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 1.77P
An experiment to determine the convection coefficientassociated with airflow over the surface of a thickstainless steel casting involves the insertion of thermocouples into the casting at distances of 10 and 20 mm from the surface along a hypothetical line normal to thesurface. The steel has a thermal conductivity of
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Air at 25 ° C blows over the hot steel plate whose surface temperature is maintained at 150 ° C. The plates are 50 cm x 40 cm in dimensions and 2.5 cm thick. The convection heat transfer coefficient on the upper surface is 40 W / (m² ° C). The thermal conductivity of steel is 45 W / (m ° C). Calculate the hourly heat loss from the plate surface. a. heat loss per hour = Answer kJ. b. If the reverse side surface temperature is maintained, determine the hourly heat loss occurring = Answer kJ. Air at 25 ° C blows over the hot steel plate whose surface temperature is maintained at 150 ° C. The plates are 50 cm x 40 cm in dimensions and 2.5 cm thick. The convection heat transfer coefficient on the upper surface is 40 W / (m² ° C). The thermal conductivity of steel is 45 W / (m ° C). Calculate the hourly heat loss from the plate surface. a. heat loss per hour = Answer kJ. b. If the reverse side surface temperature is maintained, determine the hourly heat loss occurring = Answer kJ.
During a cold winter day, wind at 55 km/h is blowing parallel to a 4m high and 10m long wall of a house. If the air outside is at 5 degrees Celsius and the surface temperature of the wall is 12 degrees Celsius , determine the rate of heat loss from the wall by convection. What would your answer be if the wind velocity has doubled?
From Table A-1:thermal conductivity, k = 0.0246 W/m degrees Celsiusviscosity, v = 1.4 x 10^-5 m^2/sPrandtl no. Pr = 0.717
Air at 25 ° C blows over the hot steel plate whose surface temperature is maintained at 150 ° C. The plates are 50 cm x 40 cm in dimensions and 2.5 cm thick. The convection heat transfer coefficient on the upper surface is 20 W / (m² ° C). The thermal conductivity of steel is 45 W / (m ° C). Calculate the hourly heat loss from the plate surface.
a. heat loss per hour = Answer
kJ.
b. If the reverse side surface temperature is maintained, determine the hourly heat loss occurring = Answer
kJ.
Chapter 1 Solutions
Fundamentals of Heat and Mass Transfer
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