Air Compressor Cycles

1 Pages 336 Words

My PV diagram did not take the shape that I expected. The basic shape was what I expected, but where the 2nd stage starts I thought there would be more of a volume increase at V1 but there was in fact a slight decrease. Maybe this was because there was a slight time lapse before the computer recorded the reading.

There were differences between the theoretical results and my observed readings.
The efficiency is made worse if leaks occur past the valves or the piston. Ideally the processes between 1 and 4 and 2 to 3 are isothermal ie no temp change. It is hard to say if this was the case but from the graph it does seem to be overall.

In reality the warm cylinder would cause a slight temperature rise over the induction from 4 to 1. The gas is restricted by the valves and they tend to move slightly so P1 was probably slightly less than P4.

Altering the value of the polytropic index would have an effect on the compressor performance. IF n equalled 1 then it would be iso thermal so the higher the better as we want it to be polytropic, a slight increase in the polytropic index would increase the performance.

Multi stage cooling would improve the efficiency of the compressor. If the air is cooled then it takes up less room which means less work is required to achieve the compression ratio. This would increase the overall efficiency of the compressor.

The hazards that could effect compressor performance are several.
Oil in air dieseling- If oil gets present in the air then an effect known as dieseling can occur where the temperature of the air after compression is sufficient to ignite the oil air mixture.

Effects of water in the air.
Water is always going to be present in air but blow down valves deal with this. If large amounts enetered the air though, from a leak etc. then this could cause locking of the plungers in the barrels and cause major damage to the compressor....