阀套开槽对二维阀空化噪声的抑制

Cavitation Noise Suppression of 2D Valve by Valve Sleeve Slotting

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。针对二维阀先导级的空化流动,采用计算流体力学方法进行分析。以二维阀先导级结构为研究对象,利用Fluent软件进行数值模拟,对比研究不同阀套结构下阀内流场的流速变化、压力分布、气体体积分数等流动特征。结果表明,在阀套斜槽两侧面开U形槽后,空化现象有所减弱,表现为分析面的射流速度降低,斜槽底面的气体体积分数下降,说明开U形槽后,改变了阀套斜槽内的速度流线,削弱了高速射流流体剪切流动的效果。通过进一步分析阀套斜槽内所设监测点的噪声频谱,发现阀套斜槽两侧面开U形槽结构与原结构相比,在斜槽区空化最严重的后部,噪声降低了10 dB;在模型出口处,噪声降低了3 dB;在斜槽中部,噪声声压级略有增加。说明在阀套斜槽两侧面开宽深比为2.2的U形槽确实能降低二维阀先导级因空化引起的噪声。

The pilot stage and the power stage are integrated in one spool by the 2D valve,which is easy to realize the fast work and high frequency response of the valve.It has the advantages of simple structure,stable performance and large power to weight ratio.The cavitation flow in the pilot stage of the 2D valve was analyzed by computational fluid dynamics.Taking the 2D valve pilot structure as the research object,Fluent software was used to compare the flow rate change,pressure distribution,gas volume fraction and other flow characteristics under different valve sleeve structures.The results show that the cavitation phenomenon is weakened after opening U-shaped grooves on both sides of the valve sleeve chute,which shows that the jet velocity on the analysis surface decreases and the gas volume fraction on the bottom surface of the chute decreases,indicating that the U-shaped grooves change the velocity streamline in the valve sleeve chute and weaken the shear flow effect of high-speed jet fluid.By further analyzing the noise spectrum of monitoring points in the valve sleeve chute,it is found that the noise of the two sides of the valve sleeve chute is reduced by 10 dB in the back of the chute where the cavitation is most serious compared with the original structure;at the exit of the model,the noise is reduced by 3 dB;in the middle of the chute,the noise sound pressure level increases slightly.It shows that the U-shaped groove with a width to depth ratio of 2.2 on both sides of the valve sleeve chute can indeed reduce the noise caused by cavitation in the 2D valve pilot stage.