隔舌安放角对离心泵性能影响的分析

Impact of Placed Angle of Volute Tongue on Centrifugal Pump Performance

对比转数为195的单级双吸式离心泵,分别建立3个不同隔舌安放角时的蜗壳、叶轮及吸入室的三维模型,以这3种不同隔舌安放角的离心泵模型为研究对象,基于FLUENT软件,建立相对坐标系下的时均连续方程及N-S方程,并采用标准k-ε方程湍流模型、非结构四面体网格和SIMPLE算法进行数值模拟,得到其流场分布,计算出模型进出口压力及流体对泵轴的力矩;在叶轮转速不变,进口速度变化的10个工况下,得出泵的流量-效率曲线。在此基础上,对比不同隔舌安放角时流场分布和特性曲线,发现隔舌处压力、速度分布及特性曲线变化均与隔舌安放角大小有关,得出设计工况隔舌安放角在33°时水力损失较小,模型泵的效率最高。

The contrast for single-stage double-suction centrifugal pumps with rotation speed 195 ns was established for the tongue placed in three different angles of the volute, impeller and the suction chamber of the three-dimensional model. Taking the three different angles of the centrifugal pump placed in every model of the tongue as study objective, based on software FLUENT, the authors bulit time-averaged continuity equation and the N-S equations under relative coordinate system. The numerical simulation of flow field was conducted by using standard k-~ turbulence model equations, unstructured tetrahedral grids and SIMPLE algorithm. The the fluid pres- sure and the torque on the shaft in import and export ports were calculated ; the pump flow -efficiency curve was obtained for the same impeller speed and inlet velocity change within 10 conditions. On this basis, by comparing the different angles of every tongue placement and flow field characteristics, it was found that the pressure across the tongue and the change of velocity distribution curve are related to the size of placement angle for each tongue. Less hydraulic loss will attain under the design conditions at the tongue placed angle of 33° ,and the model of the pump had the highest efficiency.