7-128 To defrost ice accumulated on the outer surface of an automobile windshield, warm air is blown over the inner surface of the windshield. Consider an automobile windshield (k = 1.4 W/m.K) with an overall height of 0.5 m and thick- ness of 5 mm. The outside air (1 atm) ambient temperature is -20°C, and the average airflow velocity over the outer windshield surface is 80 km/h, while the ambient temperature inside the automobile is 25°C. Determine the value of the con- vection heat transfer coefficient for the warm air blowing over the inner surface of the windshield that is needed to cause the accumulated ice to begin melting. Assume the windshield sur- face can be treated as a flat plate surface.

7-128 To defrost ice accumulated on the outer surface of an automobile windshield, warm air is blown over the inner surface of the windshield. Consider an automobile windshield (k = 1.4 W/m.K) with an overall height of 0.5 m and thick- ness of 5 mm. The outside air (1 atm) ambient temperature is -20°C, and the average airflow velocity over the outer windshield surface is 80 km/h, while the ambient temperature inside the automobile is 25°C. Determine the value of the con- vection heat transfer coefficient for the warm air blowing over the inner surface of the windshield that is needed to cause the accumulated ice to begin melting. Assume the windshield sur- face can be treated as a flat plate surface.

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

7-128 To defrost ice accumulated on the outer surface of
an automobile windshield, warm air is blown over the inner
surface of the windshield. Consider an automobile windshield
(k = 1.4 W/m.K) with an overall height of 0.5 m and thick-
ness of 5 mm. The outside air (1 atm) ambient temperature
is -20°C, and the average airflow velocity over the outer
windshield surface is 80 km/h, while the ambient temperature
inside the automobile is 25°C. Determine the value of the con-
vection heat transfer coefficient for the warm air blowing over
the inner surface of the windshield that is needed to cause the
accumulated ice to begin melting. Assume the windshield sur-
face can be treated as a flat plate surface.

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