3.48 A thin electrical heater is wrapped around the outer sur- face of a long cylindrical tube whose inner surface is maintained at a temperature of 5°C. The tube wall has inner and outer radii of 25 and 75 mm, respectively, and a thermal conductivity of 10 W/m K. The thermal con- tact resistance between the heater and the outer surface of the tube (per unit length of the tube) is R = 0.01 m K/W. The outer surface of the heater is exposed to a fluid with To = -10°C and a convection coefficient of h= 100 W/m² K. Determine the heater power per unit length of tube required to maintain the heater at T, = 25°C.

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a bur…