A cylindrical heat exchanger is used to warm up a stream of 0.15 Kg s-' cold air from a temperature of 200 K to 300 K, after which it is released into the atmosphere. The air enters and leaves the heat exchanger through a pipe with a diameter of 5 cm. The heat exchanger is of a "Shell and tube design" as shown below and the air flows through the inside of the tubes. The internal diameter of the shell is 30 cm. There are 40 tubes each with a diameter of 1 cm in the heat exchange. It can be assumed that there is no friction in the system. The only change in the gas density occur inside the tubes, elsewhere, the gas can be considered incompressible. The density of the air at 300 K is 1.23 Kg m-3. The viscosity of air at 200 K is 1.1 x 10-5 kg m-1 s-l; at 300 K it is 1.8 x10-5 kg m-' s-1. Water of enters the heat exchanger at 350 K and leaves at 320 K. a) Suggest suitable material for the tubes and shell for water to be sea water or feed water. b) Comment of the effect of fouling on the performance of the heat exchanger considered.

A cylindrical heat exchanger is used to warm up a stream of 0.15 Kg s-' cold air from a temperature of 200 K to 300 K, after which it is released into the atmosphere. The air enters and leaves the heat exchanger through a pipe with a diameter of 5 cm. The heat exchanger is of a "Shell and tube design" as shown below and the air flows through the inside of the tubes. The internal diameter of the shell is 30 cm. There are 40 tubes each with a diameter of 1 cm in the heat exchange. It can be assumed that there is no friction in the system. The only change in the gas density occur inside the tubes, elsewhere, the gas can be considered incompressible. The density of the air at 300 K is 1.23 Kg m-3. The viscosity of air at 200 K is 1.1 x 10-5 kg m-1 s-l; at 300 K it is 1.8 x10-5 kg m-' s-1. Water of enters the heat exchanger at 350 K and leaves at 320 K. a) Suggest suitable material for the tubes and shell for water to be sea water or feed water. b) Comment of the effect of fouling on the performance of the heat exchanger considered.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter10: Heat Exchangers

Section: Chapter Questions

Problem 10.32P

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