812 4.4639 25.21

3400 6.9268 4.798 27.10

3500 7.1305 5.0844 28.72

3600 7.2890 5.3130 30.00

3700 7.5380 5.6821 32.10

3800 7.7417 5.9934 33.85

3900 7.9454 6.3130 35.66

4000 8.1492 6.6409 37.51

Level difference in the manometer limbs against Reynolds numbers

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The impeller of the blower was set at position 2 and the height difference in the manometer limbs was controlled by the gate valve. The ceramic type band heater was switched on for around 45 minutes before each run in order to ensure attainment of a steady state temperature by the fin. The maximum temperature attained by the fin during the experiments was 55 degrees Celsius while the least high temperature was 53. The blower was turned on at position 2 for a period of twenty minutes and the temperatures were taken. The average wall temperatures were computed. The ambient temperature during each run and the average wall temperatures have been tabulated against the Reynolds numbers.

Serial Number Reynolds NumberAmbient Temperature

(0C)Average Wall

Temperature (0C)1 2000 33 47.502 2100 33 45.503 2200 33 46.004 2300 33 45.375 2400 33 46.256 2500 33 45.757 2600 32 45.258 2700 33 44.759 2800 33 45.25

10 2900 33 45.5011 3000 34 45.0012 3100 34 45.7513 3200 34 43.5014 3300 32 45.5015 3400 33 46.0016 3500 33 46.2517 3600 32 42.2518 3700 32 45.519 3800 33 46.520 3900 32 46.0021 4000 33 46.25

In forced convection heat transfer the properties like its mass density, specific heat capacity, Prandtl number, thermal conductivity, etc. are calculated at the “film temperature”. Film temperature is usually taken as the average of the wall temperature and the ambient temperature. The properties of the air at various film temperatures encountered during the experimentation are tabulated below.

Reynolds Number

Film Temperature

(0C)Mass

Density(kg/m3)

Specific Heat Capacity, Cp

(kJ/kg-K)

Thermal Conductivity, k

(W/mK)Prandtl Number

2000 40.25 1.129 1.006 0.02724 0.70502100 39.25 1.133 1.006 0.02716 0.70502200 39.50 1.132 1.006 0.02718 0.70502300 39.18 1.133 1.006 0.02716 0.70532400 39.62 1.132 1.006 0.02719 0.70522500 39.37 1.133 1.006 0.02717 0.70522600 38.62 1.135 1.006 0.02712 0.70542700 38.87 1.134 1.006 0.02714 0.70532800 39.12 1.133 1.006 0.02715 0.70532900 39.25 1.133 1.006 0.02716 0.70533000 39.50 1.132 1.006 0.02718 0.70523100 39.87 1.131 1.006 0.02721 0.70513200 38.75 1.135 1.006 0.02713 0.70543300 38.75 1.135 1.006 0.02713 0.70543400 39.50 1.132 1.006 0.02718 0.70523500 39.62 1.132 1.006 0.02719 0.70523600 37.12 1.141 1.006 0.02700 0.70573700 38.75 1.135 1.006 0.02713 0.70543800 39.75 1.131 1.006 0.02720 0.70513900 39.00 1.134 1.006 0.02714 0.70534000 39.62 1.132 1.006 0.02719 0.7052

Level difference in the manometer limbs against Reynolds numbers

Average wall temperatures tabulated against Reynolds numbers

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The data above enables us to find the convective heat transfer coefficient and subsequently the rate of heat transfer. Nusselt number is to be found to calculate the film coefficient. Nusselt number is defined as the ratio of convective heat transfer coefficient to conductive heat transfer coefficient. According to Hilpert, the relationship between Nusselt number, Reynolds number and Prandtl number for gases is given by Eq. (5)Here Ref stands for the Reynolds number for the flow around the fin. It is given as

Eq. (6) Where, d stands for the diameter of the fin which is 12mm. C and n in equation (5) are taken from Hilpert’s chart as 0.453 and 0.466 respectively for Reynolds numbers between 40 and 4000. The equation 5.8 can be rewritten as Eq. (7)In the above equation, ʋ is the kinematic viscosity. It is the ratio of dynamic viscosity to mass density. From the Nusselt number obtained from equation (5), one can compute the film coefficient, also called as the convective heat transfer coefficient, from the below relation Eq. (8)Where, hf is called the convective heat transfer coefficient,

d is the diameter of the fin,k is the thermal conductivity of the fin material.The Nusselt numbers and film coefficients thus obtained are tabulated against the Reynolds numbers of flow over the fin:

Reynolds Number for flow around the fin, Ref. Nusselt Number

Convective Heat Transfer Coefficient, hf (W/m2K).

194 4.69 10.64

204 4.80 10.86

213 4.90 11.09

223 5.01 11.34

232 5.10 11.56

243 5.21 11.80

251 5.29 11.95

262 5.40 12.20

272 5.50 12.44

281 5.58 12.62

293 5.69 12.88

302 5.77 13.07

313 5.87 13.31

319 5.92 13.38

330 6.01 13.58

340 6.09 13.80

349 6.17 13.88

358 6.24 14.10

369 6.33 14.35

377 6.40 14.48

388 6.49 14.71

Nusselt numbers and Film coefficients against fin Reynolds numbers:

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Fin Efficiency Fin efficiency, as defined earlier, is the ratio of actual heat transferred by the fin to the heat that would have been transferred if the entire fin area were at base temperature. In this case, the fin efficiency would be, Where, Q is the rate of heat transfer tabulated Tb is the base temperature. As mentioned earlier, the maximum temperature attained by the fin after reaching a steady state was 550

Celsius. This temperature was recorded at the base of the fin, i.e. just ahead of the 3cm extension provided for the installation of the band heater. This temperature is the base temperature. The fin efficiencies are tabulated against the Reynolds numbers of flow inside the duct:

Conclusion:

The fin efficiencies show a decreasing trend in the first quarter of the above table, and a steady trend in the last quarter. The efficiencies in the middle of the table follow no particular trend. The fact that a fin performs best under extremely low velocity-forced convection or in natural convection is reiterated. The above data on fin efficiencies has a mean of 58.76 and a standard deviation of 4.65.

Reynolds number of flow in the duct, Red Fin Efficiency (%)

2000 64.31

2100 55.42

2200 57.66

2300 54.88

2400 58.76

2500 56.55

2600 56.21

2700 56.11

2800 54.33

2900 55.44

3000 51.11

3100 54.60

3200 44.14

3300 57.27

3400 57.65

3500 58.76

3600 43.48

3700 57.27

3800 59.87

3900 59.39

4000 58.76

Reynold’s number vs Fin Efficiency

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Simulation of the above experiments was carried out on a mini computer in order to confirm the validity of the results obtained and to know the difference between the actual and analytical results. A model of the pin fin was created in Autodesk Inventor Fusion 2013 and a transient heat transfer analysis was carried out in Autodesk Simulation Multiphysics 2013.A three dimensional model of the fin was created in Autodesk Inventor Fusion 2013. A hole was created exactly in the middle of the portion exposed to convection with the same dimensions as the real fin. The figures show the fin with mesh and boundary conditions applied. Simulation is carried out at different Reynolds number.

Model of the Fin in Simulation Multiphysics

Fin Model with Mesh and boundary conditions

Simulation on the Fin at Reynold’s number 2000

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Fin Efficiencies plotted against Reynolds Numbers:The fact that the efficiency of a fin decreases with an increase in the velocity of fluid flowing around it is reiterated by the experimental results obtained. The fact that a natural convection environment is best suited for obtaining good heat transfer performance is well known. The experimental results prove the same. The graph below shows fin efficiencies plotted against Duct Reynolds Numbers.

A clearly decreasing trend observed between Reynolds Numbers 2000 and 3100. A stable trend is observed afterwards. Fin efficiency, as witnessed in the above graph, has no significant variation in the transitional flow regime.

Experimentally obtained Heat Transfer Rates vs. Duct Reynolds Numbers:

An increasing trend is observed when the experimentally obtained heat transfer rates are plotted against duct Reynolds Numbers. 0.840W/s is the highest recorded value, at Reynolds Number 3900. The least heat transfer rate was recorded at Reynolds Number 3200. Its value was 0.524W/s.

Fin Efficiency VS Reynold’s number

Heat Transfer Rate VS Reynold’s number

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This project was a part of my course MAE 571 Fluid Mechanics at Arizona State University. For a Hele Shaw flow the condition required is Re(h/L)2<<<1Where ‘Re’ is the Reynolds number, ‘h’ is the Height of the pipe, ‘L’ is the Length of the pipe, ‘nu’ is the Kinematic viscosity, Dynamic Viscosity = 0.1 m2/sec, Density = 1 kg/m3, Velocity = 0.1 m/sec, Reynold’s number = (V*D)/nu = (0.1*90*10-3)/0.1 =90*10-3 m <<<1.Geometry: The model of the pipe is designed using Design Modeler in the ANSYS workbench. Dimensions: D1 = 40 mm, D2 = 90 mm, h = 5 mmProblem Description:MeshingSize of the element = 1 mm, Smoothening = High, Inflation = Default setting, Precision = Double precisionPost Processing: No slip boundary condition, Type of flow: Viscous Laminar Flow, Initialize the solution, Solution Method: Least square based, Number of iterations performed: 250. Streamline plots are plotted for various values of h and different values of viscosity.

Conclusion: By Increasing the Viscosity by 45 times we have the flow transition to form Hele Shaw Flow.

Flow over an aero foil: Simulation of flow over an aero foil model was done using Matlab. Contours of velocity potential and stream function are plotted. The simulation results are as follows:

Simulation of Hele-Shaw Flow NOVEMBER 2014 – DECEMBER 2014

Streamlines plots for different values of Height ‘h’

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Overview:The project was a part of my course MAE 598 Design Optimization at Arizona State University. The project focusses on optimizing the wind turbine system which include the blade design and the foundation primarily and subsequently optimizing the selection of wake model and the wind farm layout. For optimizing the blade design the twist angle and blade length were found to have a significant impact on performance. Maximum Cp achieved is 0.456 which is 77% of the Betz

limit. For the second sub-system the basic objective of the study is to find out the most optimal wake model for the optimization of wind farm layout depending on capacity factor of the two models being analyzed in this project. The hub height of the turbine is taken as 100 mts. Capacity factor versus land area per turbine with varying wind velocity are plotted. The results are analyzed and the best wake model is selected based on the highest capacity factor obtained. The main task of a wind farm is to get as much energy as possible from the minimal number of wind turbines and with a minimal space between the turbines due to the economy of land and connections costs in offshore. For the offshore wind farms, the wake effect is especially significant. The planning tasks for wind farms with an incorporation of the wake model in order to maximize the energy yield, such as optimal farm configuration, has been discussed. For the fourth subsystem the objective is to minimize the cost involved in the construction of the foundation. The prime constraints that were analyzed includes soil pressure constraint, foundation stiffness constraint, overturning constraint and bearing capacity constraint.

Following the formulation of the constraints the optimization was performed using Matlab fmincon algorithm and satisfactory results were obtained for thickness and diameter as 0.5 m and 12.214 m respectively. I was working on the optimization study of the blade parameters.DESIGN PROBLEM STATEMENTOptimization of the wind turbine blade parameters:Maximize Cp, the expected performance co-efficient (power co-efficient)

while maintaining sufficient blade thickness to avoid structural stress violations. Cp = Extracted Power . 0 < Cp < Betz limit (ideal)

Available Power in Wind The outputs determined from engineering analysis are, the amount of torque generated, and the resulting thrust force. Design parameters include blade length, twist angle, tip speed, thickness of the blades and the upstream wind speed. Optimum combination of these parameters maximize the efficiency.

Wind Stream Direction

Where F1 causes torque and F2 defines the aero foil design for integrity.

OPTIMIZATION OF WIND TURBINE SYSTEM JANUARY 2015- MAY 2015

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Objective:Maximize: Cp- Performance co-efficient Betz limit Cp= 0.593 (ideal) Cp = T x ῳ = Shaft Power 0 < Cp < Betz limit Eq. (1)

. ½ x ṁ x Vw 2 K.E of Wind

ṁ = ƥ x A x Vw (kg/s) Eq.(2)

A = ᴨ x R2 (m2) Eq. (3)ῳ = Vt / R (rad/s) Eq. (4)

T = T (β, R, Vw) Nm Eq. (5)

Eq. (6)

Since there is no explicit relation between Torque and blade parameters like twist angle and length also upstream wind velocity. Simulations were performed for a set of samples for a range of afore mentioned parameters to gather data. The sample space with 40 sets of parameter combinations was generated using LATIN HYPERCUBE Sampling method. Tools used for simulation and meta-modelling in MATLAB N-N toolbox are: 1) Autodesk Inventor2) Hyper mesh 3) ANSYS-CFX/Fluent4) ANSYS FSI5) Neural Network (MATLAB)

Minimize (1/Cp) = ƥ x ᴨ x R3 x Vw 2 2 x T(β, R, Vw) x Vt

CONSTRAINTS:

Due to noise control regulations followed globally for onshore turbinesVt < 82 m/s Eq. (7)For infinite life design based on S-N curve for Aluminium σcf + σb < 120 MPa Eq.(8)

[(Pr + Pt) / 2] x ƥAl x Vt2/ Pr + M (β, R, Vw) x Y < 120 x 106 Pa Eq.(9)

σcf = [( mb x Vt2 ) / R ] / Root CS Area Eq. (10)

mb = [(Pr + Pt) / 2] x t x R x ƥAl Eq. (11)Root CS Area =Pr x t = 2.034 x t ( m2) Eq. (12) Pr =2.084 m and Pt=1.927 m from CAD software Eq. (13)σb = M (β, R, Vw) x Y Eq. (14)I = (7.58*t^2)+(0.502*t)+0.0008 m4 (MATLAB Curve fit) Eq. (15)Y = Distance from blade centroid to outermost point of root

Since there is no explicit relation between M and blade parameters like twist angle and length also upstream wind velocity results were obtained from simulations (Appendix 2.1.6) and meta-modelling is done.

M= f (β, R, Vw) => Simulation Results=> M= net (β, R, Vw )

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MODEL ANALYSISRoot aerofoil - S814 Tip aerofoil - S813These two aerofoils are chosen for this project because of their good Cl / Cd ratio for Re number encountered in operation (nrelairfoiltools.com).The bounds for the parameter are made considering the logistic limitation (standard trailer truck 17.4 m long), general engineering principles and limitations followed by wind turbine manufactures in world.10 < R < 16 m0 < β < 45 degrees3.5 < Vw < 25 m/s ( Cut-in speed and Cut-out speed)

4 < t < 25 mm (Standard thickness of Aluminium plate extrusions)Decreasing the amount of taper increases power captured from the wind but at the cost of an increased thrust force. So for simplicity un-tapered blade design is chosen i.e.) lambda = Tip chord length = 1 Root chord lengthAssumptions:1) Blade is considered to be made of Aluminum and it is assumed that the entire mass is concentrated at the tip of the blade which gives worst case scenario for centrifugal force.2) Two metal webs of constant thickness 12 mm each runs for the entire length of the blade shell which helps in resisting centrifugal and thrust forces. Thickness variation of the blade shell is considered only under constraint function for structural limitations.3) The mechanical loss and generator loss are ignored in this study.

OPTIMIZATION STUDYFor optimization work fmincon function of MATLAB was used. The objective and constraints are set along with the bounds on the blade parameters. The turbine manufacturers in market typically rate their products at upstream wind velocity of 8 or 10 or 12 m/s. So the optimizer is run by fixing the parameter Vw at 8, 10 and 12 m/s. The results are tabulated.

It can be seen that the constraint on tip velocity is always active constraint. This result is concurrent with onshore products in market. With different Vw parameter values the

optimum changes as expected since at higher wind speeds stalling and drag dominates in flow over blade.Parameter Study:Wind Speed Vw:

At higher wind speeds (Vw) stalling and drag dominates flow over the blade so the efficiency

decreases. The power output increases with wind speed because the wind contains more Kinetic Energy. Turbine’s ability to extract K.E of wind decreases with increase in wind speed.RESULT DISCUSSIONIn real world tapered blade are always used and material used in blade manufacture is glass fiber epoxy which is a strong and light weight material. This leads to thinner and lighter blades. The accuracy of the meta-model for T = net1 (β, R, Vw) and M = net2 (β, R, Vw)

influences the results. For the optimum output values of these parameters (β*, R*, V w*)

simulation is run and response for T is obtained and compared with prediction from meta-model T= net1 (β*, R*, Vw*) .The comparison showed a initial variation of about 8%.

Mini. Maxi.Wind Vel. β (⁰) R (m) t(mm) Vt (m/s) 1/Cp Cp

8 27.35 10.92 12.82 82 2.1925 0.456110 29.80 14.99 14.91 82 4.5338 0.220612 38.80 11.19 13.06 82 6.4554 0.1549

Maxi. Value

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Volunteering for Sun Devil Racing – Formula SAE at Arizona State University, Tempe. Working on the Design and Analysis of the brake rotor. Designed the model using Solidworks and Analysis is carried out using Ansys 16.0. Formula SAE is a student design competition organized by SAE International (SAE, previously known as the Society of Automotive Engineers). My other responsibilities include: Fabricated various components of the FSAE car like side covers, chassis, and drive-train components. Troubleshooting issues like the performance and errors in manufactured components.

The figures show the static structural and the thermal analysis of the brake rotor.

VEHICLE ENGINEER OCTOBER 2015 – PRESENT

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