A circuit board with a dense distribution of integrated circuits (ICs) and dimensions of \(20 \mathrm{~mm} \times 20 \mathrm{~mm}\) on a side is cooled by the parallel flow of atmospheric air with a velocity of \(2 \mathrm{~m} / \mathrm{s}\).

From wind tunnel tests under the same flow conditions, the average frictional shear stress on the upper surface is determined to be \(0.0575 \mathrm{~N} / \mathrm{m}^{2}\). What is the allowable power dissipation from the upper surface of the board if the average surface temperature of the ICs must not exceed the ambient air temperature by more than \(30^{\circ} \mathrm{C}\) ? Evaluate the thermophysical properties of air at \(300 \mathrm{~K}\).

Transcribed Image Text:

Air u = 2 m/s Integrated circuit (IC) Circuit board