HEAT+MASS TRANSFER:FUND.+APPL.
HEAT+MASS TRANSFER:FUND.+APPL.
6th Edition
ISBN: 9780073398198
Author: CENGEL
Publisher: RENT MCG
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Chapter 1, Problem 159P

A person’s head can be approximated as a 25-cm-diameter sphere at 35 o C with an emissivity of 0.95. Heat is lost form the head to the surrounding air at 25 o C by convection with a heat transfer coefficient of 11 W/m2. K and by radiation to the surrounding surfaces at 10 o C .

Disregarding the neck, determine the total rate of heat loss from the head.

  1. 22   W
  2. 27   W
  3. 49  W
  4. 172  W
  5. 249   W

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Required information Consider a person whose exposed surface area is 21 m4, emissivity is 0.5, and surface temperature is 32°C. Given: 0 = 5.67×10-8 W/m2.K4 Determine the rate of heat loss from that person by radiation in a large room having walls at a temperature of 300 K (upto 3 decimal places). You must provide an answer before moving to the next part. The rate of heat loss from the person at 300K is W.

Chapter 1 Solutions

HEAT+MASS TRANSFER:FUND.+APPL.

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