Compressor speed
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I want to know the specific relationship between the compressor speed and the air delivery volume, as well as the shaft power.
From a theoretical qualitative analysis, for centrifugal compressors, the higher the rotational speed, the greater the air displacement and the greater the power required； Conversely, the lower the rotational speed, the smaller the air compression volume, and the less power is required.
For reciprocating compressors, comparisons of speed should be made among models of the same size. For example, the MH92 and MH73 models have identical dimensions and their components can be used interchangeably; however, their speeds differ, which results in different air delivery rates as well as different shaft power and motor power requirements.
The formula for calculating the air delivery volume of a compressor is V = (3.14D²/4) × L / λ. In this formula: V represents the air delivery volume in cubic meters per minute; D is the diameter of the piston, in meters; L is the piston stroke length, in meters; i is the number of times the piston draws in gas per cycle; n is the rotational speed, in revolutions per minute; and λ is the gas transfer coefficient. It can be seen from this formula that, whether it is a centrifugal compressor or a piston compressor, its air delivery volume is directly related to its rotational speed.
The formula provided by the moderator upstairs is for calculating the air delivery volume of single-acting reciprocating compressors; nowadays, double-acting compressors are more common. The formula is as follows: Q = π/4 × (2D² – d²) × L × n × λ × 2. Here, Q represents the volume of air to be compressed; D is the diameter of the cylinder; d is the diameter of the piston; L is the piston stroke; n is the number of revolutions per minute of the compressor; and λ is the compression ratio