不同叶片包角的离心泵试验与数值模拟

EXPERIMENT AND NUMERICAL SIMULATION OF CENTRIFUGAL PUMP WITH DIFFERENT WRAP ANGLE

在离心泵叶轮的基本外尺寸(叶轮内外半径、叶轮进出口宽度、叶片进出口安放角及叶片数)和设计转速相同的情况下,采用三次曲线对叶片进行造型。设计叶片包角分别为59°、75°和91°的三副离心叶轮C1、C2、C3,其中叶轮C1与传统的单圆弧叶型非常接近。三副叶轮的同台试验结果显示,叶轮C2的最高效率比叶轮C1、C3的效率高1.28%、1.43%。采用数值模拟得到设计工况下三副叶轮内的相对速度场和各流道内的载荷分布,C1叶轮内有明显的回流区,且各流道内的载荷存在较大差异。研究表明:在叶轮外尺寸相同的情况下对叶片造型设计时,存在最佳的叶片包角,单圆弧叶型不是最佳叶型。

Centrifugal impellers C1, C2 and C3 are designed by using of three-order blade profile with the same basic geometry, such as radius, blade width and angle in the inlet and outlet, the number of the blades, and the designed rotating speed is also the same. The wrap angle of C1, C2 and C3 is 59°, 75° and 91° respectively. The profile of impeller C1 is very close to the ones of traditional single-arc. The test results indicate that the best efficiency of C2 is 1.28%, 1.43% higher than C1 and C3 respectively. By numerical simulation at the designed flow rate, the distribution of the relative velocity and load in the impeller is obtained. In the impeller C 1 there is recirculation flow and load distribution in different passage is different. The study indicates that there is a best wrap angle and the single-arc is not the best blade profile.