An industrial spherical oven has 2.8 m diameter. It is placed in a factory floor where the air temperature is 25°C and surrounding temperature is 30°C. When the oven is running under part-load condition the temperature of the outer surface of the oven is 60°C and under peak load conditions the surface temperature reaches to 250°C. The total heat loss from the oven under peak-load conditions was found to be 905 kW. The emissivity of the oven surface is 0.75. Find the convection coefficient of air around the oven in this condition. 150.76 W/m2K

An industrial spherical oven has 2.8 m diameter. It is placed in a factory floor where the air temperature is 25°C and surrounding temperature is 30°C. When the oven is running under part-load condition the temperature of the outer surface of the oven is 60°C and under peak load conditions the surface temperature reaches to 250°C. The total heat loss from the oven under peak-load conditions was found to be 905 kW. The emissivity of the oven surface is 0.75. Find the convection coefficient of air around the oven in this condition. 150.76 W/m2K

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A group of 25 power transistors, dissipating 1.5 W each, are to be cooled by attaching them to a black-anodized square aluminum plate and mounting the plate on the wall of a room at 30°C. The emissivity of the transistor and the plate surfaces is 0.9. Assuming the heat transfer from the back side of the plate to be negligible and the temperature of the surrounding surfaces to be the same as the air temperature of the room, determine the size of the plate if the average surface temperature of the plate is not to exceed 50°C.
A certain 1m body at 20 C is display on a top of a building during the night. the body sees nothing but the sky which has an effective temperaure of 110 k. determine the heat transfer rate from the body to the sky if the body temperature is maintained at 23 C. the surface emissivity of the body is equal to 0.90
An average person generates heat at a rate of 240 Btu/h while resting in a room at 70°F. Assuming onequarter of this heat is lost from the head and taking the emissivity of the skin to be 0.9, determine the average surface temperature of the head when it is not covered. The head can be approximated as a 12-in-diameter sphere, and the interior surfaces of the room can be assumed to be at the room temperature.
An electronic box that consumes 200 W of power is cooled by a fan blowing air into the box enclosure. The dimensions of the electronic box are 15 cm * 50 cm * 50 cm, and all surfaces of the box are exposed to the ambient except the base surface. Temperature measurements indicate that the box is at an average temperature of 32°C when the ambient temperature and the temperature of the surrounding walls are 25°C. If the emissivity of the outer surface of the box is 0.75, determine the fraction of the heat lost from the outer surfaces of the electronic box.
Question 4:Consider a person standing in a room maintained at20°C at all times. The inner surfaces of the walls, floors, andceiling of the house are observed to be at an average temperature of 12°C in winter and 23°C in summer. Determine therates of radiation heat transfer between this person and the surroundingsurfaces in both summer and winter if the exposedsurface area, emissivity, and the average outer surface temperatureof the person are 1.6 m2, 0.95, and 32°C, respectively.
02. An electronic box that consumes 180 W of power is cooled by a fan blowing air into the box enclosure. The dimensions of the electronic box are 15 cm x 50 cm x 50 cm, and all surfaces of the box are exposed to the ambient except the base surface. Temperature measurements indicate that the box is at an average temperature of 32°C when the ambient temperature and the temperature of the surrounding walls are 25°C. The emissivity of the outer surface is 0.85. Determine: (a) The heat lost from the top surface, (b) The heat lost from the side surfaces, (c) The total heat lost by radiation and (d) the total fraction of the heat lost from the outer surfaces of the electronic box.
Required information Consider an aluminum pan used to cook stew on top of an electric range. The bottom section of the pan is 0.25 cm thick and has a diameter of 14 cm. The electric heating unit on the range top consumes 900 W of power during cooking, and 90 percent of the heat generated in the heating element is transferred to the pan. During steady operation, the temperature of the nner surface of the pan is measured to be 108°C. Determine the heat flux at the bottom of the pan (up to 1 decimal place). The heat flux at the bottom of the pan = |kW/m2 %3D 27 ^ D a ENG 11/1C 18°C Clear
a certain body at 20 C is display on a top of a building during the night. the body sees nothing but the sky which has effective temperature of 110 k. determine the heat transfer rate from the body to the sky if the body temperature is maintained at 23 C. the surface to the sky emissivity of the body is equal to 0.92
A 1000-W iron is left on the iron board with its base exposed to the air at 20°C. The convection heat transfer coefficient between the base surface and the surrounding air is 35 W/m2. C. If the base has an emissivity of 0.6 and a surface area of 0.02 m2, determine the temperature of the base of the iron.
A 1.2 m wide and 5.1 m long solar collector is mounted to a roof. Now the average surface temperature of the solar collector is measured to be 50 oC. The effective surrounding sky temperature is 8 oC. If the emissivity of the collector is 0.88, determine the rate of heat transfer from the collector to the surroundings due to radiation.
Consider a thin 16-cm-long and 20-cm-wide horizontal plate suspended in air at 20°C. The plate is equipped with electric resistance heating elements with a rating of 20 W. Now the heater is turned on and the plate temperature rises. Determine the temperature of the plate when steady operating conditions are reached. The plate has an emissivity of 0.90 and the surrounding surfaces are at 17°C. As an initial guess, assume a surface temperature of 50°C. Is this a good assumption?
Consider a cylindrical tank with a surface temperature of 44°C which contains water. The height of the tank is 1.1 m and its diameter is 0.4 m. The tank is in a room at 20°C. If the surrounding temperature is also at 20°C, calculate the total rate of heat transfer from all surfaces of the tank by natural convection and radiation. Consider the emissivity to be 0.4. Assumptions: 1 Steady operating conditions exist. 2 Air is an ideal gas. 3 The local atmospheric pressure is 1 atm. Note. Report your solution step by step and clearly.