A. A scale model of an aeroplane wing section is tested in a wind tunnel at M = 1.5. The air pressure and temperature in the test section are 20 kPa and – 30°C, respectively. If the wing section is to be kept at an average temperature of 60°C, determine the rate of cooling required. The wing model can be approximated by a fl at plate of 0.3 m length in the fl ow direction.
B. For a heat flux (Q/A)0 = 4 ¥ 106 W/m2 and the following material properties, estimate the steady-state ablation velocity and the fraction Qc/Q0 in 30s. At what distance x is the temperature equal to 60°C? In 30 show much material has ablated? Given: r = 1602 kg/m3, c = 1256 J/kg K, k = 0.86 W/m K, F = 9300 J/kg, Tm = 1650°C and T• = 20°C.
