Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470501979
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
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Chapter 1, Problem 1.81P
During its manufacture, plate glass at 600°C is cooledby passing air over its surface such that the convectionheat transfer coefficient is
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It is designed in such a way that the internal temperature of a commercial heat treatment furnace can reach up to 165 oC. All surfaces of the furnace consist of firebrick (10 cm), insulation material and sheet metal (3mm) from the inside out. Given that the outdoor temperature is 22 oC, the outer sheet will be allowed to go up to 35 oC, which is a temperature that will not be disturbed by hand contact. In this case, determine the insulation material thickness to be used. Insulation material thermal conductivity coefficient is 0.066 insulation W / m oC, 60 W / m oC for sheet metal and 115 W / m oC for firebrick. Indoor heat transfer coefficient will be accepted as 25 W / m2 oC and 12 W / m2 oC for outdoor environment.
a. What is the heat flux, q"1 [in W/m2], at the left-hand side of layer B? Express your answer as a negative number if the heat flux goes to the left, and as a positive number if the heat flux goes to the right.
b.What is the heat flux, q"2 ( in W/m2) at the right-hand side of layer B? Express your answer as a negative number if the heat flux goes to the left, and as a positive number if the heat flux goes to the right.
c. What is the temperature, T1, on the left-hand side of layer B, in Celsius?
d. What is the temperature, T2, on the right-hand side of layer B, in Celsius?
It is designed in such a way that the internal temperature of a commercial heat treatment furnace can reach up to 165 oC. All surfaces of the furnace consist of firebrick (10 cm), insulation material and sheet metal (3mm) from the inside out. Given that the outdoor temperature is 22 oC, the outer sheet will be allowed to go up to 35 oC, which is a temperature that will not disturb in contact with hands. In this case, determine the insulation material thickness to be used. The thermal conductivity coefficient of the insulation material is insulation 0.066 W / m oC, 60 W / m oC for sheet metal and 115 W / m oC for firebrick. Indoor heat transfer coefficient will be accepted as 25 W / m2 oC and 12 W / m2 oC for outdoor environment.
Chapter 1 Solutions
Fundamentals of Heat and Mass Transfer
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