During a performance test of an insulation wall, a 2 m long×3-m wide portion of the wall is placed in a wind tunnel. The wall is made of 1.2 cm thick siding, 20 cm thick brick, and 1 cm thick plaster layers. The test holds one side of the wall surface (the plaster surface) constant at 20°C as shown in the figure. During the test, air is flown parallel to the 2-m side of the wall over the other side (i.e., over the siding) of the wall. The air temperature is -15°C. The free-stream velocity of air is 5 m/s. Assume a film temperature of -10°C for air. Find out the rate of heat loss through the wall (i.e., from the rightmost surface in the figure to air on the left) during the test. Justify if the assumed value of film temperature is reasonable. The thermal conductivity of the siding, brick, and plaster are, respectively, 0.09 W/m-K, 0.7 W/m-K, and 0.82 W/m-K. Neglect radiation effects. 403 W Siding Plaster - 15 °C Cold air flow ↓ Wind- tunnel side Inside, kept at constant temp Brick 20 °C

During a performance test of an insulation wall, a 2 m long×3-m wide portion of the wall is placed in a wind tunnel. The wall is made of 1.2 cm thick siding, 20 cm thick brick, and 1 cm thick plaster layers. The test holds one side of the wall surface (the plaster surface) constant at 20°C as shown in the figure. During the test, air is flown parallel to the 2-m side of the wall over the other side (i.e., over the siding) of the wall. The air temperature is -15°C. The free-stream velocity of air is 5 m/s. Assume a film temperature of -10°C for air. Find out the rate of heat loss through the wall (i.e., from the rightmost surface in the figure to air on the left) during the test. Justify if the assumed value of film temperature is reasonable. The thermal conductivity of the siding, brick, and plaster are, respectively, 0.09 W/m-K, 0.7 W/m-K, and 0.82 W/m-K. Neglect radiation effects. 403 W Siding Plaster - 15 °C Cold air flow ↓ Wind- tunnel side Inside, kept at constant temp Brick 20 °C

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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