口环间隙对高速泵泵腔内流动特征的影响

Effects of wear-rings clearance on flow characteristic in impeller side chamber of high-speed centrifugal pump

为分析泵腔内流场结构及口环间隙变化对高速泵在设计工况下性能的影响,基于雷诺时均N-S方程及RNG k-ε湍流模型的理论基础,以转速n=38 500 r/min的离心泵为研究对象,对其进行全流场数值模拟.结果表明,前后泵腔内u_t/u均随着半径的增加而减小;沿着叶轮旋转方向u_t/u也不断减小,在α=0°即蜗壳隔舌附近时u_t/u值最小.在前后泵腔内,靠近盖板的区域u_r/u>0;靠近壳体的区域u_r/u<0.前、后口环间隙分别对前、后腔流场结构的影响基本一致:在同一轴向位置处,随着口环间隙的增大,流动核心区的u_t/u增大,靠近壳体一侧的u_r/u减小;在同一半径位置,口环间隙越大,静压越小.

In order to analyze the flow characteristic in the impeller side chamber and the effect of wear-rings clearance modifications on it, the RNG k -ε turbulence model is employed in the Reynolds averaged Navier- Stokes equations in this study. A high-speed centrifugal pump with a speed of 38 500 r/min in a design condition was studied using CFD method. The results show that u/u decrea- ses with the increase of the radius in the front and back impeller side chamber; ui/u also constantly decreases in the impeller rotation direction and reaches the minimal value at α = 0° （ near the volute tongue）. Near the shoulder side of front as well as back impeller side chamber, their exists Ur/U 〉0; while near the stator side of front as well as back impeller side chamber, there exists ui/u 〈 0. The effects of the front wear-rings clearance and rear wear-rings which are separately imposed on the flow field structure of field structure of the front and back impeller side chamber are mainly coincident： at the same axial location,with the increase of the wear-rings clearance, ui/u of the core flow region in- creases; ui/u close to the stator side decreases; at the same radius, the larger the wear-rings clea- rance, the lower the static pressure.