EXPERIMENTAL AND COMPUTATIONAL ANALYSIS OF HEAT TRANSFER IN A SHELL AND TUBE HEAT EXCHANGER

Samiullah Qureshi

Dr.Abdul Fatah Abbasi

Qadir Nawaz Shafique

Sanjay Kumar Menghwar

Teaching Assistant/M.E Student

Mech: Engg: Dept.MUET Jamshoro

ProfessorMech: Engg: Dept.

MUET Jamshoro

LecturerMech: Engg: Dept.:

MUET SZAB Campus KHP Mir’s

Lab Engineer/M.E Student

Mech: Engg: Dept.MUET SZAB

Campus KHP Mir’s

OUTLINE Introduction Literature review Experimental setup Simulation and modelling procedure Results Conclusion References

INTRODUCTION To exchange heat between two fluids → heat exchanger

Different types → Air conditioning , Power production,

Space heating

Widely used type → shell and tube heat exchanger

Consist of bundle of tubes enclosed in cylindrical shell

Efficient & energy saving heat exchanger →

Researchers conducts experimental and numerical

work

INTRODUCTION In this study,

Experimental and CFD Investigation of Parallel and

Counter Flow in STHEx

CFD Software → ANSYS Fluent

Simulated result Heat Transfer coefficient ,

Effectiveness

Compared with Experimental data

Also effect of mass flow rate → performance of heat

exchanger

M. Thirumarimurugan et al. [1] developed numerical model in MATLAB

Predict outlets temperature Simulated results compared

.Žarko Stevanović et al. [2] → 3-D numerical study Fluid flow and heat transfer Chen-Kim modification of k − ε model → good agreement with

experimental data Optimal flow distribution → reduce pressure drop , enhance heat

transfer Ender Ozden, and Ilker Tari [3] conducted → CFD study

Design of STHEx → baffle spacing, baffle cut Simulated results compared → kern and Bell-Delaware methods

LITERATURE REVIEW

EXPERIMENTAL SETUP Arm field HT33-XC-304 SHTHx → Heat transfer lab , MUET Stainless steel tubes , acrylic transverse baffles and shell Water heated in the vessel → electrical heater Hot fluid passes through S.S tubes → pump Tap water → Cold fluid Experiment performed for Counter and parallel flow

Hot fluid → 0.076 kg/sec , Tin = 60°C

Cold fluid → 0.036 kg/sec , Tin = 24°C

Heat Exchanger Specification (provided by Armfield limited)

S.No Description Unit Value1 Shell inner diameter mm 39

2 Shell wall thickness mm 33 Tube outer diameter mm 6.35

4 Tube wall thickness mm 0.6

5 Number of Tubes mm 76 Shell/Tubes length mm 150

7 Shell inlet/outlet length mm 10

8 Baffle height mm 34.59 Baffle Thickness mm 3

EXPERIMENTAL SETUP

SIMULATION AND MODELLING PROCEDURE

Geometry Geometry in ANSYS design modeler Simplified geometry – 2D

Actual Model

Simplified Model

SIMULATION AND MODELLING PROCEDURE Meshing

Carried out in ANSYS Meshing Client

Whole fluid domain → Quadrilateral element type

Initially Coarser meshing → 18330 elements

Better Result → Fine meshing - 73370 elements

SIMULATION AND MODELLING PROCEDURE Models and Governing Equation

According to system specification , some models need to be adopted in CFD Software

In ANSYS Fluent → two built in HEx models Heat Exchanger Model:

DUEL CELL heat exchanger model Based on NTU method

Flow is turbulent → Turbulent model Should be selected

SIMULATION AND MODELLING PROCEDURE Governing Equation

k-ɛ Turbulence Model Turbulent kinetic energy k

Turbulent dissipation ɛ

Turbulent viscosity vT

SIMULATION AND MODELLING PROCEDURE Governing Equation

Conservation of Mass:

Momentum :

Energy:

BC Type Shell TubeIntel Mass-flow 0.034 Kg/sec 0.076 Kg/sec

Outlet Pressure outlet 0 0

Wall No slip condition Zero heat flux Zero heat flux

Turbulence Turbulence intensityLength scale

5.62%0.007 m

4.24%0.00036m

Temperature Inlet temperature 297 K 333K

SIMULATION AND MODELLING PROCEDURE Boundary Conditions

Selected according to need of model

T

RESULT Parallel Flow

Temperature contours

→ Shell Side

INLET

OUTLET

→ Tube side

INLET

OUTLET

Experimental Simulated Diff:

Tube side Temp: difference 2.8 2.6 7.14%

Shell side Temp: difference 6.2 5.7 8.06%

Overall HT co-eff: (W/m2.K) 1432 1310 8.55%

NTU 0.201 0.184 8.4%

Effectiveness 0.174 0.162 6.8%

RESULT Comparison of simulated and experimental data

Effect of mass flow rate on Heat Transfer Variation in hot mass flow rate At = 0.038 Kg/sec , U = 1091 W/m2.K , Effect: = 0.1335

With increasing mass flow rate – effectiveness increased

RESULT

100% 200% 300%0%

5%

10%

15%

20%

25%

30%

20.00%21.60%

23.15%21.00%

25.80%27.34%

U (W/m2.K) EffectivenessMass Flow Increment

Incr

emen

t

RESULT Counter Flow

Temperature contours

→ Tube side

INLET

OUTLET

→ Shell side

INLET

OUTLET

RESULT Comparison of simulated and experimental data

Variables Experimental Simulated Diff:

Tube side Temp: Difference 3.4 3.15 7.35%

Shell side Temp: difference 7.5 6.92 7.7%

Overall HT coeff: (W/m2.K) 1765 1623 8.05%

NTU 0.248 0.228 8.06%

Effectiveness 0.208 0.196 5.76%

Effect of mass flow rate on Heat Transfer Variation in hot mass flow rate At = 0.038 Kg/sec , U = 1184 W/m2.K , Effect: = 0.143

With increasing mass flow rate – effectiveness increased

RESULT

100% 200% 300%0%5%

10%15%20%25%30%35%40%45%50%

37.00%42.00% 43.00%

37.00%

44.00% 46.00%

U (W/m2.K) EffectivenessMass Flow Increment

Incr

emen

t

CONCLUSION Effect of Mass Flow rate

Effectiveness is increased with increase in hot fluid flow

Increment of effectiveness in counter flow is almost 90%

more than of that in parallel flow for same mass flow

increment

Effect of Flow Configuration Effectiveness in counter flow is almost 20% to 25% more

than of that in Parallel Flow for same mass flow CFD Analysis

Good agreement with experimental data and theoretical concepts

[1] M. Thirumarimurugan, T.Kannadasan and E.Ramasamy, Performance Analysis of Shell and Tube Heat Exchanger Using Miscible System, American Journal of Applied Sciences 5 (5): 548-552, 2008 [2] Žarko Stevanović , Gradimir Ilić, Nenad Radojković,

Mića Vukić, Velimir Stefanović, Goran Vučković, Design of shell-and-tube heat exchangers by using CFD technique – part one: thermo-hydraulic

calculation, FACTA UNIVERSITATIS Series: Mechanical Engineering Vol.1, No 8, 2001, pp. 1091 – 1105[3] Ender Ozden, Ilker Tari, Shell Side CFD Analysis of a

Small Shell And Tube Heat Exchanger, Energy Conversion and Management, 2010: 51;1004-1014

REFERENCE

THANK YOU