基于缝隙射流原理的离心泵空化控制研究

为了改善低比转速离心泵内的空化流动状态，提出一种在叶片上设置缝隙的被动控制方法，探究该结构对空化的抑制效果及其控制机理. 采用数值模拟方法探讨结构对空化的抑制. 采用修正的SST k-ω湍流模型和Kubota空化模型，对原始叶轮和改型叶轮分别进行定常及非定常数值计算，获得设计工况下2种叶轮形式在各个空化阶段的流场结构及压力脉动特性. 计算结果表明：改型叶轮中经缝隙流向叶片背面的高压流体提高了叶片背面的压力，对空化初生、空化发展及空化剧烈阶段均产生了抑制作用，特别是空化剧烈阶段，与原始叶轮相比，其空泡体积分数减少了60.6%；与原始叶轮相比，改型叶轮内液相区的压力脉动主频幅值在各个空化阶段均有所下降.

Cavitation control of centrifugal pump based on gap jet principle

A passive control method with slot on the blade was proposed, and the cavitation suppression effect and control mechanism of the structure were explored, in order to improve the cavitation flow state in low specific speed centrifugal pump. The restraining effect of the structure on cavitation was explored by numerical simulation method. The modified SST k-ω turbulence model and Kubota cavitation model were used to calculate the steady and unsteady flow on the original impeller and the modified impeller, respectively, to obtain the flow field structure and pressure pulsation characteristic of two impeller forms in each cavitation stage under the design conditions. The calculation results show that the high-pressure fluid flowing to the back of the blade through the gap in the modified impeller increases the pressure on the back of the blade, which has inhibitory effect on initial cavitation, the development of cavitation and the intense stage of cavitation. Especially for the intense stage of cavitation, the cavity volume fraction decreased by 60.6% compared with the original model. the main frequency amplitude of the pressure pulsation in the liquid region of the modified impeller decreased at each cavitation stage, compared with that of the original impeller.