shell and tube heat exchanger 1

7/24/2019 Shell and Tube Heat Exchanger 1

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SHELL AND TUBE

HEAT EXCHANGER

Contents

1


2/18

Introduction 3

Theory 4-5

Experimental Apparatus 6

Experimental Method 7

Results -!!

"iscussion !#

Conclusions !3

Re$erences !4

%ist o$ &ym'ols !5

Appendices 16-17

Introduction

2


3/18

The 'asic premise o$ a heat exchan(er is to trans$er heat 'et)een t)o streams

)ithout the streams comin( in direct contact* A shell and tu'e heat exchan(er

consists o$ a series o$ lon( tu'es enclosed in a cylindrical shell* +ne $luid $lo)s

throu(h the inner tu'es )hilst a second $luid $lo)s throu(h the shell in the space

'et)een the tu'es and the inside o$ the shell* ,eat trans$er is achieed throu(h

conection on 'oth sides o$ the inner tu'e as )ell as conduction throu(h the

tu'es*

The aim o$ this experiment )as to calculate oerall heat trans$er coe$$icients

throu(h the use o$ experimental data* This )ould allo) us to calculate shell and

tu'e side coe$$icients and these )ould 'e compared to .no)n alues $romliterature*

The materials used in this experiment can 'e $ound in Appendix !*

Theory

3


4/18

The shell and tu'e heat exchan(er is the most commonly used heat exchan(er in

industry* This is 'ecause there are seeral 'ene$its )hich ma.e it more ia'le

$or use oer other types o$ exchan(er* These include the $act that the layout

allo)s $or a (reater sur$ace area )hilst usin( a small olume as )ell as 'ein(

'ene$icial $or pressure operation* As )ell as this/ the construction o$ the heat

exchan(er can use a )ide ran(e o$ materials usin( )ell esta'lished $a'rication

techni0ues/ and also the $act that it can 'e cleaned easily )hen $oulin( occurs*

"eterminin( the oerall heat trans$er coe$$icient is one o$ the most important

and usually the most uncertain aspect in the analysis o$ heat exchan(ers* This

coe$$icient accounts primarily $or all o$ the conectie and conductieresistances/ $or $luids separated 'y a )all or tu'e 1 as )ell as this it also ta.es

into account thermal resistances cause 'y $oulin(*

The heat load 2 can 'e determined $rom either the increase in )ater

temperature or the rate o$ condensation o$ steam* This is (ien 'y the e0uation

Q'=m'Cp (TCOTCI)=m'cfg

,eat trans$er coe$$icients $or the tu'es are .no)n as the tu'es are made $rom a

standard construction material* The maority o$ the resistance to heat trans$er

occurs at the tu'es/ 'oth inside and outside 1 as the steam $lo)s inside the

tu'es/ the condensin( steam usually displays less resistance than )ater and

hence the main resistance is the outer one* This is sho)n 'y the e0uation

Q'=UOAO TLM(UiA i TLM)

8here

4


5/18

And

8hen UO is calculated/ insertin( alues into the a'oe e0uation )ill isolate 4

un.no)ns* In the case o$ $orced conection/ $ilm coe$$icients $or tur'ulent $lo)

o$ tu'ular sur$aces is proportional to the elocity o$ the $luid raised to the po)er

o$ 9** This is sho)n 'y the e0uation

&u'stitution o$ the t)o e0uations a'oe (ies us the e0uation

This e0uation (ies us a strai(ht line (raph $or1

UO s1

W0.8 1 this is

.no)n as a 8ilson :lot* The ;-axis intercept o$ this (raph )ill (ie the

com'ined resistances o$ the steam $ilm/ exchan(er )all and the $oulin( layers*

All o$ this allo)sh

i to 'e calculated

5


6/18

Experimental Apparatus

The experiment )as set up as $ollo)s

6

Shell and Tube Heat


7/18

Experimental Method

The am'ient pressure o$ the room )as ta.en prior to the experiment 'ein(

carried out* The coolin( )ater isolation ale )as turned on/ $ollo)ed 'y the

ale at the 'ottom o$ the )ater $lo)meter 1 this allo)ed the maximum

$lo)rate o$ )ater to 'e $ound* The thermocouples T! and T# )ere s)itched on*

The condensate collect ale )as closed< the condensate return ale )as

opened and the steam isolation ale )as turned on until the steam pressure

reached a re0uired pressure* !5 minutes )ere allo)ed $or the exchan(er to reach

e0uili'rium*

Initially a 'uc.et )as $illed )ith )ater and )ei(hed on a di(ital 'alance 1 this

)as then placed under )here the steam condensate exit the exchan(er* The

condensate collect ale )as opened and the condensate return ale closed/

allo)in( )ater to trael into the 'uc.et 1 alues $rom the thermocouple/

pressure (au(e and $lo)rate )ere measure eery minute $or 5 minutes* +nce

completed/ the 'uc.et )as )ei(hed a(ain to measure ho) much condensate had

'een produced* This procedure )as repeated $or 5 di$$erent $lo) rates*

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8/18

Results

Experimental dataR=> R=> R=> R=> R=>

! # 3 4 5

8ei(ht o$ 'uc.et at

end o$ run 2.(4*376 4*#7# 4*695 4*# 4*675

8ei(ht o$ 'uc.et at

start o$ run 2.(

2Cali'rated

9 9 9 9 9

8ater outlet

temperature 2?C @

9 min

4# 43 4# 49 47

8ater outlettemperature 2?C @

! min

49 4! 3 4 4

8ater outlet

temperature 2?C @

# min

4! 3 44 4 5!

8ater outlet

temperature 2?C @

3 min

49 3 43 46 4

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9/18

8ater outlet

temperature 2?C @

4 min

49 3 44 45 47

8ater inlet

temperature 2?C @9 min !5 !7 !5 !5 !5

8ater inlet

temperature 2?C @

! min

!5 !7 !5 !5 !5

8ater inlet

temperature 2?C @

# min

!6 !7 !6 !6 !6

8ater inlet

temperature 2?C @

3 min

!7 !7 !6 !6 !7

8ater inlet

temperature 2?C @

4 min

!7 ! !7 !7 !7

&team pressure 2'ar

( @ 9 min!*5 9*5 !*! #*3 #*6

&team pressure 2'ar

( @ ! min!*35 9*4 !*95 #*35 #*35

&team pressure 2'ar

( @ # min9* 9*4 ! !*55 !*75

&team pressure 2'ar

( @ 3 min9*7 9*3 9* !*#5 !*4

&team pressure 2'ar

( @ 4 min9*5 9*3 9* ! !*3

8ater $lo)rate

2litreBmin# #6 #4 ## #9

Interpreted dataR=> R=> R=> R=> R=>

! # 3 4 5

Mean )ater inlet

temperature Tin2?C !6 !7*# !5* !5* !6

Mean )ater outlet

temperature Tout2?C49*6 49*# 4#*4 45* 4*4

&team pressure :

2'ar a'solute!* !*3 !* #*6 #*

Rate o$

condensation 2.(Bs9*9!3 9*9!7 9*9!# 9*9# 9*9!5

Mean )ater

temperature Ta2?C#*3 #*7 #!*! 39* 3#*#

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10/18

Temp* chan(e o$

)ater 2Tout- Tin 2?C#4*6 #3 #6*6 39 3#*4

Physical properties

data

R=> R=> R=> R=> R=>

! # 3 4 5C:o$ )ater @ Ta

2B.(*D4!9*3# 4!9*4 4!!*44 4!7*!6 4!7*4

8ater density @ Tin2.(Bm3

*36 *55 *33 *33 *36

%atent heat l$(o$ sat*

steam @ : 2B.(#*#!x!96 #*#4x!96 #*#!x!96 #*!3x!96 #*!4x!96

Temp* Tsteamo$ sat*

steam @ : 2?C!!*76oC !97*54oC !!*76oC !#*3oC !3!*44oC

Calculated ResultsR=> R=> R=> R=> R=>

! # 3 4 5

8ater $lo)rate

2.(Bs9*466 9*43# 9*35 9*366 9*333

8ater heat duty 28 47#!*5! 4!537*#5 4334*3 4576*! 459#*46

&team heat duty 28 49443 37# 4#43# 4#699 4!739

Aera(e heat duty

2844!#*#5 49794*63 43!3*! 44#3*9 43496*#3

T!2de( C i*e*

entry!9#*76 9*34 !9#*6 !!3*93 !!5*44

T#2de( C i*e* exit 7*!6 67*34 76*36 3*93 3*94

T%M2de( C * 7*# * 7*#6 *35

,eat trans$er area Ao2m#

9*365 9*365 9*365 9*365 9*365

=o28Bm#D !346*46 !4#4*6# !3#*47 !#46*!5 !#9*6

Wilson plotR=> R=> R=> R=> R=>

! # 3 4 5

!B=o2m#DB8 9*99974#6 9*99979!4# 9*99975#!7 9*9999#47# 9*999#67#

!B89*

2min9*Blitre9*9*96546##7 9*97374946 9*976735 9*943454 9*9!9##!

intercept 2m#DB8 9*99935 9*99935 9*99935 9*99935 9*99935

inner diameter o$

tu'es 2m9*9#743# 9*9#743# 9*9#743# 9*9#743# 9*9#743#

outer diameter o$

tu'es 2m9*93!75 9*93!75 9*93!75 9*93!75 9*93!75

conductiity o$ tu'e

)all 28Bm*D!6*# !6*# !6*# !6*# !6*#

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11/18

tu'e )all resistance

2m#DB89*999!43#5 9*999!43#5 9*999!43#5 9*999!43#5 9*999!43#5

)ater-side $oulin(

resistance 2m#DB89*9993 9*9993 9*9993 9*9993 9*9993

steam-side $oulin(

resistance 2m#DB89*99967 9*99967 9*99967 9*99967 9*99967

!Bhi2m#DB8 9*99936463 9*9993495 9*99934975 9*99939#!3 9*999#776

!Bho2m#DB8 9*9993!35# 9*9993494 9*999#44!5 9*999#6!94 9*999#4!7!

hi28Bm#D #7!3*93 #537*46!33 #34*6## 339*73#!! 3574*5!976

ho28Bm#D 3!4!*!!995 #36*7654 336*56!574 339*7954# 4!37*!65#3

0.07 0.07 0.08 0.08 0.09 0.09 0.10

0

0

0

0

0

8I%&+> :%+T +$ !B=9 F& !B8G9*

!B=o 2m#DB8

!B89* 2min9*Blitre9*

11


12/18

"iscussion

The aim o$ this experiment )as to calculate oerall/ shell side and tu'e side heat

trans$er coe$$icients $rom experimental data and to compare these )ith alues

$rom literature* This experiment can 'e considered a success $or seeral reasons elocity o$ )ater passin( throu(h tu'es 2mBs

15


16/18


17/18

Appendix 2 Sample Calculations

All calculations are 'ased on results $rom Run !

Meanwater temperature=

42+40+41+40+40

5=40.6

||=Ambient P+P=1+0.99=1.99Steam Pressure

Rate f Cn!ensatin=

Mass Steam

Time =

4.376

240 =0.0183 "g /s

#eat $ut%=c PT&w Rate100

418048231000=41537.25W

T LM= T1 T2

ln T1ln T2=

90.3467.34

ln (90.34 ) ln(67.34)=78.28

U

0=

Q '

A0T LM

= 40704.63

0.36578.28=1424.62

TubeWa'' Resistance=

! ln (!

!i)

2"p =

0.03175ln (0.03175

0027432)

216.2 =0.00014m2(/W

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18/18

h=hcA T= (1050 ) ( )0.00274321.2192 ) (24.6 )=2713.98

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shell and tube heat exchanger 1

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