基于分段四次速度矩分布的叶片式气液混输泵导叶设计方法

Design Method of Diffuser in Rotodynamic Multiphase Pump Based on Fourth-order Distribution of Velocity Moment

叶片式气液混输泵是深海油气资源开采的核心装备,导叶对其输运性能影响较大,而混输泵导叶设计相关的研究很少。提出一种基于分段四次速度矩分布的叶片式气液混输泵导叶设计方法,利用三段四次函数控制导叶速度矩的分布规律,通过给定控制点流线长度及载荷等参数确定分布规律。将该设计方法应用到三级叶片式气液混输泵中,并选取轮毂前控制点载荷L_(1h)、轮毂前后控制点载荷差ΔL_(h)、轮缘前控制点载荷L_(1s)、轮缘前后控制点载荷差ΔL_(s)、前控制点流线长度m_(1)、后控制点流线长度m^(2)、起点载荷系数k_(0)等7个参数,对混输泵导叶进行7因素3水平的L_(18)(3^(7))正交优化。完成混输泵导叶设计和优化后,泵效率在单相和两相工况下分别平均提升6.73%和4.10%。优化前后的流场显示,导叶内流场低速区范围明显缩小,流动分离的范围和强度都受到了明显抑制。

Rotodynamic multiphase pumps are the key equipment for exploitation of deep-sea oil and gas resources,and the geometry of diffuser is a significant factor for transporting performance.A blade design method based on segmented fourth-order distribution of velocity moment is proposed in the present work.The distribution of diffuser velocity moment is controlled by three-stage fourth-order polynomial functions,and this distribution law is determined according to parameters of control points and corresponding point.This design method is applied to a three-stage rotodynamic multiphase pump.The seven parameters of loading at hub former control point location L_(1h),loading difference between hub former and latter control pointsΔL_(h),loading at shroud former control point location L_(1s),loading difference between shroud former and latter control pointsΔL_(s),former control point m_(1),latter control point m^(2),start loading coefficient k_(0)are selected,and an orthogonal optimization of 7 factors and 3 levels L_(18)(3^(7))is carried out for diffuser geometry.After design and optimization of diffuser,the pump efficiency under single-phase and multi-phase conditions are improved by 6.73%and 4.10%,respectively.The comparison between flow fields before and after optimization shows that,the range and degree of flow separation in diffuser have been suppressed.