A tubular heater of the counterflow type is used to heat 1.26 kg/s of fuel oil (cp = 3.14 kJ/kg K) from 10 C to 26.7 C. Heat is supplied by means of 1.51 kg/s of water which enters the heater at 82 C....

A tubular heater of the counterflow type is used to heat 1.26 kg/s of fuel oil (cp = 3.14 kJ/kg K) from 10C to 26.7C. Heat is supplied by means of 1.51 kg/s of water which enters the heater at 82C. (a) Derive an equation relating the temperatures of oil and water at any section of the heater. (b) Determine the necessary surface area if the overall heat transfer coefficient is 1.135 kW/m²
K.