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A furnace wall is constructed of an inner layer of 10 mm of material A with...

A furnace wall is constructed of an inner layer of 10 mm of material A with kA = 20W/mK, 20 mm of material B with kB = 1.5 W/mK, a middle layer of 30 mm of material C with kC=3.0 W/mK) , and an outer layer of 40 mm of material D (kD=300 W/mK) . The temperature of inside wall is 1000 K and the temperature of outer layer is 350 K. The temperature and convection coefficient of hot air inside furnace are 1100 K and 100 W/m2K, while the temperature and convection heat transfer coefficient of the ambient air outside the furnace are 300K and 25 W/m2K.

1) Calculate the heat flux transferred from the furnace through the wall to surrounding.

2)Calculate the temperature at the interface between material B and material C

3) If material B is changed to material E with kE= 15W/mK with a thickness of 15mm.Calculate the heat loss from furnace to surrounding. Comment on the effectiveness of material B and material E.

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