Compressor speed

As the speed decreases and the flow rate drops, when the compressor flow reaches a certain level, surge occurs!

When the compressor speed changes, its performance curve also changes accordingly; therefore, this method can be used to adjust the operating point in order to meet the requirements of production adjustments. When the inlet flow rate to the compressor becomes low enough, severe rotational stall occurs throughout the diffuser flow channel. The outlet pressure of the compressor drops suddenly, causing the pressure in the pipeline network to be higher than the compressor’s outlet pressure; this forces the airflow to flow back into the compressor. Once the pressure in the pipeline network drops below the compressor’s outlet pressure, the compressor resumes supplying air to the pipeline network and returns to normal operation. When the pipeline pressure returns to its original level, the flow rate remains below the surge flow rate of the unit; the compressor experiences rotational stall again, the outlet pressure drops, and the airflow in the pipeline flows back into the compressor. This process repeats over and over: at times, air flow is directed into the pipeline system, and at other times it flows back to the compressor, causing significant fluctuations in the compressor’s flow rate and outlet pressure. These fluctuations result in intense air flow variations within the compressor, and this phenomenon is known as compressor surge. Generally, the larger the capacity of the piping network, the greater the surge amplitude and the lower the frequency; conversely, the smaller the capacity of the piping network, the smaller the surge amplitude and the higher the frequency.

The rotational speed decreases, and the flow rate drops. As the speed increases, the flow rate increases as well. It also needs to be adjusted in conjunction with the anti-surge valve.