1. Engine oil (cp = 2100 J/kg-°C) is to be heated from 20 °C to60 °C at a rate of 0.3 kg/s in a 2-cmdiameter thin-walled coppertube by condensing steam outside at a temperature of 130 °C (hfg =2174 kJ/kg).
a. For an overall heat transfer coefficient of 650 W/m2 -°C,determine the rate of heat transfer and the length of tube requiredto achieve it. Determine also the rate of steam condensation, inkgsteam/sec. (Ans: 25.2 kW; 7.0 m)
b. What would the tube length have to be if we wanted to heatthe oil to 100 °C in the same 2-cm diameter tube and at the sameflow rate? How about heating to 120 °C?
