Compressor inlet pressure
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It is generally required that the compressor maintain its compression ratio during normal operation. What I want to ask is whether it is sufficient for the compression ratio to remain constant. For example, if the compressor’s compression ratio is 2, with an inlet pressure of 4 and an outlet pressure of 8 under normal conditions, and in case of some issue the inlet pressure drops to 2 while the outlet pressure remains at 4, the compression ratio will still be 2. Will this have any impact on the compressor?
It is also necessary to ensure its inlet flow rate, inlet pressure, etc
What is the guaranteed value? Is it the rated design value or something else?
+ The inlet pressure has a design value; it falls within a certain range. A constant compression ratio is ideal, but you also need to ensure the inlet flow rate to avoid surge.
It is necessary to maintain the inlet pressure; if the inlet pressure is low, insufficient flow can cause compressor surge.
It is necessary to maintain the inlet pressure; if the inlet pressure is low, insufficient flow can cause compressor surge.
Two points: 1. Since gases generally have high compressibility, for a given compressor, the inlet pressure and flow rate are usually related to each other； 2. For centrifugal compressors, including fans, the methods for adjusting flow rate include adjusting the rotational speed, adjusting the flow rate after compression, using backflow control, and throttling before the compressor. Among these, installing valves or vanes before the compressor to carry out adjustments (this is the most economical and common method of adjustment) corresponds to the approach of regulating the flow rate by reducing the inlet pressure. Therefore, as long as the flow rate remains at least the minimum value corresponding to its rotational speed, there is no significant impact on the compressor other than a reduction in power consumption.
As long as it is within the normal operating range, any pressure ratio is acceptable
Compressors come with a specified pressure rating at the time of manufacture; normal operation should take place within this range. Moreover, the pressure ratio is not calculated based on the actual inlet and outlet pressures – an additional 0.1 should be added to these pressures. For example, if the inlet pressure is 2 bar and the outlet pressure is 4 bar, then the pressure ratio should be (0.4 + 0.1) / (0.2 + 0.1)