液环泵叶片轴向叶顶凹槽间隙流场及其性能

Axial leakage flow and performance analysis of squealer tip clearance for liquid ring pump blade

为改善液环泵轴向叶顶间隙泄漏流场结构,提升液环泵水力性能,提出液环泵叶片轴向叶顶凹槽结构设计,以2BEA-203型液环泵为研究对象,采用数值模拟方法分析液环泵叶轮轴向间隙泄漏流动及其与主流的相互干扰作用,对比分析凹槽叶顶与平顶间隙泄漏流动及其性能.分析结果表明,液环泵内流动呈现复杂的三维结构,凹槽型叶顶间隙能够在一定范围内提升液环泵的效率及真空度,在大流量点0.07 kg/s时的吸入真空度相对平顶型叶片提升5.26%,其他各流量点真空度及效率也略有提升;凹槽型间隙除在凹槽内产生凹槽涡及凹槽角涡外,在叶片压力面叶顶处角涡及叶片吸力面后方的泄漏涡结构与叶片平顶型间隙基本相似.轴向叶顶压力面附近角涡及吸力面后方的泄漏涡强度由轮缘到轮毂逐渐增强,凹槽型轴向叶顶能够在一定程度上减弱角涡及泄漏涡量的分布;在气相分布区域,叶顶间隙泄漏涡强度明显高于液相分布区域.由于凹槽的缓冲作用,使得间隙内及叶片吸力面后方的泄漏流速、湍流强度及总压损失均有一定程度的减小,达到提升泵的吸入真空度和效率的目的.

In order to improve the leakage flow structure of the axial tip clearance and improve the hydraulic performance of the liquid ring pump,the axial squealer tip of the liquid blade was designed.Taking the 2BEA-203 liquid ring pump as the research object,the numerical simulation method was used to analyze the leakage flow of the axial clearance of the impeller of the liquid ring pump and its interaction with the main flow.The leakage flow and performance for both the squealer tip and the flat tip were compared.The results show that the flow in the liquid ring pump presents a complex three-dimensional structure,and the squealer tip clearance can improve the efficiency and vacuum within a certain range.When the flow rate is 0.07 kg/s,the vacuum is 5.26%higher than that of flat tip blade,and the vacuum and efficiency of other flow rate conditions are also slightly improved.The structure of the angular vortex near the tip blade pressure surface and the leakage vortex behind the blade suction surface of the blade is basically similar to that of the flat tip blade except the squealer vortex and squealer angular vortex in the squealer.The strength of the angular vortex near the blade pressure surface and the leakage vortex behind the blade suction surface of the axial blade tip increase gradually from the rim to the hub,and the strength of the angle vortex and the leakage vortex can be weakened to some extent by axial squealer tip blade.In the region of gas distribution,the strength of tip leakage vortex is higher than that of liquid distribution.Due to the buffer effect of the squealer,the leakage velocity,turbulence intensity and total pressure loss in the clearance and behind the blade suction surface are reduced to a certain extent,so the suction vacuum and efficiency of the pump are improved.