Download - Shell and Tube Heat Exchanger 1
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SHELL AND TUBE
HEAT EXCHANGER
Contents
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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
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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 $ound in Appendix !*
Theory
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The shell and tu'e heat exchan(er is the most commonly used heat exchan(er in
industry* This is 'ecause there are seeral 'ene$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$$icients $or the tu'es are .no)n as the tu'es are made $rom a
standard construction material* The maority o$ the resistance to heat trans$er
occurs at the tu'es/ 'oth inside and outside 1 as the steam $lo)s inside the
tu'es/ the condensin( steam usually displays less resistance than )ater and
hence the main resistance is the outer one* This is sho)n 'y the e0uation
Q'=UOAO TLM(UiA i TLM)
8here
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And
8hen UO is calculated/ insertin( alues into the a'oe e0uation )ill isolate 4
un.no)ns* In the case o$ $orced conection/ $ilm coe$$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
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Experimental Apparatus
The experiment )as set up as $ollo)s
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Shell and Tube Heat
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Experimental Method
The am'ient pressure o$ 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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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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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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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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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*
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"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
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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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h=hcA T= (1050 ) ( )0.00274321.2192 ) (24.6 )=2713.98
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