The meaning of pneumatic shock wave

Pneumatic shock wave supersonic flow has a very wide range of applications in aerospace, electric power, chemical industry, refrigeration, and nuclear industries. In recent years, with the popularity of jet heat pumps that use low-temperature and low-pressure heat sources, steam jet pumps appear in modern nuclear power plant safety engineering. With a good application prospect, the vigorous promotion of low-temperature multi-effect evaporative seawater desalination technology (MED-TVC) with TVC (vapor compressor) devices has promoted people’s understanding of the supersonic flow characteristics of steam and the energy exchange and The requirements and interest of the mechanism research on the influence of the phase change process on the ejector performance.

The ejector relies on the mutual mixing, collision, and friction between fluids to transfer energy. The internal flow process is very complicated, and there are extremely complicated flow phenomena such as supersonic flow, turbulence, entrainment mixing, and shock waves. The occurrence of these unbalanced and unsteady flow phenomena makes the flow process inside the ejector very complicated. The strong compressibility of fluid in supersonic flow will show many different characteristics from subsonic speed, especially the appearance of compression wave or expansion wave, which will have a great influence on flow parameters. Especially in the low-temperature multi-effect evaporation (LT-MED) seawater desalination system, the working state of the steam ejector (TVC) will affect the efficiency and water production ratio of the entire system. Therefore, it has important theoretical significance and engineering value to carry out the characteristic analysis of the steam supersonic flow field, the shock wave effect capture and the pneumatic shock wave dissipation effect research in the ejector.