Condensation horizontal rotating plate

Laminar film condensation on a rotating horizontal circular plate. 

Control volume used in the analysis of laminar film condensation on a rotating horizontal circular plate. 

A number of vertical flat disks, one of which is shown, are secured to a horizontal rotating shaft. The bottom half of the disk is immersed in a reservoir of heated feed water the top half passes between fixed condenser plates. 

The rate of condensation on a vertical surface is controlled by the force of gravity acting on the condensed liquid film. A consideration of Eq. (11.20) shows for example that for a vertical plate the mean heat transfer rate from the plate with laminar flow in the film is proportional to gw. Attempts have therefore been made to increase condensation rates by using centrifugal forces instead of the gravitational force to drain the condensed liquid film from the cold surface [55], The simplest example of this would be condensation on the upper surface of a cooled circular plate rotating in a horizontal plane. This situation is shown in Fig. 11.23. A Nusselt-type analysis of this situation will be considered in the present section. 

Steam at a saturation temperature of 50°C condenses on the upper surface of a rotating circular horizontal plate which has a diameter of 30 cm and which is kept at a surface temperature of 46°C. Plot the variation condensation rate with rotational speed for values between 50 and 1000 revolutions per minute. 

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