Page 1 of 1
a 1 a) The hot combustion gases of a furnace are separated from the ambient air and its surroundings, which are at 25°C,
Posted: Sun May 15, 2022 9:46 pm
by answerhappygod
- A 1 A The Hot Combustion Gases Of A Furnace Are Separated From The Ambient Air And Its Surroundings Which Are At 25 C 1 (66.35 KiB) Viewed 50 times
- A 1 A The Hot Combustion Gases Of A Furnace Are Separated From The Ambient Air And Its Surroundings Which Are At 25 C 2 (27.1 KiB) Viewed 50 times
a 1 a) The hot combustion gases of a furnace are separated from the ambient air and its surroundings, which are at 25°C, by a brick wall 0.15 m thick (Figure 1a). The brick has a thermal conductivity of 1.2 W/mK and a surface emissivity of 0.8. Under steady-state conditions an outer surface temperature of 100°C is measured. Free convection heat transfer to the air adjoining the surface is characterized by a convection coefficient of h 20 W/m².K. What is the brick inner surface temperature? (13 marks) b) Consider steady-state conditions for one-dimensional conduction in a plane wall having a thermal conductivity k = 50 W/mk and a thickness L = 0.25 m, with no internal heat generation. Determine i) the heat flux and the unknown quantity for each case; and ii) sketch the temperature distribution, indicating the direction of the heat flux. T(°C) T2(°C) dT/dx (K/m) 9(W/m) 50 -20 Case 1 2 3 70 WN 160 -80 40 (12 marks)
T1 -T2 = = 100° C E = 0.8 Tsur = 25°C rad Combustion gases Cond 9 Conv k = 1.2 W/ mK T = 25°C h = 20 W/m2K L=0.15m Air Figure la