3-5 The wall of a drying oven is constructed of an insulation layer of glass-wool (k=0.05 W/m.K) sandwiches between thin metal sheets of negligible thermal resistances. The oven is at Tøl = 300 °C, and the corresponding convection coefficient is h=25 W/(m?.°C). The inner wall surface absorbs a radiant heat flux of q=250 W/m² from a hotter objects placed inside the oven. The outside surface of the wall rejects heat by convection into an ambient air at room air is at T2 =25 °C, with a convection coefficient of h2 =15 W/(m².°C). a- Draw the thermal circuit for the wall and label the temperatures, heat rates, and thcrmal resistances. b- Determine the insulation thickness required to maintain the outer surface at a safe-to-touch temperature of 45 °C. Absorbed Insulation radiation 2A Oven air Ambient air 111

3-5 The wall of a drying oven is constructed of an insulation layer of glass-wool (k=0.05 W/m.K) sandwiches between thin metal sheets of negligible thermal resistances. The oven is at Tøl = 300 °C, and the corresponding convection coefficient is h=25 W/(m?.°C). The inner wall surface absorbs a radiant heat flux of q=250 W/m² from a hotter objects placed inside the oven. The outside surface of the wall rejects heat by convection into an ambient air at room air is at T2 =25 °C, with a convection coefficient of h2 =15 W/(m².°C). a- Draw the thermal circuit for the wall and label the temperatures, heat rates, and thcrmal resistances. b- Determine the insulation thickness required to maintain the outer surface at a safe-to-touch temperature of 45 °C. Absorbed Insulation radiation 2A Oven air Ambient air 111

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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