Mechanical Engineering

Heat transfer

Question #5: (5 Marks) Engine oil (Cp = 2200 J/kg.K) is to be heated from 20C to 80C flows at a rate of 0.3 kg/s in a 2-cm- diameter thin walled copper tube by condensing steam outside at a temperature of 130 C (hig = 2174 kJ/kg). For an overall heat transfer coefficient of 720 W/m2.K, determine the rate of heat transfer and length of the tube required to achieve it. Steam 130C Oil 20C 0.3 kg/s 80C 130C Figure 5: Schematic for Q-5