A container, spherical in shape, with an outside diameter of 30 cm holds a hot fluid at 180°C. The container is insulated with two layers of each 10 cm thick of insulation of k = 0.05 and k2 = 0.20 W/mK (starting from inside). If the interface temperature between the first and second layer of insulation is 50°C, what is the rate of heat transfer through the container in Watts? Also, determine the outside surface temperature of the second layer of insulation.

A container, spherical in shape, with an outside diameter of 30 cm holds a hot fluid at 180°C. The container is insulated with two layers of each 10 cm thick of insulation of k = 0.05 and k2 = 0.20 W/mK (starting from inside). If the interface temperature between the first and second layer of insulation is 50°C, what is the rate of heat transfer through the container in Watts? Also, determine the outside surface temperature of the second layer of insulation.

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.19P: 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the...

See similar textbooks

Similar questions

1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
1.29 A spherical interplanetary probe with a 30-cm diameter contains electronic equipment that dissipates 100 W. If the probe surface has an emissivity of 0.8, what is its surface temperature in outer space? State your assumptions in the calculations.
2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.
1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a well-insulated 40-L tank of water that is initially at 300 K. If each heater dissipates 500 W, what is the time required for bringing the water temperature in the tank to 340 K? State your assumption for your analysis.
Question 4 The window of a room is made of 5 mm thick glass which has a thermal conductivity of 1.4 W/m-K. A heater is used to maintain the room temperature at 22 °C. Take the convection heat transfer coefficients on the outer surface of the window to be 12 W/m²-K. Take appropriate assumptions while solving this problem. (a) T₁=15°C TA -A- 1m x 3m = 3m², k=1.4W/m-K -T₂=5°C L=0.005m Figure Q2 Determine the heater thermal load to maintain the room temperature?
Question 4 The window of a room is made of 5 mm thick glass which has a thermal conductivity of 1.4 W/m-K. A heater is used to maintain the room temperature at 22 °C. Take the convection heat transfer coefficients on the outer surface of the window to be 12 W/m²-K. Take appropriate assumptions while solving this problem. (a) T₁-15°C TA -A=1m x 3m 3m², k=1.4 W/m-K I L=0.005m Figure Q2 ** -T₂=5°C Find the convection heat transfer coefficients on the inner surface of the window.
Two large steel plates at temperature of 90°C and 70°C are separated by a steel rod 2.5 cm diameter and 0.25 m long. The rod is welded to each plate. The space between the plates is filled with insulation which also insulates the circumference of the rod. Because of voltage difference between the two plates current flows through the rod and the electrical energy is dissipated at a rate of 10 W. Determine the maximum temperature in the rod and the heat flux at each end. Proceed to compare the net heat flow rate of the two ends with the total rate of heat generation. Thermal conductivity for the rod material is 42.5 W/m-deg.
The wall of a furnace consists of 200 mm thick refractory brick (k = 3 Btu / hr-ft2-0F), 100 mm thick bricks (k = 0.050 Btu / hr-ft2-0F) and 6 mm thick steel. The temperature on the side of the refractory brick layer of the furnace is 1150 C, and the temperature on the outer steel surface is 30C. There is a heat loss of 300 W / square meter at the wall of the furnace. It is difficult to prevent the thin air additions between the brick layers and the brick layer and the steel wall. How many mm of brick layers is the total thickness of these air layers equivalent?
Two identical aluminum plates with thickness of 30 cm are pressed against each other at an average pressure of 1 atm. The interface, sandwiched between the two plates, is filled with glycerin. On the left outer surface, it is subjected to a uniform heat flux of 7800 W/m2 at a constant temperature of 50°C. On the right outer surface, the temperature is maintained constant at 30°C. Determine the thermal contact conductance of the glycerin at the interface, if the thermal conductivity of the aluminum plates is 237 W/m∙K. Discuss whether the value of the thermal contact conductance is reasonable or not
In a coal-fired power plant, a furnace wall consists of a 125-mm-wide refractory brick and a 125-mm-wide insulating firebrick separated by an air gap. The outside wall is covered with a 12 mm thickness of plaster. The inner surface of the wall is at 1100◦C, and the room temperature is 25◦C. The heat-transfer coefficient from the outside wall surface to the air in the room is 17 W/m2 K, and the resistance to heat flow of the airgap is 0.16 K/W. The thermal conductivities of the refractor brick, the insulating firebrick, and the plaster are 1.6, 0.3, and 0.14 W/m K, respectively. Calculate the rate of heat loss per unit area of wall surface
i need the answer quickly
Heat Loss by Convection and Conduction.A glass window with an area of 0.557 m2is installed in the wooden outside wall of a room. The wall dimensions are 2.44 × 3.05 m. The wood has akof 0.1505 W/m · K and is 25.4 mm thick. The glass is 3.18 mm thick and has akof 0.692. The inside room temperature is 299.9 K (26.7°C) and the outside air temperature is 266.5 K. The convection coefficienthion the inside wall of the glass and the wood is estimated as 8.5 W/m2· K; the outsideh0is also estimated as 8.5 for both surfaces. Calculate the heat loss through the wooden wall, through the glass, and the total.