The heat transfer coefficient for air flowing over a sphere is to be determined by observing the temperature-time history of a sphere fabricated from pure copper. The sphere, which is 12.7 mm in diameter, is at 66°C before it is inserted into an airstream having a temperature of 27°C. A thermocouple on the outer surface of the sphere indicates 55°C 69 s after the sphere is inserted into the airstream. Assume and then justify that the sphere behaves as a spacewise isothermal object and calculate the heat transfer coefficient.

The heat transfer coefficient for air flowing over a sphere is to be determined by observing the temperature-time history of a sphere fabricated from pure copper. The sphere, which is 12.7 mm in diameter, is at 66°C before it is inserted into an airstream having a temperature of 27°C. A thermocouple on the outer surface of the sphere indicates 55°C 69 s after the sphere is inserted into the airstream. Assume and then justify that the sphere behaves as a spacewise isothermal object and calculate the heat transfer coefficient.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Question

Heat transand P
5.8 The heat transfer coefficient for air flowing over a sphere
is to be determined by observing the temperature-time
history of a sphere fabricated from pure copper. The
sphere, which is 12.7 mm in diameter, is at 66°C before it
is inserted into an airstream having a temperature of
27°C. A thermocouple on the outer surface of the sphere
indicates 55°C 69 s after the sphere is inserted into the
airstream. Assume and then justify that the sphere
behaves as a spacewise isothermal object and calculate
the heat transfer coefficient.
T 2706

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