空化条件下轴流泵叶轮静应力特性

空化特性和应力特性是轴流泵稳定运行的有力保障，研究空化条件下的应力特征具有重要工程意义。以轴流泵为研究对象，通过顺序流固耦合方法，将该轴流泵内部稳态空化流动的CFD分析结果作为主要力学边界条件，采用有限元方法，对未发生空化、空化初生和空化严重情况下的叶轮应力特性进行了分析。结果表明，轴流泵叶轮最大等效应力均发生在叶片靠近出口边的叶片根部位置；未发生空化和空化初生情况下，应力分布基本一致，最大等效应力值约36 MPa，当空化严重时，高应力区域较前两种情况缩小。取不同截面对叶片内部应力分布进行分析，发现空化严重时，压力面区域根部两端存在高应力区域，向叶片中部递减；而吸力面则仅在出口边一侧存在高应力区域。叶片压力面根部交线上应力分布随空化发生、发展分布趋势基本相似，但是吸力面根部交线上分布将由近似直线分布变为抛物线分布。 

Stress Characteristics of Axial Flow Pump Impeller under Cavitation Conditions

Cavitation characteristics and stress characteristics are powerful guarantee for stable operation of axial flow pump.It is of great engineering significance to study stress characteristics under cavitation conditions.Taking axial flow pump as research object，through sequential fluid solid coupling method，CFD analysis results of steady cavitation flow in axial flow pump were taken as main mechanical boundary conditions and finite element method was adopted，stress characteristics of impeller under cavitation，cavitation initial cavitation and severe cavitation were analyzed.Results showed that maximum equivalent stress of axial flow pump impeller occurred at blade root near outlet edge.Without cavitation and cavitation initiation，stress distribution was basically the same.Maximum equivalent stress was about 36 MPa.When cavitation was serious，high stress region was smaller than the first two cases.Stress distribution in the blade was analyzed by taking different sections.It was found that there was a high stress area at two ends of pressure surface area and it decreased to middle of blade when cavitation was serious，and suction surface only has a high stress area on side of exit side.Distribution of stress along intersection of blade pressure surface root was similar to that of cavitation，but distribution on intersection of suction surface root would change from approximate linear distribution to parabolic distribution.