Heat Transfer Log mean temperature difference (LMTD) cannot be used, if heat transfer co-efficient over the entire heat exchanger is not constant none of the listed here the heat capacity is not constant and there is a phase change. there exists an unsteady state heat transfer co-efficient over the entire heat exchanger is not constant none of the listed here the heat capacity is not constant and there is a phase change. there exists an unsteady state ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) Independent of 't' ∝ √t ∝ t ∝ 1/t Independent of 't' ∝ √t ∝ t ∝ 1/t ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions ? Assume that the conductive heat transfer co-efficient is infinitely large. 20 minutes 5 minutes 40 minutes 10 minutes 20 minutes 5 minutes 40 minutes 10 minutes ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by Painting the surface white (with aluminium paint) Giving the surface a mirror finish Roughening the surface Painting the surface black Painting the surface white (with aluminium paint) Giving the surface a mirror finish Roughening the surface Painting the surface black ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger. Twice Thrice Four times Once Twice Thrice Four times Once ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer __________ heat exchanger is the most suitable, when the temperature of shell side fluid is much higher than that of tube side. U-tube Three pass, fixed tube sheet Single pass, fixed tube sheet None of these U-tube Three pass, fixed tube sheet Single pass, fixed tube sheet None of these ANSWER DOWNLOAD EXAMIANS APP
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