A shell-and-tube heat exchanger (one shell pass, multiple tube passes) is to be used to cool engine oil of 100 kg/s entering the shell side at 370 K and leaving at 338 K. The corresponding convection coefficient on the tube surface and the LMTD correction factor of the heat exchanger are known to be ho=10867 W/m2K and F=0.99, respectively. The condenser will be supplied with cooling water that enters the tubes at 280 K and is to exit the tubes at 320 K. Thin walled tubes of 30 mm diameter are specified and the mean velocity of water flow through the tubes is to be maintained at 1.42 m/s. Find: 1. i) How many tubes must be used? 2. ii) If the length of the heat exchanger is not to exceed 1.5 m, how many tube passes should be made? (for water =1000O kg/m3. c,=4000 J/kgK, µ=959x10-6 Ns/m², k=0.606 W/mK, Pr=6.62 and for engine oil c,=2000 J/kgK)
Heat Exchangers
Heat exchangers are the types of equipment that are primarily employed to transfer the thermal energy from one fluid to another, provided that one of the fluids should be at a higher thermal energy content than the other fluid.
Heat Exchanger
The heat exchanger is a combination of two words ''Heat'' and ''Exchanger''. It is a mechanical device that is used to exchange heat energy between two fluids.
A shell-and-tube heat exchanger (one shell pass, multiple tube passes) is to be used to cool engine oil of 100 kg/s entering the shell side at 370 K and leaving at 338 K. The corresponding convection coefficient on the tube surface and the LMTD correction factor of the heat exchanger are known to be ho=10867 W/m2K and F=0.99, respectively. The condenser will be supplied with cooling water that enters the tubes at 280 K and is to exit the tubes at 320 K. Thin walled tubes of 30 mm diameter are specified and the mean velocity of water flow through the tubes is to be maintained at 1.42 m/s.
Find:
- i) How many tubes must be used?
- ii) If the length of the heat exchanger is not to exceed 1.5 m, how many tube passes should be made?
(for water =1000 kg/m3, cp=4000 J/kgK, µ=959x10-6 Ns/m2, k=0.606 W/mK, Pr=6.62 and for engine oil cp=2000 J/kgK)
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