A vertical square plane plate of an electronic device, 100 mm on a side, dissipates heat....

  

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A vertical square plane plate of an electronic device, 100 mm on a side, dissipates heat. The back surface is well insulated and the front surface is exposed to quiescent (still/stagnant) air at 25 °C and 1 atm. Assuming there is only natural convection and a uniform surface temperature as 275 °C, drawing schematic view of the problem find the total heat transfer rate from the plate to the air, q (W). Following definitions are valid for the natural convection heat transfer coefficient for a vertical plane plate or plane wall. Nu, = 0.68+ 0.670 Ra 9/16 74/9 for Ra, ≤1-10° (for laminar natural convection!) 0.492 1+ Pr Nu₁ = 0.387 Ra 1/6 =0.825+ 9/16 78/27 0.492 for Ra, >1.10° (for turbulent natural convection!) 1+ Pr Table: Thermophysical properties of air at atmospheric pressure. A vertical square plane plate of an electronic device, 100 mm on a side, dissipates heat. The back surface is well insulated and the front surface is exposed to quiescent (still/stagnant) air at 25 °C and 1 atm. Assuming there is only natural convection and a uniform surface temperature as 275 °C, drawing schematic view of the problem find the total heat transfer rate from the plate to the air, q (W). Following definitions are valid for the natural convection heat transfer coefficient for a vertical plane plate or plane wall. Nu, = 0.68+ 0.670 Ra 9/16 74/9 for Ra, ≤1-10° (for laminar natural convection!) 0.492 1+ Pr Nu₁ = 0.387 Ra 1/6 =0.825+ 9/16 78/27 0.492 for Ra, >1.10° (for turbulent natural convection!) 1+ Pr Table: Thermophysical properties of air at atmospheric pressure.