Question 1 A furnace wall consisting of 0.20 m of fire clay brick, 0.15 m of kaolin, and a 0.05-m outer layer of masonry brick is exposed to furnace gas at 1250 K with air at 298 K adjacent to the outside wall. The inside and outside convective heat transfer coefficients are 55 and 10 W/m2 K, respectively. Determine the heat loss per square meter of wall and the temperature of the outside wall surface under these conditions. [15 Marks] Question 2 Supposed that the outside temperature of the masonry brick in question 1 cannot exceed 350 K, by how much must the thickness of kaolin be to maintain the same heat flux requirement? [10 Marks] Question 3 You are instructed to design a furnace wall capable of transmitting a maximum heat flux of 550 W/m2. The inside and outside wall temperatures are to be maintained at 1100C and 200C, respectively. Two brick materials are available to line the walls of the furnace. Both have dimensions 22 cm x 11 cm x 7 cm. One material has a thermal conductivity (k) of 0.76 W/m K and a maximum usable temperature of 810C and the other with a k of 1.63 W/m K and a maximum usable temperature of 1300C. Bricks made of each material cost the same amount and may be laid in any manner. Determine the most economical arrangement of bricks. [10 Marks] Question 4 A very long solid piece of rectangular material of 4 mx 3 m has its top face maintained at a constant temperature of 800 K and its left face at 298 K. The bottom face and right face are exposed to an environment at 200 K and the thermal conductivity of the material is 10 W/m.K. Use a grid size of Ax= Ay = 0.5 m and calculate the steady-state temperatures of the various nodes. [20 Marks]