Consider the following statements;

The presence of air inside condensers

1) Remains as a non-condensable gas

2) Reduces the condensing coefficient

3) Tends to cling to the surface

4) Introduces large thermal resistance
Which of the above statements are correct?

Question

Question

This question was previously asked in

ESE Mechanical 2017 Official Paper

Answer 1

Explanation:

The performance of condenser gets affected badly by presence of air which will remain non condensable.
It covers the heat transfer surfaces such as outside the surface of condenser tubes and reduces the condensing heat transfer coefficient.
Clinging of air to surface reduces the condensing coefficient
air imparts large thermal resistance due to its low thermal conductivity