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Surface 1 is long heated plate running through a large room. This plate is 0.3 m...
The lower surface of a horizontal aluminum plate 5 in. by 7 in. is heated by an electric resistance heater that supplies 10 W. The upper surface is cooled by free convection and radiation. The convective transfer coefficient is 1.2 Btu/hr ft2 °F and the air temperature is 70 °F. Surrounding room surfaces are also at 70 °F. Find the surface temperature of the aluminum if it is a) clean and shiny with ε=0.05 b) painted with ε=0.9
The interior surface of an oven of internal dimensions 1mx1mx1m has an emissivity of 0.8, and is maintained at a uniform temperature of 500 K. The oven is placed in a very large room where the ambient temperature is 300K. On the front wall of the oven is a square opening of dimensions 100mmx 100mm. To reduce the heat loss through the opening, a thin metallic plate is used to cover the opening. The emissivity of the cover plate surface...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
A 5 m long x 1m wide horizontal plate is heated on top and insulated on the bottom. The plate is maintained at 200 C. The air and walls of the room are maintaine d at 25°C. Determine the heat transfer by nature convection and radiation heat transfer. Assume an emissivity of 0.8.
An aluminum alloy (2024) plate, heated to a uniform temperature of 227°C, is allowed to cool while vertically suspended in a room where the ambient air and surroundings are at 27°C. The plate is 0.3 m square with a thickness of 15 mm. a) calculate the rate of heat transfer from the plate to the surrounding air. b) Develop an expression for the time rate of change of the plate temperature, assuming the temperature to be uni form at any...
1 answer & continue > The upper surface of a 60-cm-thick solid plate (k = 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/mK. The thermal conductivity of water at the film temperature of T; = (1,1770) =(60°C + 20°C)/2 = 40°C is kfluid =...
HELP MEEE An uninsulated steam pipe passes through a room where the temperatures of the air and its walls are 38 degrees. The outer diameter of the pipe is 90 mm, the temperature and spreading rate of its surface are 200 degrees and 0.8, respectively. Calculate the radiating power of the surface and the radiation to the surface. Since the heat transfer coefficient with natural convection from the surface to the air is 25 w/m^2.K, what is the heat loss...
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/ mK. (T..+) The thermal conductivity of water at the film temperature of T, = =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/mK. 1. value...
The interior surface of an oven of internal dimensions 1mx1mx1m has an is maintained at a uniform temperature of 500 K. The oven is placed in a very large room the ambient temperature is 300K. On the front wall of the oven is a square opening of dimensions ce of an o where 00mm. To reduce the heat loss through the opening, a thin metallic plate is used to cover the opening. The emissivity of the cover plate surface facing...
A 3 m high room with a 4 m x 4 m floor area is heated using electrical resistance heaters placed on the ceiling. The ceiling is maintained at 35oC and can be treated as a black body. The floor is at 15°C and has an emissivity of 0.8. The side walls of the room are well insulated. Neglecting heat transfer by convection, find the rate of heat loss from the room through the floor Ceiling: 1 4 m x...