Fundamentals of Heat and Mass Transfer
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 7, Problem 7.50P

Consider the conditions of Problem 7.49, but now allow for radiation exchange between the surface of the heating element ( ε = 0.8 ) and the walls of the duct, which form a large enclosure at 27°C.

  1. Evaluate the steady-state surface temperature.
  2. If the heater is activated from an initial temperature of 27°C, estimate the time required for the surface temperature to come within 10°C of the steady-state value.
  3. To guard against overheating due to unanticipated excursions in the blower output, the heater controller is designed to maintain a fixed surface temperature of 275°C. Determine the power dissipation required to maintain this temperature for air velocities in the range 5 V 10 m/s .

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Chapter 7 Solutions

Fundamentals of Heat and Mass Transfer

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