多级降压调节阀内部流动特性数值模拟

为研究多级降压调节阀内部流动过程和各降压级的压降影响因素及规律，基于Mixture两相流模型和Schnerr-Sauer空化模型的数值计算方法，建立了多级降压调节阀内部流场的计算模型。通过数值模拟计算，获得了调节阀内部的流动特性，分析和探讨不同压差和不同阀门开度下各降压级压降特性。数值计算结果表明:流体流经阀门节流元件时，由于多股流体的强烈掺混和剪切使得阀门内存在大量的漩涡；各降压级的压降存在一定的差异，第3级套筒处的空化程度最大，阀座处更易发生空化；阀门在同一开度下，工质沿各降压级的压降在不同压差下的变化趋势相同；第3降压级的压降随阀门开度的减小而增大，在25%开度下阀门第3降压级的平均压降最大，达到了8 MPa，相同流量下该降压级小孔中工质的速度也增加。研究结果为降压阀的合理设计提供了理论依据和参考价值。 

Numerical simulation on internal flow performances of multi-stage pressure drop valve

To study the internal flow process of the multi-stage pressure drop valve and the influencing factors and influence laws of the pressure drop of pressure-drop-stage, based on the numerical calculation method of the Mixture two-phase flow model and the Schnerr-Sauer cavitation model, the calculation model of the flow field of a multi-stage inside the valve was established. The flow characteristics inside the pressure drop valve are obtained through numerical simulation calculation, and the impact of various pressure differences and various opening degrees of the valve on the pressure drop of each pressure-drop-stage is analyzed and discussed. Numerical calculation results show that there are a large number of vortices in the valve due to the vigorous mixing and shear of multiple fluids when the fluid flows through the throttle element of the valve. The pressure drop of each pressure-drop-stage is different, and the degree of cavitation of the third stage sleeve is the largest, cavitation is more likely to occur at the valve seat. The pressure drop of the working fluid along each pressure-drop-stage exhibits the same changing trend at the same opening degree of the valve under various pressure differences. The pressure drop of the third pressure-drop-stage rises when the opening degree of the valve is reduced. The average pressure drop of the 3rd pressure-drop-stage reaches 8 MPa at the opening degree of 25%. The velocity of working fluid in the small hole of the pressure-drop-stage also increases under the condition of the same mass flow rate. This paper provides the theoretical basis and reference value for the designs of the pressure reducing valve.