For free convection from / to horizontal plate, characteristic length=L= area/ perimeter, Properties ( (B, v,...

  

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For free convection from / to horizontal plate, characteristic length=L= area/ perimeter, Properties ( (B, v, Pr ,k.etc) are calculated at TR %3! To+ Ts for gases B = - K-1 !! 2 TR hL Nu 0.54 Ra0.25. gB(T,-T.)L3 v2 Cpl Ra = Gr Pr, Gr Pr= k 2- An electronic component can be modeled as a plane wall, one side is subjected to combustion environment at 500°C; while the other side is cooled and maintained at 100°C. The wall material has thermal conductivity k = 4 W/m K. The gas side convection heat transfer coefficient is 250 W/m K. Thermal limitations imposed that temperature of the wall must not exceed 450°C. What is the maximum wall thickness? For free convection from / to horizontal plate, characteristic length=L= area/ perimeter, Properties ( (B, v, Pr ,k.etc) are calculated at TR %3! To+ Ts for gases B = - K-1 !! 2 TR hL Nu 0.54 Ra0.25. gB(T,-T.)L3 v2 Cpl Ra = Gr Pr, Gr Pr= k 2- An electronic component can be modeled as a plane wall, one side is subjected to combustion environment at 500°C; while the other side is cooled and maintained at 100°C. The wall material has thermal conductivity k = 4 W/m K. The gas side convection heat transfer coefficient is 250 W/m K. Thermal limitations imposed that temperature of the wall must not exceed 450°C. What is the maximum wall thickness?