基于FLUENT的二维阀空化与压力脉动的特性研究

Characteristics of cavitation and pressure fluctuation of a two-dimensional valve based on FLUENT simulation

二维阀将先导级和功率级集成在一个阀芯上,易于实现阀的快速工作和高频响应,具有结构简单、性能稳定、功重比大等优点。其先导级节流口引发的空化现象,是致二维阀压力脉动、振动和噪声的重要原因。通过数值计算,对阀口一个启闭周期内流场的空化特性和压力脉动进行分析可知:二维阀先导级流场中,节流口下游一侧的阀套斜槽区是空化发生的主要区域;阀口闭合一侧节流口处的速度最大值(108 m/s)高于开启侧节流口处的速度最大值(97.8 m/s),且高速持续时间长了0.2 s;阀口开启时程的空化程度严重,受此影响,闭合时程的空化区域面积较大;二维阀先导级流场的空化会引起压力脉动,近壁面压力脉动集中在50 Hz以内,阀套斜槽内的压力脉动呈宽频特性。

The pilot stage and power stage of a two-dimensional valve are integrated into one spool,which makes easy to realize the fast operation and high frequency response of the valve.Such kind of valve has the advantages of simple structure,stable performance and high power to weight ratio.The cavitation caused by the pilot orifice is an important cause of pressure pulsation,vibration and noise.Through numerical calculation,the cavitation characteristics and pressure pulsation of the flow field in an opening and closing period of the valve port were analyzed.It can be seen that in the flow field of the pilot stage of the two-dimensional valve,the chute area of the valve sleeve at the downstream of the throttle port is the main area where cavitation occurs.The maximum speed at the throttle port on the closed side(108 m/s) is higher than that on the open side(97.8 m/s),and the high speed duration is 0.2 s longer.The cavitation degree in valve opening is serious,and due to that,the cavitation area in valve closing is large.The cavitation of the flow field in the pilot stage of the two-dimensional valve will cause pressure pulsation.The pressure pulsation near the wall is concentrated at the frequency within 50 Hz,and the pressure pulsation in the chute of the valve sleeve shows broadband characteristics.