不同级数深井离心泵性能的数值模拟与试验

选取250QJ80型深井离心泵作为研究对象,借助数值模拟和试验研究的方法,研究不同级数时深井泵性能的变化规律,并通过分析内部流场探究不同级数深井离心泵性能变化规律的本质原因.采用ANSYS-CFX 17.0软件对该深井离心泵模型在单级、两级以及三级时的性能分别进行了数值预测.对3组模型分别进行计算域建模,结构化网格划分,进而基于标准k-ε湍流模型和标准壁面函数进行多工况数值模拟,获得级数不同时深井离心泵的性能预测值,并将数值预测结果与试验结果进行对比分析.结果表明:深井离心泵级数的变化并不会对某一特定级数的性能造成影响,两级与三级离心泵首级扬程与效率高于其后各级,其后各级的扬程与效率差异不大.造成这些相似性与差异性的主要原因是:深井泵首级叶轮进口处的介质为无预旋入流,而当级数大于等于2级时,其后各级叶轮进口处的介质均存在一定的旋转分量.

Numerical simulation and test of performance of deep-well centrifugal pumps with different stages

A deep-well centrifugal pump of type 250QJ80 was chosen to be study model and features of the pump performance at different numbers of stages were explored numerically and experimentally, further the root causes for these features were clarified in terms of analysis of internal flow field in the pump. In the paper, software ANSYS-CFX 17.0 was used to carry out numerical predictions on the pump performance based on three pump models with single stage, two stages and three stages, respectively. The computational domain of three models has experienced geometrical modelling and structured-mesh creation, then the water flow field in these models were simulated under a few working conditions based on the standard k-ε turbulence model and standard wall function. The predicted performance of these models was obtained, compared and analyzed against the corresponding experimental data. The results show that the change in pump stages doesn′t affect the performance of the pump with a specific number of stages. However, the head and efficiency of the first stage are higher than those of the se-cond or third stages, while the head and efficiency of the second stage doesn′t differ obviously from the third stage. The main reason for this similarity and difference in the head and efficiency is that the impeller of the first stage is without any pre-swirl, while the impellers of the rest stages are subject to a certain amount of pre-swirl.