3) Determine the heat transfer through the composite wall shown in the figure below .Take the conductives of A, B, C, D & E as 50, 10, 6.67, 20& 30 W/mK respectively and assume one dimensional heat transfer. Take of area of A =D= E =1m' and B=C=0.5 m² .Temperature entering at wall A is 800 °C and leaving at wall E is 100 °C.

heat transfer  Adjacent vertical quadrilaterals arranged as in the figure below are black bodies. Area 1 and Area 2 are 800K and 500K, respectively. Calculate the radiative heat transfer (q12) between the two surfaces.

A7

An experiment to measure the thermal conductivity of food formulations was carried out by measuring the surface temperature of the food formulations which were formed into flat plates with a thickness of 10 mm. It is found that at steady-state conditions, there is a temperature difference of 40 ° C between the two surfaces, the heat transfer rate per unit area of 4700 W / m2 is measured near the center of the two surfaces. Calculate: the thermal conductivity of the product, = AnswerW / m ° C