Q1: With increase in compression ratio, the volumetric efficiency of air compressor

ANS:A - increases.

With an increase in compression ratio, the volumetric efficiency of an air compressor typically increases.. Explanation:

1. Compression Ratio: Compression ratio is defined as the ratio of the absolute discharge pressure to the absolute suction pressure in the compressor cylinder. As the compression ratio increases, the discharge pressure becomes higher relative to the suction pressure.
2. Volumetric Efficiency: Volumetric efficiency of a compressor is the ratio of the actual volume of air delivered by the compressor to the theoretical volume that would be delivered if the compression process were isentropic (ideal and without losses). It is a measure of how effectively the compressor is able to compress a given volume of air.
3. Effect of Compression Ratio on Volumetric Efficiency: As the compression ratio increases, the compression process becomes more difficult, especially in positive displacement compressors such as reciprocating compressors. Higher compression ratios lead to increased compression work, higher temperatures, and increased clearance volume losses. These factors contribute to reduced volumetric efficiency because the compressor is less effective at delivering the desired volume of air per unit of time.
4. Other Factors: While the suction pressure may also influence the volumetric efficiency to some extent, in general, an increase in compression ratio tends to have a dominant effect on decreasing volumetric efficiency due to the reasons mentioned above.