Q2. An automotive radiator that is a compact cross-flow water-to-air heat exchanger with both fluids (air and water) unmixed (see the figure). Hot water enters the tubes at 90C at a rate of 0.6kg/s and leaves at 60C (assume: water cpm=4.2kJ/kgK ). Air flows across the radiator through the interfin spaces and is heated from 20C to 40C. The overall heat transfer coefficient Ui of this radiator based on the inner surface area is 3341W/m2C. The internal diameter of tubs is 0.5cm and length 65cm in a closely spaced plate-finned matrix. Determine: a) The correction factor and the log mean temperature b) The number of tubes required for the heat exchanger