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The condensate film runs down a vertical flat surface where saturated steam is allowed to condense. Condensation’s local coefficient of heat transfer

The condensate film runs down a vertical flat surface where saturated steam is allowed to condense. Condensation’s local coefficient of heat transfer Correct Answer Decreases with increasing distance from the top of the surface

It decreases with increasing thickness of condensate film.

Related Questions

Saturated steam is allowed to condense over a vertical flat surface and the condensate film flows down the surface. The local coefficient of heat transfer for condensation
In a surface condenser, the water flowing through a series of tubes at the rate of 200 kg/hr is heated from 15 degree Celsius to 75 degree Celsius. The steam condenses on the outside surface of tubes at atmospheric pressure and the overall heat transfer coefficient is estimated at 860 k J/m2 hr degree. Find the number of transfer units of the heat exchanger. At the condensing pressure, stream has saturation temperature 0f 100 degree Celsius and the latent heat of vaporization is 2160 k J/kg. Further, the steam is initially just saturated and the condensate leaves the exchanger without sub-cooling i.e. only latent heat of condensing steam is transferred to water. Take specific heat of water as 4 k J/kg K
In a surface condenser, the water flowing through a series of tubes at the rate of 200 kg/hr is heated from 15 degree Celsius to 75 degree Celsius. The steam condenses on the outside surface of tubes at atmospheric pressure and the overall heat transfer coefficient is estimated at 860 k J/m2 hr degree. Find the effectiveness of the heat exchanger. At the condensing pressure, stream has a saturation temperature 0f 100 degree Celsius and the latent heat of vaporization is 2160 k J/kg. Further, the steam is initially just saturated and the condensate leaves the exchanger without sub-cooling i.e. only latent heat of condensing steam is transferred to the water. Take specific heat of water as 4 k J/kg K
Which are the correct statements? (a) Film condensation usually occur on oily surface. (b) Temperature of condensate gradually increases towards the liquid-vapour interface. (c) Suitable coating is used to promote dropwise condensation. (d) Dropwise condensation gives lower heat transfer rate than film condensation.
A two pass surface condenser is required to handle the exhaust from a turbine developing 15 MW with specific steam consumption of 5 kg/k W h. The quality of exhaust steam is 0.9, the condenser vacuum is 66 cm of mercury while the bar meter reads 76 cm of mercury. The condenser tubes are 28 mm inside diameter, 4 mm thick and water flows through tubes with a speed of 3 m/s and inlet temperature 20 degree Celsius. All the steam is condensed, the condensate is saturated water and temperature of cooling water at exit is 5 degree Celsius less than the condensate temperature. Assuming that overall coefficient of heat transfer is 4 k W/m2 degree, determine the mass of cooling water circulated
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Statement 1: Film-type condensation has a higher heat transfer co-efficient than drop-wise condensation. Statement 2: Drop-wise condensation is easier to maintain than Film-type condensation
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The average heat transfer co-efficient for laminar film condensation on vertical surface is inversely proportional to (where, ΔT = Temperature drop across condensate film )