Question

Consider a cube of density, specific heat, and thermal conductivity of 2700 kg/m3, 0.896 kJ/kg-K, and 204 W/m-K, respectively. The cube is 5 cm in length, and is initially at a temperature of 20 oC. For t>0, two of the boundary surfaces are insulated, two are subjected to uniform heating at a rate of 10,000 W/m2, and two dissipate heat by convection to an ambient temperature of 20 oC, with a heat transfer coefficient of 50 W/m2-K.

Assuming lumped capacitance is applicable, determine the time required for the cube to come to within 5 degrees of its steady-state temperature.

Answer 1