A hot brass plate is having its upper surface cooled by an impinging jet of air at a temperature of 15°C and a convection heat transfer coefficient of 220 W/m2·K. The 10-cm thick brass plate (ρ = 8530 kg/m3, cp = 380 J/kg·K, k=110 W/m·K, and α = 33.9 × 10–6 m2/s) has a uniform initial temperature of 650°C, and the bottom surface of the plate is insulated. Determine the temperature at the center plane of the brass plate after 3 minutes of cooling. 

 

Air, 15C h = 220 W/m K L= 10 cm Brass slab Insulation FIGURE P4-42