流固耦合作用对离心泵内外特性的影响

应用双向流固耦合方法对导叶式离心泵的外特性和内流场进行分析,研究流固耦合作用对外特性影响的内流机理。流场的定常数值模拟采用雷诺时均方法和标准k-ε湍流模型,非定常数值模拟采用大涡模拟方法,结构响应采用线性瞬态动力学方程。通过对流固耦合前后内部流场的对比,包括叶轮出口处的总压分布和相对速度分布,分析了流固耦合作用对外特性预测值影响的内流机理。同时,对叶轮出口处的压力脉动进行了分析。结果表明,流固耦合作用产生的叶轮变形,尤其是叶轮出口处的较大变形是导致离心泵外特性预测值变化的主要原因。考虑流固耦合作用后,叶轮出口处压力脉动周期性变化的总体趋势与非流固耦合结果基本一致,但振幅更大。考虑流固耦合作用后的最大压力脉动幅值提高了3.1%。研究结果为离心泵性能预测及流动诱导振动的研究提供参考。

Effect of fluid-structure interaction on internal and external characteristics of centrifugal pump

In order to study the inner flow mechanism of the fluid-structure interaction (FSI) effect on the external characteristics, the external characteristics and internal flow features of a diffuser pump were analyzed with the two-way flow solid coupling method. The steady flow field was based on Reynolds Averaged N-S equations with standard k-E turbulent model, the unsteady flow field was based on the large eddy simulation, and the structure response was based on elastic transient structural dynamic equation. Compared with the results without FSI, the total pressure and velocity distributions at the outlet of the impeller were analyzed. Inner flow mechanism for the effect of the FSI on prediction of the external characteristics was calculated. And the pressure fluctuations of the impeller at outlet were also analyzed. The results show that, the main reason for the variation of the external characteristics prediction based on the effect of the FSI is the deformation of the impeller, especially at the outlet of the impeller. Considering the effect of the FSI, the tendency of the pressure fluctuations is similar to the results without FSI, but the amplitude is larger. Maximum pressure pulse amplitude is improved by 3.1 percent. The results can provide reference for the research of performance prediction and flow induced vibration in centrifugal pump.