Question: an aluminium tube carrying a hot liquid at 112c has...
An aluminium tube carrying a hot liquid at 112C has 12 integrally machined longitudinal fins on its outer surface. The tube’s inner and outer radii are 14 and 19 mm, and its total length is 260 mm, while the fins’ height is 21 mm and their thickness is 2 mm. Air at 22C flows over the fin surface, providing an approximately uniform convection heat transfer coefficient of 28 W/m2 C, and the heat transfer coefficient of the hot liquid inside the tube is 44 W/m2 C. The thermal conductivity of aluminium is 200 W/m C.
(a) State the assumptions and draw a clear sketch showing the geometry, boundary conditions and equivalent thermal circuit.
(b) Calculate the thermal resistance of the entire fin system.
(c) Calculate the fin’s heat transfer rate.