Question

[20] SECTION B (Attempt any one Question) a) A turbine blade 6 cm long and having a cross sectional area 4.65 cm and perimeter 12 cm is made of stainless steel (k=23.3 W/mK). The temperature at the root is 500 °C. The blade is exposed to a hot gas at 870 °C. The heat transfer coefficient between the blade surface and gas is 442 W/mK. Determine the temperature distribution and rate of heat flow at the root of the blade. Assume the tip of the blade to be insulated. b) The hot combustion gases of a fumace are separated from the ambient air and its surrounding, which are at 20°C, by a brick wall 0.5 m thick. The brick has a thermal conductivity of 5 W/mK and a surface emissivity of 0.6. Under steady-state conditions an Page no. 1 of 1 outer surface temperature of 120°C is measured. Free convection heat transfer to the air adjoining the surface is characterized by a convection coefficient of 15 Wim K What is the brick inner surface temperature!

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Answer 1

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answer 7 (a)

Question - 7 Labem - 0.006 m A = 4.65 cm² = 4-658104 28.3 Wlmk 500°c To = 870°c. T 442 Wim²K P= 12am 0.012 m

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