CONDUCTIVE HEAT TRANSFER

APPARATUS P13624

John Durfee, Ryan Murphy, Fielding Confer Dan Unger, Katie Higgins, Robin Basalla

Group Members

Agenda • General Review 3:00pm• Concept Generation Review3:05• Collaboration of Ideas3:10• Refining the Concept3:20• Finalizing the Design3:30• Bill of Materials3:45• Final Drawing3:55• Calculations4:05• Risk Assessment4:15• Testing Procedures4:25• Production Timeline4:30

Questions?

General Review

PurposeTo design a heat conduction apparatus that can illustrate fundamental concepts of heat transfer to students new to hands-on engineering

KeywordsTo quickly outline the primary goals, follow SAMPLE

Safety- minimal risk of student injury Accuracy- correct measurements of

conductivity Mobility- can be maneuvered in and out of

lab Precision- measurements are easily

repeated Longevity- robust materials and long life

span Ease of use- simple assembly,

disassembly, & cleaning

Top Level Function

Uninformed Student

Partial Assembly

Energy

Unknown k

Informed StudentHands-on

ExperienceThermal Energy

Known k

Demonstrate Principle of

Thermal Conductivity

Functional DecompositionDemonstrateThermalConductivity

Creates1-DimensionalHeat Transfer

Minimal heat loss from boundariesGenerates heat fluxProvides proper temperature variationAccepts multiple geometriesAccepts multiple materials/phasesMinimizes resistance at heat exchanges

GeneratesMeasurableData

AccuratePreciseManual collectionDigital collection (Labview)Displays rate of heat fluxDisplays temperature distribution

EnhanceStudent Lab Skills

Requires manual assembly and disassemblyCan be used within given time periodsFits on the chemical engineering cartsHas replaceable components Low maintenanceDurable

Specifications

Specifications

Concept Generation Review

Fundamental Concept

Hot ColdHeat

Conduction

Energy In Energy Out

A temperature gradient will be produced between a Hot and Cold regions

This gradient will be set across a span of Heat Conduction The flow of energy will be allowed to reach steady state The Energy In will be equivalent to the Energy Out The temperature gradient will be measured with a transmission system

Temperature Transmission

Refined Subsystems

Subsystems

Hot

Cold

Specimen

Temp Trans.

Insulation

Liquid flow jacket

Liquid flow jacket

Rectangular prism (bar)

ThermocouplesForm-

fitted Solid

Steam flow jacket

Cold air gun (vortex tube)

Cylinder (rod)

Resistance Thermometer

Form-fitting malleable

Steam flow jacket

Liquid N2

Thermistors

Wrapped

Electric heater

Thermoelectric Device

Coloring Material

Packed

Previous Design Model•Electric cartridge heater placed in a drilled out hole on one end of the specimenHot•Controlled water temperature connected to the other specimen end with a flow jacket fittingCold•Cylindrical rodSpecimen•Probe ThermocouplesTemperature

Transmission•Fiberglass insulation contained within a round plastic casingInsulation•HorizontalOrientation

Concept Comparison

Subsystems

HotCold

Specimen

Temp. Trans.

Insulation

Orientation

Assembly

Previous Design

DATUM

Box- Blocks

000+

0/+0+

Box Clamp

00+++++

Hinged

000++++

Vertical Hinged

Pipe

00

0/++++0

N2 Bath

0-0+++0/-

Box-Blocks Concept•Open for considerationHot•Open for considerationCold•Oriented more towards a rectangular prismSpecimen•A separate thermocouple housing that can be slid in and out of the device on top the specimen

Temperature Transmission

•Solid blocked insulation that can be build around the specimen and fitted togetherInsulation•HorizontalOrientation

Box-Blocks Concept

Box Clamp Concept•Open for considerationHot•Open for considerationCold•Can be fitted for either a bar or a rodSpecimen•Thermocouples travel through a lid region and connect to the specimen

Temperature Transmission

•Solid formed or solid malleable insulation that holds the specimen on the bottom and is covered by an insulated lidInsulation•HorizontalOrientation

Box Clamp Concept

Hinged Concept•Open for considerationHot•Open for considerationCold•Orientated more towards a rodSpecimen•Thermocouples lay in small troughs on one half of the insulation housing and are covered upon closing the device

Temperature Transmission

•Solid formed insulation that holds the specimen between two hinged piecesInsulation•HorizontalOrientation

Hinged Concept

Collaboration of Ideas

Benefits of Each System Box-blocks

Modular pieces that are easily constructed Box Clamp

Simple, rugged assembly Broad range of Insulation can be used Open for any type of specimen

Hinged Minimal disturbance to transmitters

Putting It Together Begin with a sturdy

platform Seat a solid block of bulk

insulation Include a second block

formed to the specimen Cover it with a malleable

slab of insulation Close everything with a

second connected platform

Exploded View Begin with a sturdy

platform Seat a solid block of bulk

insulation Include a second block

formed to the specimen Cover it with a malleable

slab of insulation Close everything with a

second connected platform

Moving Forward Considering previous

decisions, i.e. The Hot Side will use

a cartridge heater The Cold Side will use

a liquid refrigeration unit

The Temperature Transmission will use thermocouples

Moving Forward New subsystems

needed to be identified Heating Connection Cooling Connection Transmitter

Connection

Moving Forward The cartridge heater

can be placed inside the specimen

The refrigerated fluid can cool the specimen with an external jacket

The thermocouples can be tacked to the specimen

Summarizing Previous subsystems

can be used to help categorize new elements

A new list of subsystems has to be generated

Categorized Subsystems Hot Side

Heat Source Heating Connection

Cold Side Cold Source Cooling Connection

Housing Top Bottom Connection

Transmission Transmitter Type Transmitter

Connection Insulation

Upper Middle Lower Sections

Specimen Geometry

Refining the Concept

Current Benefits Modular design Simple assembly Rugged, easily

replaceable components

Minimal stress on transmitter connections

Well insulated energy exchange

Current Issues Need an appropriate

method to tack thermocouples

No feasible material was found for the upper insulation (soft forming)

Unshielded insulation can be damaged

Housing connections need to be addressed

Thermocouple Connections Options

High Temp Solder Adhesive Patches Thermal Epoxy Drilled Holes

Thermocouple Connections Pros

Solder Accurate Solid Connection

Adhesive Patches Simple Modular

Thermal Epoxy Accurate

Drilled Holes Accuracy Modular

Cons Solder

Dangerous Messy

Adhesive Patches Inaccurate

Thermal Epoxy Time Intensive Trades cost for accuracy Messy

Drilled Holes Permanent Added Processing

Upper Insulation Options

Rigid Formed (like middle)

Soft Fiberglass or alternative

Combined Structure

Upper Insulation Pros

Rigid Simple Durable

Fiberglass Cheap Modular

Combination Works best with

ideas Partially modular

Cons Rigid

Needs processing Less modular

Fiberglass Less durable Messy

Combination More complicated Needs processing

Housing Insulation can be

contained within a boxed housing

Did not require much decision making

Slots can be made for the thermocouple wires (as opposed to a long section)

Openings will also be needed on both the Hot and Cold Ends

Housing Connection Options

Hand screws Buckles Structural Offset

Housing Connection Pros

Hand Screws Rugged Solid Closure

Buckles Simple Use Solid Closure

Structural Offset Simple No Processing

Needed Less Expensive

Cons Hand Screws

Needs processing Can be over worked

Buckles Needs processing Less durable

Structural Offset Less Solid Closure

Selections Thermocouple Connections

Drilled Holes Upper Insulation

Rigid and Formed Housing

Box Enclosure Housing Connection

Structural Offset

Finalizing the Design

Still Need to Include Hot Side

Energy Measurement (power source) Cold Side

Coolant Carrier (tubing) Cooling Fluid

Temperature Transmission Data Collection Hardware Data Collection Software

Housing Construction (screws)

Used Specimen Container

Used Specimen Container Holds each

specimen after they have been heated and measured

Isolates heated material from students

Can be moved away from testing area

Uses the same material as the housing device

Final List of Subsystems Hot Side

Energy Management Heat Source Heating Connection

Cold Side Cold Source Cooling Connection Coolant Tubing

Transmission Transmitters Connection Data Collection Hardware Data Collection Software

Specimen Geometry

Insulation Upper Middle Lower

Housing Material Connection Fasteners

Used Container Material Insulation Fasteners

Bill of Materials

Handout

Final Drawings

Full Draft

Characteristic Dimensions Housing

(21x8x8)in box 1in thick

Insulation 6x(19x6x1)in 2 milled sections

Specimen 18in long 1in diameter

Heater 3/8in diameter 1¼in length

Cooling Jacket 1in diameter 1.24in depth

Thermocouples 5 total Begin 3¼in down

spec. 3in apart

Cross SectionsHot Side Cold Side

Calculations

Needed Values Proper length for rod

Manageable specimen Reasonable time for Steady State

Thermal Conductivity “Bread and Butter” of experiment Derived from Fourier’s Law

Estimated Temperature Ranges Use k-values for plausible samples Stay within a reasonable range

Heat into the system (using potential materials) Heat loss (for safety and efficency)

Rod Length vs. Steady State Time

Approximations

Fourier’s Law

q=Heat Flux (W/m^2)Ti=Initial Temperature (K)Tf=Initial Temperature (K)R= Thermal Resistivity (K*m^2/W)A=Surface Area (m^2)Q=Heat (Watts)r=Radius of Rod (m)x=location (m)

k=Thermal Conductivity (W/m*K)

Estimated Temperature Ranges

∆x=10” r=1” Q=110 W

∆T(Al)=82.5K ∆T(Cu)=35.5K ∆T(Br)=119.9K

k(Al)=167 W/m*K k(Cu)=388 W/m*K k(Brass)=115 W/m*K

10”

Lab View HMI Example

Temperature Data Example

0 50 100 150 200 250 300 350 400 4500

2

4

6

8

10

12

Temperature vs. Time

Series1Series2Series3Series4Series5

Time

Tem

pera

ture

140.321123.12898.78975.45156.266

T1T2T3T4T5

Current Temperature

2 4 6 8 10 12 14 160

20

40

60

80

100

120

140

160

Temperature vs. Distance

T1T2T3T4Linear (T4)T5

Distance

Tem

pera

ture

Heat Source

Q= V*I = 110W

I=Current (amps)R=Resistance of heater (Ω)V=Volts (Volt)P=Power (Watts)Q=Heat (Watts)

For Potential Power Source and HeaterV=23Volts (variable)I=5amps (constant)*Assuming all electrical power is transfer to heat

Heat Loss

 l=length (m)w=width (m)t=thickness (m)k=Thermal Conductivity (W/(mK))Tin= Temperature on the inside surface of the insulation (K)Tsur=Temperature of the outside surface of the insulation (K)*Assuming whole inner surface is at one temperature, and the entire outer surface is at room temperature (293 K)

Inner surface temperature of 400KOuter surface temperature of 293KDimensions (19”x6”x2.5”)Material: Calcium Silicate k=.073W/(m*K)

Heat Lost (Q)= 9.04 W This calculation is <2% of the max energy

mentioned in the PRP (500W)

Estimated Heat Loss

Risk AssessmentTesting ProceduresProduction Timeline

Remaining Handouts