In: Mechanical Engineering
A counterflow, concentric tube heat exchanger used for engine cooling has been in service for an extended period of time. The heat transfer surface area of the exchanger is 5 m2, and the design value of the overall convection coefficient (without any fouling) is 38 W/m2K. During a test run, engine oil flowing at 0.1 kg/s is cooled from 110oC to 66oC by water supplied at a temperature of 25oC and a flow rate of 0.18 kg/s. Determine whether fouling has occurred during the service period. If so, calculate the fouling factor, R”f (m2K/W). Specific heat of engine oil is 2166 J/kgK, and water is 4178 J/kgK.
What is R”f = x 10-3 m2K/W?