Q/ Steam flowing through a long, thin-walled pipe maintains the pipe wall at a uniform temperature of 500 K. The pipe is covered with an insulation blanket comprised of two different materials, A and B. The interface between the two materials may be assumed to have an infinite contact resistance, and the entire outer surface is exposed to air for which Too - 300 K and h-25 W/m? K. Calculate the total heat loss from the pipe and What are the outer surface temperatures Ts,2(A) and Ts,2(B)?

Q/ Steam flowing through a long, thin-walled pipe maintains the pipe wall at a uniform temperature of 500 K. The pipe is covered with an insulation blanket comprised of two different materials, A and B. The interface between the two materials may be assumed to have an infinite contact resistance, and the entire outer surface is exposed to air for which Too - 300 K and h-25 W/m? K. Calculate the total heat loss from the pipe and What are the outer surface temperatures Ts,2(A) and Ts,2(B)?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter11: Heat Transfer By Radiation

Section: Chapter Questions

Problem 11.50P

See similar textbooks

Similar questions

1.4 To measure thermal conductivity, two similar 1-cm-thick specimens are placed in the apparatus shown in the accompanying sketch. Electric current is supplied to the guard heater, and a wattmeter shows that the power dissipation is 10 W. Thermocouples attached to the warmer and to the cooler surfaces show temperatures of 322 and 300 K, respectively. Calculate the thermal conductivity of the material at the mean temperature in W/m K. Problem 1.4
3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
The heat transfer coefficient for a gas flowing over a thin float plate 3-m long and 0.3-m wide varies with distance from the leading edge according to hc(x)=10x1/4Wm2K If the plate temperature is 170C and the gas temperature is 30C, calculate (a) the average heat transfer coefficient, (b) the rate of heat transfer between the plate and the gas, and (c) the local heat flux 2 m from the leading edge. Problem 1.18
A square silicon chip 7mm7mm in size and 0.5-mm thick is mounted on a plastic substrate as shown in the sketch below. The top surface of the chip is cooled by a synthetic liquid flowing over it. Electronic circuits on the bottom of the chip generate heat at a rate of 5 W that must be transferred through the chip. Estimate the steady-state temperature difference between the front and back surfaces of the chip. The thermal conductivity of silicon is 150 W/m K. Problem 1.6
2.45 Heat is transferred from water to air through a brass wall . The addition of rectangular brass fins, 0.08 cm thick and 2.5 cm long, spaced 1.25 cm apart, is contemplated. Assuming a water-side heat transfer coefficient of and an airside heat transfer coefficient of , compare the gain in heat transfer rate achieved by adding fins to (a) the water side, (b) the air side, and (c) both sides. (Neglect temperature drop through the wall.)
2.42 A circumferential fin of rectangular cross section, 3.7-cm OD and 0.3 cm thick, surrounds a 2.5-cm- diameter tube as shown below. The fin is constructed of mild steel. Air blowing over the fin produces a heat transfer coefficient of K. If the temperatures of the base of the fin and the air are and , respectively, calculate the heat transfer rate from the fin.
Estimate the rate of heat loss per unit length from a 5-cm ID, 6-cm OD steel pipe covered with high-temperature insulation having a thermal conductivity of 0.11 W/(m K) and a thickness of 1.2 cm. Steam flows in the pipe. It has a quality of 99% and is at 150C. The unit thermal resistance at the inner wall is 0.0026(m2K)/W the heat transfer coefficient at the outer surface is 17W/(m2K) and the ambient temperature is 16C.
Steam at 120°C flows in a cast iron pipe (k = 80 W/m K) whose inner and outer diameters are Di = 5 cm and Do = 5.5 cm respectively. The pipe is covered with 3-cm-thick glass wool insulation with k = 0.05 W/m K. Assuming that the inside surface temperature of the pipe wall is at 120°C and the outer surface of insulation is at 28°C, calculate the heat loss (in watts) for 15 m of pipe.
an unsisulated 100 mm diameter steam pipe runs for 25 meters inside a room whose walls and air are at a temperature of 25 C. the superheated steam inside the pipe maintains the temperature at the pipe surface at 150 C. if the natural convection heat transfer coefficient of the air outside the pipe is 10 w/m^2 k and the surface emissivity is 0.8, compute for the convection thermal resistance of the air film surrounding the pipe in k/W
Hot engine oil is being transported in a horizontal pipe (k = 15 W/m∙K, Di = 5 cm) with a wall thickness of 5 mm. The pipe is covered with a 5-mm-thick layer of insulation (k = 0.15 W/m∙K). A length of 2 m of the outer surface is exposed to cool air at 10°C. If the pipe inner surface temperature is at 90°C, determine the outer surface temperature. Hint: The pipe outer surface temperature has to be found iteratively. Begin the calculations by using a film temperature of 50°C.
A steel tube with 6 cm ID, 8.2 cm OD and k=18 W/m-C is covered with an insulative covering of thickness 3 cm and k = 0.3 W/m-C . A hot gas at 330 C with h = 400 W/m^2-C flows inside the tube. The outer surface of the insulation is exposed to cooler air at 28 C with h = 60 W/m^2-C. Calculate the heat loss from the tube to the air for 12 m of the tube and the temperature drops resulting from the thermal resistances of the hot gas flow, the steel tube, the insulation layer and the outside air.
J 5 A cylindrical steel tank with a diameter of 1.8m and a height of 2m, is insulated with polyurethane on its lateral faces and its lid. The insulation is 40 mm thick and covered with a thin layer of metal. The tank contains water that is kept warm by an electric heater in such a way as to maintain the inner surface of the tank at a temperature of 55C. The ambient air temperature is 10C and the external skin coefficient is 10 w/m2K. If the energy cost is $0.15/kwh. What is the monthly energy cost for water storage?