介质黏度对泵作透平特性的影响

Influence of medium viscosity on the performance of pump as turbine

为了明确介质黏度对泵作液力透平特性的影响规律,在实验验证数值计算方法可靠性的基础上,应用ANSYS软件对输运运动黏度分别为0.893、48.48和90.00 mm 2/s的3种介质的液力透平进行了数值模拟。结果表明,透平的外特性曲线趋势基本一致,随着介质黏度的增大,透平的水力效率下降,可回收压头增大,输出功率减小;叶轮叶片静压分布趋势基本一致,静压值随介质黏度的增大而减小;介质黏度对透平径向力的大小和方向影响较大;随介质黏度的增大,最优工况下湍流动能较高值分布区域由导叶-叶轮的动静耦合面向叶轮流道扩散;最优工况下透平内介质速度分布差异不大。研究结果能够为泵作透平在不同黏度介质下运行时的性能预测提供部分参考。

In order to clarify the effect of medium viscosity on the performance of pump as hydraulic turbine,based on the reliability of numerical calculation method verified by experiment,the numerical simulation of the hydraulic turbine with viscosity of 0.893,48.48 and 90.00mm 2/s was carried out by using ANSYS software.The results show that the trend of the external characteristic curve of the turbine is basically the same,with the increase of medium viscosity,the hydraulic efficiency of the turbine decreases,the recoverable head is increased,the output power decreases.The static pressure distribution trend of impeller blades is basically the same,and the static pressure value decreases with the increase of medium viscosity.The viscosity of the medium has a great influence on the magnitude and direction of the radial force of the turbine.With the increase of medium viscosity,the region of higher Turbulent Kinetic Energy distribution under the optimal condition is diffused from the dynamic and static coupling of impeller to the channel of impeller.Under the optimal condition,the distribution of medium velocity in the turbine has little difference.The research results can provide some references for the performance prediction of hydraulic turbine under different viscosity.