Compressor volumetric flow rate
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I read online that the volumetric flow rate is also referred to as the displacement or nameplate flow rate in China. Put simply, at the required exhaust pressure, it refers to the volume of gas discharged by the air compressor per unit of time; when converted to the intake conditions, this is the volume value at the intake pressure and under the corresponding intake temperature and humidity at the first-stage intake connection. The unit is m3/min. Does the displacement indicated on the nameplate of reciprocating compressors and centrifugal compressors refer to the same value for screw compressors as well? Are there still differences among various compressors?
Some sources on the Internet state that it should be converted to standard conditions, where the temperature is 20°C, the altitude is 0 meters, the air humidity is 0, and the pressure is 1 standard atmosphere – this represents the amount of air that the air compressor draws in through its intake. Some say it should be converted to the intake condition, that is, the suction pressure at the intake connection of the first stage (design condition), along with the volume value corresponding to the suction temperature and humidity. These two concepts are not the same; what do you think?
It should be the amount of gas drawn in by the compressor from the intake port under standard conditions (1 standard atmosphere and 20°C).
The nameplate flow rate should be converted to the flow rate at standard conditions.
The volumetric flow rate of screw air compressors is also referred to in China as the exhaust volume or nameplate flow rate. Put simply, at the required exhaust pressure, it refers to the volume of gas discharged by the air compressor per unit of time; when converted to the intake conditions, this is the volume value at the intake pressure and under the corresponding intake temperature and humidity at the first-stage intake connection. The unit is m3/min. It’s not a standard situation. What does a centrifugal compressor look like?
I believe that the rated discharge volume of Shenmu reciprocating compressors refers to the volume of gas at the inlet connection point under the conditions of the inlet pressure, temperature, and humidity at the design condition. As for the rated discharge volume of Shenmu centrifugal compressors, it represents the amount of gas drawn in by the compressor under standard conditions (1 standard atmosphere and 20°C). I have arrived at this figure through calculations; I’m not sure if this is the standard way of expressing it
Special gases are generally imported and not in standard conditions； If it is an air compressor, when the intake pressure is at atmospheric pressure, it should be under standard conditions.
Standard conditions: Abbreviation for standard conditions. Abbreviated as STP. It usually refers to conditions where the temperature is 0°C (273.15 Kelvin) and the pressure is 101.325 kPa (1 standard atmosphere, 760 millimeters of mercury), providing a uniform standard for comparing gas volumes.
Regarding this volumetric flow rate. I have a question: for a compressor with a fixed frequency, assuming that parameters such as volumetric efficiency remain unchanged, should the volumetric flow rate of air drawn in by the compressor be constant?
Thank you to the original poster for their comments on my reply. I’d like to delve deeper into this topic with you. 1. In a compressor in actual operation, does the volumetric efficiency change depending on operating conditions, and if so, is the extent of that change significant? 2. The original poster specifically emphasized that it is a reciprocating compressor. Can it be assumed that the volumetric flow rate of intake air remains constant for other types of compressors as well? 3. What type of compressor is most commonly used in refrigeration systems today?
You can tell just by looking at the unit: NM3/h refers to standard cubic meters, at standard atmospheric pressure and 0 degrees Celsius. . . . m3/min is the inlet flow rate