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A circular disk of diameter 0.05 m supports a thin film of water. When 0.95 W of electric power is supplied, the water reaches a steady-state temperature of 305 K and water evaporates at the rate of 5 x 10-3 kg/h into the surrounding dry air, which is at a temperature of 295 K. (a) Calculate the heat transfer coefficient for transfer of heat by convection from the water to the air. (b) If the relative humidity of the air is increased to 50% at 295 K and the power input is maintained at 0.95 W, does the water temperature increase or decrease? (c) Does the rate of evaporation increase or decrease? (d) Does the mass transport-heat transport analogy hold? A circular disk of diameter 0.05 m supports a thin film of water. When 0.95 W of electric power is supplied, the water reaches a steady-state temperature of 305 K and water evaporates at the rate of 5 x 10-3 kg/h into the surrounding dry air, which is at a temperature of 295 K. (a) Calculate the heat transfer coefficient for transfer of heat by convection from the water to the air. (b) If the relative humidity of the air is increased to 50% at 295 K and the power input is maintained at 0.95 W, does the water temperature increase or decrease? (c) Does the rate of evaporation increase or decrease? (d) Does the mass transport-heat transport analogy hold?

Answer rating: 100% (QA)

A Given Disc dia D 005m Power P 095 W evaporation rate m 5 x 10 3 kghr 138 x 106 kgs since the elect... View the full answer