Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Chapter 2.8, Problem 98P
For heat transfer purposes, a standing man can be modeled as a 30-cm-diameter, 175-cm-long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34°C. For a convection heat transfer coefficient of 10 W/m2·°C, determine the rate of heat loss from this man by convection in an environment at 20°C.
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Heat transfer
Consider a person standing in a breezy room at 20°C. Determine the total rate of heat transfer from this person if the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29°C, respectively, and the convection heat transfer coefficient is 6 W/m2 ·°C (Fig. 2–75).
Q:A hot surface at 100°C is to be cooled by attach-
ing 3-cm-long, 0.25-cm-diameter aluminum pin fins (k
237 W/m · °C) to it, with a center-to-center distançe of 0.6 cm.
The temperature of the surrounding medium is 30°C, and the
heat transfer coefficient on the surfaces is 35 W/m2 . °C.
Determine the rate of heat transfer from the surface for a
1-m X 1-m section of the plate. Also determine the overall
effectiveners of the fins. Ans. Q=17.4 kW , E fin = 7.1
3 cm
0.6
cm
L0.25
cm
Chapter 2 Solutions
Thermodynamics: An Engineering Approach
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