A concentric tube heat exchanger is used to cool lubricating oil for a large diesel engine. The inner tube is constructed of 2 mm wall thickness stainless steel, having thermal conductivity 16 W/m K. The flow rate of cooling water through the inner tube (radius = 30 mm) is 0.3 kg/s. The flow rate of oil through the tube (radius = 50 mm) is 0.15 kg/s. Assume fully developed flow, if the oil cooler is to be used to cool oil from 90°C to 50°C using water available at 283K. The overall heat transfer coefficient is 21.9 W/(m2K). Calculate the length of the tube required for parallel (co-current) flow, and the length of the tube required for counter-current flow. The average heat capacity for oil is 2.131 kJ/(kgK) and for the water 4.178 kJ/(kgK).

A concentric tube heat exchanger is used to cool lubricating oil for a large diesel engine. The inner tube is constructed of 2 mm wall thickness stainless steel, having thermal conductivity 16 W/m K. The flow rate of cooling water through the inner tube (radius = 30 mm) is 0.3 kg/s. The flow rate of oil through the tube (radius = 50 mm) is 0.15 kg/s. Assume fully developed flow, if the oil cooler is to be used to cool oil from 90°C to 50°C using water available at 283K. The overall heat transfer coefficient is 21.9 W/(m2K). Calculate the length of the tube required for parallel (co-current) flow, and the length of the tube required for counter-current flow. The average heat capacity for oil is 2.131 kJ/(kgK) and for the water 4.178 kJ/(kgK).

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.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.48P

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