One end of a copper rod 30 cm long is held at 200°C, and the other end is held at 93°C. The heat transfer coefficient in between is 17 W/m^2 K. If T = 38°C and the diameter of the rod is 1.25 cm, what is the net heat removed by the air around the rod?
First obtain a solution for θ (ξ) using boundary conditions that specify the temperatures at
X=0 and x =L: T(0) = 200°C and T(0.3m) = 93°C
θ (ξ) = cosh (mLξ) - 0.9902sinh (mLξ)
Air at-10°C flows over a smooth, sharp edged, almost flat, aerodynamic surface at 240 km/hr. The surface is at 10°C. Find (a) the approximate location of the laminar turbulent transition; (b) the overall h for a 2 m chord; (c) h at the trailing edge for a 2m chord; (d) δ and h at the beginning of the transition region. [Answer δxt = 0.54 mm]
Assume the transition occurs at Re = 4 x 105
(a) 0.0795, (b) 148 W/m^2*K, (c) 134 W/m^2*K, (d) h = 57 W/m^2*K, and δ = 0.62 mm at the beginning of the transition region just before the flow becomes turbulent.