脉冲对空化射流影响机理研究

Influence Mechanism of Pulse on the Cavitation Jet

由于脉冲对空化效果的作用机理尚不清晰、相关研究鲜有涉及,利用Visual Studio软件对Workbench Fluent进行二次开发,建立了空化喷嘴有限元计算模型,开展了不同脉冲射流类型、幅值和周期下的空化特性研究,揭示了脉冲射流对空化效果的影响规律。研究结果表明:脉冲射流对空化的形成具有较大促进作用,在出口淹没区域形成了第2次空化现象;不同脉冲类型形成的空化效果有明显的区别,适用于不同的工况;脉冲幅值越大,空化作用越强;脉冲周期对第1次空化影响较小,对二次空化影响较大,其中对低幅值脉冲二次空化作用影响较小,对高幅值脉冲二次空化作用影响较大,即随着脉冲周期的增长,高幅值脉冲二次空化作用显著减弱。研究结果可为指导空化射流类工具的设计以及工程应用中流体参数控制提供理论依据。

The mechanism of the effect of pulse on the cavitation is not clear, and there are few related researches presently.In this paper, Visual Studio software was used for secondary development of Workbench Fluent, the finite element calculation model of cavitation nozzle was established, cavitation characteristics of different pulse jet types, amplitudes and periods were studied, and the influence law of pulsed jet on cavitation effect was revealed.The results show that the pulsed jet can greatly promote the formation of cavitation, and the second cavitation phenomenon was formed in the flooded area of the outlet.The cavitation effect formed by different pulse types is obviously different, which is suitable for different working conditions.The larger the pulse amplitude, the stronger the cavitation effect.Pulse period has a small effect on the first cavitation, but a great effect on the second cavitation.For the second cavitation of low-amplitude pulse, pulse period has a small effect;while for the second cavitation of high-amplitude pulse, pulse period has a great effect.That is, with the increase of the pulse period, the second cavitation of the high-amplitude pulse is weakened significantly.The results provide a theoretical basis for the design of cavitation jet tools and the control of fluid parameters in engineering applications.