heat transfer lab 1

7/25/2019 Heat Transfer Lab 1

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Heat Transfer MECE 3930U

Lab 1:

Heat Conduction Unit

Lab Group:

Date of Lab: January !" 01#

Due Date: $ebruary %" 01#

&a'e (tudent )D (i*natureEric McCor'ic+ 100! 303#Matt,e- Le.ins 100! 03/#Ty er Le-is 100! !Cody 2a ton 100! 10#3


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Contents)ntroduction

T,eoretica 4ac+*round and 5pp ication

E6peri'enta Unit and 7rocedure

E8uip'ent

7rocedure

esu ts and Discussion

E8uations

Tabu ated DataConc usion

&o'enc ature

eferences

5ppendi6


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1

IntroductionT,e ob ecti.e of t,is ab is to in.esti*ate i'portant aspects of conduction ,eat transfer

Measure'ents -i be 'ade to e6p ore t,e properties of t,er'a conducti.ity and te'perature

c,an*es for bot, inear and radia conduction cases

T,er'a conduction is described as t,e transfer of ener*y fro' 'ore ener*etic partic es

to ess ener*etic partic es due to t,e partic es interactions -it, one anot,er )n a stationary

'ediu'" t,is causes a te'perature *radient to e6ist in t,e 'ediu' Heat transfer e6ists in

.irtua y a en*ineerin* app ications" t,erefore" it is i'portant to ,a.e an understandin* of t,e

'ec,anics in.o .ed -it, t,er'a conducti.ity

Theoretical Background and ApplicationT,er'a conduction is t,e transfer of ener*y" in t,e for' of ,eat" fro' areas of ,i*,er

ener*y concentration to areas of o-er concentration T,e 'et,ods in -,ic, ener*y transfers

.ary dependin* on t,e p,ysica state of t,e 'ediu' in.o .ed $or *aseous and i8uid 'ediu's"

t,e transfer of ener*y is due to co isions and diffusion of 'o ecu es durin* rando' 'otion $or

so id 'ediu's" t,e transfer of ener*y is due to .ibrations in t,e 'o ecu ar attice and by ener*y

transported by free e ectrons 'o.in* fro' one 'o ecu e to anot,er

$ourier;s a- of ,eat conduction describes t,e re ations,ip bet-een t,e rate of ,eat

conduction and .arious properties of t,e 'ediu' as:

Rateof Heat Conduction ( Area )(Tempurature Difference )

Thickness

T,er'a conducti.ity is t,e abi ity for a 'ateria to conduct ,eat T,is .ariab e" denoted as k " is

dependent on t,e 'ediu' on -,ic, t,e t,er'a conduction is occurrin* 4y usin* t,er'a

conducti.ity" t,e e8uation for t,e rate of ,eat condition is:

Q cond = kA dT dx


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Heat conduction occurs in t,e direction of decreasin* te'perature Due to t,is" t,e

te'perature *radient"dT dx " beco'es ne*ati.e -it, t,e positi.e 6


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3

Experimental Unit and Procedure

Equipment

T,e e8uip'ent in.o .ed -it, t,e co'p etion of t,is aboratory is as fo o-s:

T,er'a Conduction Unit

1 Heat conduction in 3 .arious p ane -a sHeat conduction in a cy inder

3 Contro and disp ay unit/ Data cab e! 7o-er cab e# Coo in* -ater feed

2ater return syste'% Mains po-er


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/

T,ree Types of )nserts

1 4rass" !'' Dia'eter" 30'' Len*t,(tain ess (tee 1 /30!" !'' Dia'eter" 30'' Len*t,

3 4rass" 1!'' Dia'eter" 30'' Len*t,


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!

Cy indrica Heat Conduction Unit

1 )nsu ated ,ousin*Dis+

3 Heater / Coo er =copper pipe>! (i6 te'perature 'easurin* points

Procedure

T,e ,eat conduction unit -as setup as s,o-n in $i*ure 1 of t,e aboratory 'anua Co d

-ater -as supp ied to t,e unit usin* t,e ,oses )nsert 1 -as insta ed and t,e coo in* -ater f o-

rate -as ad usted to appro6i'ate y 1+*?, to ensure t,at a ,eater po-er of 90 2 at a te'perature

difference of 90@C T,e unit -as turned on and t,e te'perature drop -as set usin* t,e po-er

settin* on t,e contro and unit disp ay T,e unit -as a o-ed to reac, a steady state condition"

t,is occurs -,en t,e indi.idua 'easurin* points are stab e and unc,an*in* T,e po-er supp ied

to t,e unit and t,e te'perature at t,e indi.idua 'easurin* points -ere recorded T,is process

-as repeated t,ree 'ore ti'es for t,e t-o ot,er inserts" and once a*ain for t,e radia unit


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#

Results and Discussion

Equations

Heat conduction in a -a is described by $ourier;s La-" -,ic, is e6pressed as:

Q cond = kA dT dx

$or t,e co'posite -a s,o-n in $i*ure # of t,e ab 'anua " t,e ,eat f o- is described as:

1st Layer: Q= K 1 A(T 1 T 2 )

L1

nd Layer: Q= K 2 A(T 2 T 3 )

L2

&t, Layer: Q= K n A(T n T n+1 )

Ln

T,e ,eat f o- fro' t,e o.era difference is found by t,e fo o-in* e8uation:

Q= A(T 1 T n+1 ) L1k 1

+ L2k 2

+ Lnk n


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Tabulated Data

Tab e 1: Heat Conduction in a 7 ane 2a =)nsert A1 -it, 3 Te'perature Measure'ent 7oints>

Te'perature

Measure'ent

7oints

Materia of Measure'ent

(ection

4rass 4rass 4rass

Dia'eter =''> ! ! !T,eoretica Conducti.ity at

0@C =-?'B >

113 113 113

Measured Heatin* 7o-er =2> #3 !Distance

=''>

Measured

Te'perature

=@C>

Te'p Difference in

= >

T,er'a Conducti.ity

=2?'B >

1 < T 1 = 73.5 <

Te'perature

Measure'ent7oints


(ection

4rass (tain ess

(tee

4rass

Dia'eter =''> ! ! !T,eoretica Conducti.ity at

0@C =-?'B >

113 1! 113

Measured Heatin* 7o-er =2> //Distance

=''>

Measured

Te'perature

=@C>

Te'p Difference in

= >

T,er'a Conducti.ity

=2?'B >

1 < T 1 = 103.8 <


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%

10 T 2 = 102.5

3 0 T 3 = 98.6

Contact 7oint

1

! T 4 =

Contact 7oint !! T 6 =

#0 T 7 = 28.6

% 0 T 8 = 26.6

9 %0 T 9 = 23.5


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9

Tab e 3: Heat Conduction in a 7 ane 2a =)nsert A3 -it, &o Te'perature Measure'ent 7oints>

Te'perature

Measure'ent

7oints


(ection

4rass 4rass 4rass

Dia'eter =''> ! 1! !T,eoretica Conducti.ity at

0@C =-?'B >

113 113 113

Measured Heatin* 7o-er =2> ! 1Distance

=''>

Measured

Te'perature

=@C>

Te'p Difference in

= >

T,er'a Conducti.ity

=2?'B >

1 < T 1 = 85.3 <

Te'perature

Measure'ent

7oints


(ection

4rass

Dia'eter =''> 1 ?110T,eoretica Conducti.ity at

0@C =-?'B >

113

Measured Heatin* 7o-er =2> #/Distance

=''>

Measured

Te'perature

=@C>

Te'p Difference in

= >

T,er'a Conducti.ity

=2?'B >

1 < T 1 = 46.8

heat transfer lab 1

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