When a flat plate which is below the saturation temperature of vapour (vapour which used to flow over the plate). when the vapour used to flow on the plate there is
an layer formed which is in thin form with smooth surface called liquid film this is occured by the condensation. this condensation is called film condensation.
This sprocess is less efficient in heat transfer than drop wise due to the formation of liquid layer on it. this resist the heat transfer rate.
In this process the fluid flows on the surface leads to wet the surface of the plate.
This condensate is free from impurites and there is constant fluid properties.
By the help of gravity the film used to flow.
Drop Wise Condensation:
This process used to transfer the more heat transfer rate due to the contact surface of condensate does not form any layers on it, there is only liquid droplets occur on it, this helps to more contact with the surface and helps to transfer the high amount of heat.
This can be improved by using coatings on surface and by using of non-wetting chemical give high results.
