3-202 A 0.2-cm-thick, 10-cm-high, and 15-cm-long circuit board houses electronic componernts on one side that dissipate a total of 15 W of heat uniformly. The board is impregnated with conductingmetal fillings and has an effective thermal conductivity of 12 W/m-K. All the heat generated in the components is conducted across the circuit board and is dissipated from the back side of the board to amedium at 37C, with a heat transfer coefficient of 45 W/m2-.K. (a) Determine the surface temperatures on the two sides of the circuit board. (b) Now a 0.1-cm-thick, 10-cm-high, and 15-cm-long aluminumplate (k 237 W/m-K) with 20 0.2-cm-thick, 2-cm-long, and 15-cm-wide aluminum fins of rectangular profile are attached to the back side of the circuit board with a 0.03-cm-thick epoxy adhesive (k = 1.8W/m K). Determine the new temperatures on the two sides of the circuit board.FIGURE P3-202ElectroniccomponentsFin15 cmL0.3 cm10 cm0.2 cm20 finsmm2 mm

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Asked Sep 25, 2019
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3-202 A 0.2-cm-thick, 10-cm-high, and 15-cm-long circuit board houses electronic componernts on one side that dissipate a total of 15 W of heat uniformly. The board is impregnated with conducting
metal fillings and has an effective thermal conductivity of 12 W/m-K. All the heat generated in the components is conducted across the circuit board and is dissipated from the back side of the board to a
medium at 37C, with a heat transfer coefficient of 45 W/m2-.K. (a) Determine the surface temperatures on the two sides of the circuit board. (b) Now a 0.1-cm-thick, 10-cm-high, and 15-cm-long aluminum
plate (k 237 W/m-K) with 20 0.2-cm-thick, 2-cm-long, and 15-cm-wide aluminum fins of rectangular profile are attached to the back side of the circuit board with a 0.03-cm-thick epoxy adhesive (k = 1.8
W/m K). Determine the new temperatures on the two sides of the circuit board.
FIGURE P3-202
Electronic
components
Fin
15 cm
L0.3 cm
10 cm
0.2 cm
20 fins
mm
2 mm
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3-202 A 0.2-cm-thick, 10-cm-high, and 15-cm-long circuit board houses electronic componernts on one side that dissipate a total of 15 W of heat uniformly. The board is impregnated with conducting metal fillings and has an effective thermal conductivity of 12 W/m-K. All the heat generated in the components is conducted across the circuit board and is dissipated from the back side of the board to a medium at 37C, with a heat transfer coefficient of 45 W/m2-.K. (a) Determine the surface temperatures on the two sides of the circuit board. (b) Now a 0.1-cm-thick, 10-cm-high, and 15-cm-long aluminum plate (k 237 W/m-K) with 20 0.2-cm-thick, 2-cm-long, and 15-cm-wide aluminum fins of rectangular profile are attached to the back side of the circuit board with a 0.03-cm-thick epoxy adhesive (k = 1.8 W/m K). Determine the new temperatures on the two sides of the circuit board. FIGURE P3-202 Electronic components Fin 15 cm L0.3 cm 10 cm 0.2 cm 20 fins mm 2 mm

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Expert Answer

Step 1

Determine the thermal resistance due to conduction in the board.

 

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L kA 0.002 m 12 W/m Kx 0.1 mx 0.15 m R, 0.011 C/W Determine the thermal resistance due to convection from the board to the surrounding medium 1 kA 1 45 W/m2. Kx 0.1 m x 0.15 m R. 1.481 °C/W

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Step 2

Determine the total thermal resistance.

 

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R RR =0.011 °C/W+1.481 °C/W =1.492 °C/W Determine the surface temperature of one side of the circuit board which is not in contact with the medium Т - т. T 37°C 1481 °C/W 15 W T 59.38°C

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Step 3

Determine the surface temperature of one side of the ci...

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Q-T-7 15 W-9.38°C-T 0.011 C/W = 59.215°C 2

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