FILM AND DROPWISE CONDENSATION EPUB!
In film wise condensation, the surface over which the steam condenses is wet-able and hence, as the steam condenses, a film of condensate is formed. face, dropwise condensation is much more effective then filmwise condensation condensation a laminar film of vapour is created upon a surface. This film can. Vapour may condense onto a cooled surface in two distinct modes known as filmwise and dropwise. For the same temperature difference between the vapour and the surface, dropwise condensation is several more times effective than is dropwise condensation and filmwise condensation?
|Published:||4 July 2015|
|PDF File Size:||38.3 Mb|
|ePub File Size:||48.53 Mb|
- Working of Water Softner
- What is film and drop wise condensation? - Quora
- Navigation menu
Dropwise condensation is useful in powerplant heat exchangers, thermal desalination, self-cleaning surfaces, and heating and air conditioning. The total amount of heat transfer through a single droplet is a function of its radius and the size distribution over the condensation surface.
The important factors which are involved in the film and dropwise condensation of heat transfer through a single droplets are: Thermal conduction through a single droplet Thermal conduction in the substrate material Interphase matter transfer at the vapour liquid interface Curvature of the vapour-liquid interface Cengel, Y.
Bejan, Convection heat Transfer, pp.
Wiley, New York Heat and Mass Transfer, vol. Miljkovic, N, Wang, E. The duplicate filmwise condenser is not specially treated and allows condensation to form as a film.
This effectively grows and runs down the condenser gaining thickness as it falls. The film effectively acts as a resistance to heat transfer, as heat must be conducted through this film to the internal cooling water.
Thermocouples are fitted to the surfaces of both condensers allowing the direct comparison of surface temperatures in both filmwise and dropwise condensation. Vocational Training HK Film and Dropwise Condensation Vapour may condense onto a cooled surface film and dropwise condensation two distinct modes known as filmwise and dropwise.
For the same temperature difference between the vapour and the surface, dropwise condensation is several more times effective than filmwise. However it involves special surface finishes or treatment in order to maintain dropwise condensation and for this reason, though desirable, it seldom occurs in real plant operation.
The process of dropwise condensation is enhanced by the special water cooled condenser surface finish that prevents wetting of the surface. Condensation then occurs in droplets which grow and fall under gravity.