Question

A cylinder, 12 cm high and 8 cm in diameter, k = 12.5 W/mK, maintained at 36 ºC, is to be placed horizontally inside an environment filled with air at 1 atm and 4 ºC. What is the convection heat transfer rate between the cylinder and the air? (Note: assume the cylinder is surrounded by air at 4 ºC, and neglect heat transfer through the left and right end surfaces.)

A cylinder, 12 cm high and 8 cm in diameter, k = 12.5 W/mK, maintained at 36 °C, is to be placed horizontally inside an envir

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Answer #1

C Ts=36°c D - 8 cm. Ta=4°¢ le 12 cm The proportion of air at film Temperature Tg = Tst Td = 36+4 = 20e are : p=1,204 kg/m² KiRayleigh number (Rap) Rap = GB Le (TS-Tw) por 12 Ra 9.81x zaboş x 6.03% (36-4) * 6:715 (1-511 x1005) . Rą = 1.717x10C in corr4.234 1 NU=20.6 t 1. 203s NU= 16.97 Then nu ho 7 h = texno h = 0.0255 * 16.97 h = 5.409 W/m²K surface area (As) = ADDL = ñ x

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