Ethylene glycol is heated from 290 K to 350 K in a rectangular duct that is 50 mm wide by 25 mm high in cross section. A constant heat flux is applied across the length of the duct. The duct is completely filled with fluid, and the flow is fully developed across the length of the run. The mass flow rate is 0.25 kg/s and the mean velocity is 0.18 m/s.
Properties of ethylene glycol: k = 0.258 W/mK, v = 6.91 x 10^-6 m^2/s, cp = 2505 J/kgK, Pr = 0.940
a) What is the heat transfer coefficient (h)?
b) What is the heat flux?
c) What surface area is required to achieve the necessary heat transfer?