半开式叶轮离心泵变叶顶间隙流动特性的研究  

Study on the Flow Characteristics of Variable Tip Clearance for Semi-open Impeller Centrifugal Pump

作　　者：张青扬 杨军虎[1] 李怀瑞 阎世杰 李瑶 ZHANG Qing-yang;YANG Jun-hu;LI Huai-rui;YAN Shi-jie;LI Yao(School of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Fluid Machinery and Systems,Gansu Province,Lanzhou 730050,China)

机构地区：[1]兰州理工大学能动学院,甘肃兰州730050 [2]甘肃省流体机械及系统重点实验室,甘肃兰州730050

出　　处：《液压气动与密封》2021年第6期1-6,共6页Hydraulics Pneumatics & Seals

基　　金：国家自然科学基金资助项目(51979135,51469014)。

摘　　要：为研究叶顶间隙的改变对半开式叶轮离心泵内部流场及性能的影响,选取某半开式叶轮离心泵进行全流道数值模拟。结果表明,不同相对间隙下叶轮内压力变化大体趋势一致,沿着叶轮进口到叶轮出口等压线周向呈均匀分布,且总压由叶轮进口向出口逐渐递增;随着相对间隙值增大,沿圆周方向叶轮流道内压力梯度逐渐减小,由于叶顶间隙增大使叶轮流道中高压流体沿着轴向的泄漏量增加引起叶片做功能力减弱,叶轮叶片出口处局部高压区逐渐减弱。在同一径向位置间隙层中靠近叶片工作面附近流体压力较背面大,且在叶片工作面与背面两侧间隙层存在较大的压力梯度。间隙层出口处存在局部高压区,随着间隙值的增大该局部高压区有所减弱,不同相对间隙值下相对速度沿径向均匀增大。叶轮轴向截面内存在着回流、绕流等不稳定流动,轴向截面中有明显的回流涡产生。叶片工作面(PS)高压流体横跨叶顶间隙从高压区向低压区泄漏并与相邻叶片背面流道主流相互掺混并在叶片背面(SS)形成较为明显的间隙泄漏涡(TLV),间隙泄漏涡的尺度随相对间隙值的增大而增大。In order to study the influence of the change of the tip clearance on the internal flow field and performance of the semi-open impeller centrifugal pump,a semi-open impeller centrifugal pump was selected for full-channel numerical simulation.The results show that the pressure changes in the impeller under different relative clearances are generally consistent,and are uniformly distributed along the isobaric line from the impeller inlet to the outlet,and the total pressure gradually increases from the impeller inlet to the outlet;As the relative tip clearance increases,the pressure gradient in the impeller flow path decreases along the circumferential direction.Due to the increase in the tip clearance,the leakage of the high-pressure fluid in the impeller flow path along the axial direction increases,which causes the blade to weaken its function.The impeller blade outlet The local high-pressure area gradually weakened.The fluid pressure in the tip layer near the blade pressure side in the same radial position is larger than that on the suction side,and there is a large pressure gradient between the tip between the blade pressure side and the suction side.There is a local high-pressure zone at the exit of the tip layer.As the tip clearance increases,the local high-pressure zone weakens,and the relative velocity increases uniformly in the radial direction at different relative tip clearances.In the axial section of the impeller,there are backflow and circumfluent unstable flows,and there are obvious backflow vortices in the axial section.The high-pressure fluid of the blade pressure side(PS)leaks from the high-pressure region to the low-pressure region across the tip clearance and blends with the main flow channel of the back surface of the adjacent blade and forms a more obvious tip leakage vortex(TLV)on the suction side(SS)of the blade.The size of the tip leakage vortex increases with the increase of the relative tip value.

关 键 词：离心泵 半开式叶轮 叶顶间隙 数值模拟 间隙泄漏涡 

分 类 号：TH137[机械工程—机械制造及自动化] TH311