全射流喷头射流元件附壁频率

基于全射流喷头射流元件的工作原理和内部流动状况,分析射流元件附壁频率的影响因素.利用元件两侧压差大小,建立附壁频率计算式,通过射流元件壁面脉动压力测量获得的附壁频率试验数据,频率计算值与试验值符合较好.计算与试验结果表明,附壁频率随元件腔室容积增大,信号水导管长度的变长而减小,随喷头工作压力增大,信号水流量的增大而增大,对于PXH30全射流喷头射流元件,获得信号水流量与附壁频率的线性关系式.在无因次数计算与分析中,喷嘴雷诺数对斯特劳哈数影响较小,斯特劳哈数随欧拉数的增大而减小.附壁频率的研究能指导射流元件的设计和全射流喷头工作状态的调节.

Wall attachment frequency of complete fluidic sprinkler′s fluidic element

Based on the working principle of complete fluidic sprinkler′s fluidic element and its inner flow state, factors that affect the frequency of wall attachment offset jet are analyzed. A calculating formula of frequency is established by the differential pressures on both sides of fluidic element. The wall fluctuating pressures of fluidic element are measured and converted to the experimental data of wall attachment frequency. The calculating results of frequency agree well with the experimental data. Both the experimental data and the calculating results show that the frequency decreases with the signal pipe length and increases with the fluidic element′s cavity volume. The frequency increases with the sprinkler′s working pressure and the flow rate of signal water. As far as the type of PXH30 sprinkler is concerned, the wall attachment frequencies are linear with the flow rate of signal water. The Reynolds number has little influence on the Strouhal number, and the Strouhal number reduces with the Euler number increasing. The study provides the guide for the design of fluidic element and the adjustment of sprinkler′s working state.