1. A counter flow, 1-1 shell and tube heat exchanger is used to heat milk using hot water. Milk enters the heat exchanger at 4°C with a flow rate of 500 kg/h. The inlet and exit temperatures of hot water flowing at a rate of 807 kg/h are 90°C and 50°C, respectively. The heat exchange area is 9 m². The convective heat transfer coefficients on milk and hot water sides are 160 W/m²K and 1000 W/m?K, respectively. a) Assuming thermal resistance of tube wall is negligible, calculate the overall heat transfer coefficient i. before any fouling occurs ii. after fouling with a fouling factor of 0.0008 m2 K/ W occurs on the surfaces of the tubes on milk side b) Calculate the exit temperature of milk in both cases c) Does the milk temperature reaches to the desired pasteurization temperature of 72°C in both cases Data: cp, milk = 3930 J/kg K cp, water = 4180 J/kg K

1. A counter flow, 1-1 shell and tube heat exchanger is used to heat milk using hot water. Milk enters the heat exchanger at 4°C with a flow rate of 500 kg/h. The inlet and exit temperatures of hot water flowing at a rate of 807 kg/h are 90°C and 50°C, respectively. The heat exchange area is 9 m². The convective heat transfer coefficients on milk and hot water sides are 160 W/m²K and 1000 W/m?K, respectively. a) Assuming thermal resistance of tube wall is negligible, calculate the overall heat transfer coefficient i. before any fouling occurs ii. after fouling with a fouling factor of 0.0008 m2 K/ W occurs on the surfaces of the tubes on milk side b) Calculate the exit temperature of milk in both cases c) Does the milk temperature reaches to the desired pasteurization temperature of 72°C in both cases Data: cp, milk = 3930 J/kg K cp, water = 4180 J/kg K

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 10.46P

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