Assertion (A): Drop-wise condensation is associated with higher heat t...
Assertion (A): Drop-wise condensation is associated with higher heat transfer rate as compared to the heat transfer rate in film condensation.
Reason (R): In drop condensation there is free surface through which direct heat transfer takes place.
Explanation:
Drop-wise condensation and film condensation are two different modes of condensation that occur when a vapor comes into contact with a cooler surface.
Drop-wise condensation: In drop-wise condensation, individual droplets are formed on the surface and grow in size as more vapor condenses. These droplets eventually detach from the surface due to gravity or other forces. This mode of condensation is characterized by the presence of discrete droplets on the surface.
Film condensation: In film condensation, a thin film of condensate forms on the surface and flows downwards due to gravity. This mode of condensation is characterized by a continuous film of condensate on the surface.
Now let's analyze the given assertion and reason:
Assertion (A): Drop-wise condensation is associated with higher heat transfer rate as compared to the heat transfer rate in film condensation.
Reason (R): In drop condensation there is free surface through which direct heat transfer takes place.
Both the assertion and reason are individually true.
Explanation of Assertion (A):
Drop-wise condensation is associated with higher heat transfer rate compared to film condensation. This is because in drop-wise condensation, each individual droplet provides a separate surface for heat transfer. The droplets can quickly grow in size and detach from the surface, allowing new droplets to form and continue the condensation process. This continuous formation and detachment of droplets result in increased heat transfer rate as compared to film condensation where a continuous film of condensate slows down the heat transfer process.
Explanation of Reason (R):
In drop-wise condensation, there is a free surface through which direct heat transfer takes place. Each droplet formed on the surface acts as a separate interface for heat transfer. The vapor condenses on the surface of the droplets and releases heat, which is transferred directly to the droplets. This direct contact between the droplets and the vapor allows for efficient heat transfer.
Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion. Drop-wise condensation indeed has a higher heat transfer rate compared to film condensation due to the presence of discrete droplets providing direct heat transfer surfaces.
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