A 15-cm * 15-cm circuit board dissipating 20 W of power uniformly is cooled by air, which approaches the circuit board at 20°C with a velocity of 6 m/s. Disregarding any heat transfer from the back surface of the board, determine the surface temperature of the electronic components (a) at the leading edge and (b) at the end of the board. Assume the flow to be turbulent since the electronic components are expected to act as turbulators. For air properties evaluations assume a film temperature of 35°C. Is this a good assumption?
Energy transfer
The flow of energy from one region to another region is referred to as energy transfer. Since energy is quantitative; it must be transferred to a body or a material to work or to heat the system.
Molar Specific Heat
Heat capacity is the amount of heat energy absorbed or released by a chemical substance per the change in temperature of that substance. The change in heat is also called enthalpy. The SI unit of heat capacity is Joules per Kelvin, which is (J K-1)
Thermal Properties of Matter
Thermal energy is described as one of the form of heat energy which flows from one body of higher temperature to the other with the lower temperature when these two bodies are placed in contact to each other. Heat is described as the form of energy which is transferred between the two systems or in between the systems and their surrounding by the virtue of difference in temperature. Calorimetry is that branch of science which helps in measuring the changes which are taking place in the heat energy of a given body.
A 15-cm * 15-cm circuit board dissipating 20 W of
power uniformly is cooled by air, which approaches the circuit
board at 20°C with a velocity of 6 m/s. Disregarding any
surface temperature of the electronic components (a) at the
leading edge and (b) at the end of the board. Assume the flow
to be turbulent since the electronic components are expected
to act as turbulators. For air properties evaluations assume a
film temperature of 35°C. Is this a good assumption?
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