This calculation is based on the definition of the pressure coefficient and the definition of the polytropic work. “Pressure ratio is how much pressure the compressor stage will generate at a given speed relative to atmospheric pressure along with inlet conditions (filter restrictions). Compressor Ratio Math.. :/ If you really want to know the math behind the settings I’ll do my best here to explain it a little. If the compressor is functioning properly the higher the compression ratio the fewer pounds of refrigerant is being moved and the lower the compression ratio the more pounds are moved. Compressor manufacturers can tell you what the maximum compression ratio is for a specific compressor, but an accepted rule is no more than a 10:1 compression ratio. Thanks to the head coefficient it is possible to calculate which compression ratio will be given by an impeller. The power of a compressor surge is also proportional to the capacities (flow, power, pressure ratio) and even in the case of small turbo compressors, the gear teeth wear out when the impeller rotates in the opposite direction during a surge. Compression ratio (R) is the ratio of discharge pressure (Р 2) to suction pressure (Р 1) in compressor, Р2/Р1. So.. 13.3.As discussed previously, a decrease in compressor pressure ratio is observed. Pressure ratio is used instead of boost because atmospheric pressure changes with altitude and … The trends in pressure ratio during compressor fouling are shown in Fig. One of the critical parameters in compressor design and selection is the compression ratio, often denoted as r. The compression ratio is simply the ratio of the absolute stage discharge pressure to the absolute stage suction pressure.. Because most gases increase in temperature when they are compressed, the final compressor outlet temperature is always a concern. The bottom line is: Always avoid a surge in compressors and other rotating equipment. If you have the ratio set to 3:1 and the threshold is set to -10dbs, for every 3dbs your audio goes over the threshold it’s only going to allow 1db to actually pass. When compression to higher pressures is required, compressor calculation assumes several compression stages; in some cases coolers are required to remove heat between compression stages. The thermal efficiency in terms of the compressor pressure ratio (PR = p 2 /p 1), which is the parameter commonly used: In general, increasing the pressure ratio is the most direct way to increase the overall thermal efficiency of a Brayton cycle, because the cycle approaches the Carnot cycle. 4. Compression ratio calculation. In order to determine a system’s compression ratio, we must deal in absolute pressures, not gauge pressure readings, since a refrigeration system is a closed system, not open to atmospheric pressure.