How does dropwise condensation differ from film condensation which mode of condensation is characterized by larger heat transfer rates?
Which mode of condensation is characterized by larger heat transfer rates? Dropwise condensation heat transfer rates are more than an order of magnitude larger than those associated with film condensation.
Why is there condensation in dropwise?
Dropwise condensation occurs when a vapor condenses on a surface not wetted by the condensate. For nonmetal vapors, dropwise condensation gives much higher heat transfer coefficients than those found with film condensation.
What is condensation and explain in detail drop and film wise condensation?
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. Generally, film wise condensation results in low heat transfer rates as the film of condensate impedes the heat transfer.
Is dropwise condensation stable?
We demonstrate stable dropwise condensation of ethanol and hexane on LISs impregnated with Krytox 1525, attaining about 200% enhancement in condensation heat transfer coefficient for both fluids compared to filmwise condensation on hydrophobic surfaces.
Why is dropwise condensation better than Filmwise?
Implications for Heat Transfer Under certain conditions, dropwise condensation provides for much higher heat transfer rates than filmwise condensation. Although a drop has a larger surface area than a film occupying the same surface area, this difference is relatively small.
What is condensation and when does it occur distinguish between mechanism of Filmwise condensation and dropwise condensation?
The rate of condensation is higher. The filmwise condensation occurs on less polished and uncontaminated surfaces. The dropwise condensation requires a highly polished surface or the surface with promoters coating. The size of the equipment for filmwise condensation is larger for the unit rate of condensation.
Which is better dropwise or Filmwise condensation?
What is the difference between film and dropwise condensation chegg?
Which type of condensation is more effective?
Dropwise condensation
Dropwise condensation is one of the most effective mechanism of heat transfer and extremely large heat transfer coefficients can be achieved with this mechanism.
Why the rate of heat transfer in dropwise condensation is many times that of film condensation?
Why is heat transfer coefficient high in dropwise condensation?
Why the rate of heat transfer in dropwise condensation is many time that of film condensation?
What is the difference between Filmwise and Dropwise condensation?
The dropwise condensation has a much higher rate of heat transfer than filmwise condensation because the condensate in dropwise condensation gets removed at a faster rate leading to better heat transfer between the vapour and the bare surface. . It is therefore desirable to maintain a condition of dropwise condensation 1D commercial application.
Where does Dropwise condensation occur?
Dropwise condensation can only occur either on highly polished surfaces or on surfaces contaminated with certain chemicals.
What determines the thickness of the film formed by condensation?
The thickness of the film formed depends on many parameters including orientation of the surface, viscosity, rate of condensation etc. Drop-wise condensation takes place when the surface over which condensation takes place is non wet-able.
What is the effect of gravity on continuous film of liquid?
(i) the continuous film of liquid will flow downward (positive X-axis) under the action of gravity and its thickness would increase as more and more vapour condenses at the liquid – vapour interface, (ii) the continuous film so formed would offer a thermal resistance between the vapour and the surface and would reduce the heat transfer rates,