Exhaust gases from a manufacturing plant are being discharged through a 10-m tall exhaust stack with outer diameter of 1 m, wall thickness of 0.2 m, and thermal conductivity of 40 W/mK. The exhaust gases are discharged at a rate of 1.2 kg/s while temperature drop between inlet and exit of the exhaust stack is 30°C, and the constant pressure specific heat of the exhaust gases is 1600 J/kg-K. On a particular day, the outer surface of the exhaust stack experiences radiation with the surrounding at 27°C, and convection with the ambient air at 27°C also, with an average convection heat transfer coefficient of 8 W/m2K. Solar radiation is incident on the exhaust stack outer surface at a rate of 150 W/m2, and both the emissivity and solar absorptivity of the outer surface are 0.9. Exhaust stack wall k-40 W/mK And Exhaust gases 9-8-09 Air, 27°C Exhaust A-8 W/m²K stack Tu-T-30°C Manufacturing plant DO K Determine the inner surface temperature of the exhaust stack (up to 1 decimal place) The inner surface temperature of the exhaust stack=[

Steam at 280° C flows in a stainless steel pipe (k = 15 W/m⋅K) whose inner and outer diameters are 5 cm and 5.5 cm, respectively. The pipe is covered with 3-cm-thick glass wool insulation (k = 0.038 W/m⋅K). Heat is lost to the surroundings at 5° C by natural convection and radiation, with a combined natural convection and radiation heat transfer coefficient of 22 W/ m2⋅K.Taking the heat transfer coefficient inside the pipe to be 80 W/ m2⋅K.Determine the rate of heat loss from the steam per unit length of the pipe and Determine the temperature decrease between the inner pipe surface and the outer insulation surface.

A 0.5-ampere current is flowing through a long electrically conducting cylindrical rod. The diameter of the rod is 6 mm, the electrical resistance of the rod is R = 2000 /m, and k =0.9 W/m K for the rod. The rod is encased in a 2-mm thick Pyrex tube and a 20°C liquid is flowing over the outer surface of the Pyrex tube. The convection heat transfer coefficient for the liquid h= 800 W/m2 . K. The interfacial conductance (contact resistance) at the interface between the rod and the Pyrex tube is h = 1200 W/m² - K. a) Compute the rate of heat generation in the rod and use it compute the volumetric rate of heat generation. b) Find the temperature drop across the interface between the outer surface of the rod and the inner surface of the Pyrex tube. c) Find the temperature at the center of the rod.

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