A concentric tube heat exchanger for cooling engine oil is comprised of a thinwalled inner tube of 25 mm diameter carrying water, and an outer tube of 45 mm diameter carrying the oil. The exchanger operates in counter flow with an overall heat transfer coefficient of U= 60 W/m2 K. Flow rates are 0.1 kg/s (water) and 0.2 kg/s (oil), and the specific heats are cc = 4200 J/kgK (water) and ch =1900 J/kgK (oil). The inlet temperature of the water is Tci =30°C and the inlet temperature of the oil is Thi =100°C. (A) If the outlet temperature of the oil is Tho = 60°C, determine the total heat transfer rate q, and the outlet temperature of the water Tco. Use the LMTD method. (B) Determine the length required for the heat exchanger L. You are required to use the LMTD method.
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 concentric tube heat exchanger for cooling engine oil is comprised of a thinwalled inner tube of 25 mm diameter carrying water, and an outer tube of 45 mm diameter carrying the oil. The exchanger operates in counter flow with an overall heat transfer coefficient of U= 60 W/m2 K. Flow rates are 0.1 kg/s (water) and 0.2 kg/s (oil), and the specific heats are cc = 4200 J/kgK (water) and ch =1900 J/kgK (oil). The inlet temperature of the water is Tci =30°C and the inlet temperature of the oil is Thi =100°C. (A) If the outlet temperature of the oil is Tho = 60°C, determine the total heat transfer rate q, and the outlet temperature of the water Tco. Use the LMTD method. (B) Determine the length required for the heat exchanger L. You are required to use the LMTD method.
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