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Effectiveness/NTU Curves for Tubular Heat Exchangers
Definitions
)(
)()(
)()(
)/()(
))/(/()(
)(
)(
)//()(
))/(/()(
)//()(
2
2
fluidscoldandhotofestemperaturentrybetweendifference
ratecapacitylowerwithfluidofchangeetemperaturesseffectiven
Cm
AUunitstransferofnumberNTU
mtransferheatforareasurfaceA
KmWtcoefficientransferheatoverallU
ratecapacityheathigher
ratecapacityheatlowerR
KWratecapacityheatCm
KkgJcapacityheatspecificC
skgrateflowmassm
lower
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Effectiveness/NTU Curves: parallel flow
0
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NTU
Effectiveness
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Effectiveness/NTU Curves: counter flow
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NTU
Eff
ectiveness
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Effectiveness/NTU Curves:
one she ll pass and an even number of tube passes
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NTU
Ef
fectiveness
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Effectiveness/NTU Curves:
two shell passes and twice an even number of tube passes
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0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
NTU
Ef
fectiveness
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Effectiveness/NTU Curves:
cross flow - both fluids unm ixed
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NTU
Effectiveness
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Effectiveness/NTU Curves:
crossflow - lower capacity fluid mixed
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NTU
Effe
ctiveness
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Copyright: Glasgow College of Nautical Studies Page 8 of 8
Effectiveness/NTU Curves:
crossflow - higher capacity fluid mixed
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0.8
0.9
1
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
NTU
Effe
ctiveness