基于三元设计及数值试验轴流泵抗空化性能

为了提高轴流泵抗空化性能,采用泵的三元设计理论与数值试验相结合的方法,研究了汽蚀比转数为1 290的轴流泵抗空化性能.在相同的流量、扬程、转速等设计指标下,采用泵的三元设计理论对具有不同叶片数和过流通道形状的轴流泵模型分别进行了设计;并采用数值试验手段对所设计轴流泵模型性能进行计算和分析,得到了适合于该轴流泵的过流通道形状和最佳叶片数.运用相同的方法对不同叶片负载分布规律的轴流泵叶轮分别进行了设计,并采用数值试验手段计算了各水力模型的扬程、功率和效率特性曲线,对比和分析了不同负载分布规律对泵效率和抗空化性能的影响,得到了有利于轴流泵空化性能提高的负载分布规律.最后,根据数值计算结果,对如何有效提高轴流泵抗空化性能提出了建议:叶轮叶片后部重载光顺无阻塞的过流通道、适当增加叶片数将有利于轴流泵抗空化性能的提高.

3D design of axial-flow pump and numerical prediction of its cavitaion performance

The cavitiaton performance of an axial flow pump with suction specific speed of 1 290 was studied by using the 3D inverse design theory and computational fluid dynamics( CFD) technique to improve its cavitation behaviour. A few pump models with different meridional channels and numbers of blades were designed,respectively,at the same condition,i. e. the same flow rate,head,rotational speed; then a suitable meridional channel and a best number of blades were achieved with CFD method. Also,the other pump models with different blade loading profiles were designed by the 3D inverse method,their head,shaft-power and efficiency curves were predicted by CFD me-thod as well,effects of the blade loading on the pump efficiency and cavitation performance were compared and analyzed; eventually,a proper blade loading for an improved suction performance was achieved. A few suggestions were proposed for the pump to have better suction performance. For example,after-loaded blade loading profile,properly increased number of blades and a smooth meridional channel are helpful to improve cavitation perfroamnce of an axial-flow pump.