Hey everyone, i've got a finned surface question I've got a finned wall is constructed of aluminium alloy with k = 150 W/mK. The wall thickness is 2.0 mm and the fins, with a thickness of 2.0 mm, are straight with rectangular profile. The inside of the wall is maintained at a constant temperature of 80°C and the finned section of the wall are exposed to a convection environment at 20°C with the convective heat transfer coefficient being at 8 W/m2K. The assembly will be cast from the aluminium material. You can assume that the finned wall is a 5 cm 5 cm square section. The fin pitch is 6 mm. Given the efficiency to be 98% how would i determine the length of the fin, first of all i've got the formula for fin efficiency which in its simplest form is nf = tanh (mL)/mL m = sqrt(2h/kt) I have no idea how to solve the mathematics of this to find the length, its possible i'm completely off track :( Also if i wanted to find the heat transfer rate from the ENTIRE wall how would i go about that??