启动瞬态过程混流泵空化湍流结构演化机理OA

To reveal the transient evolution mechanism of cavitation structures in a mixed-flow pump during the startup process under strongly induced cavitation conditions,experimental investigations on cavitation turbulent structures were conducted during the rapid startup of a mixed-flow pump at an initial inlet vacuum degree of-30 kPa.High-speed photography,Voronoi cavitation structure identification,and grayscale quantitative analysis methods were employed to obtain the spatiotemporal evolution characteristics of the cavitation flow field inside the mixed-flow pump impeller during the 1 s startup process.The results indicate that under the 1 s rapid startup condition,the low-pressure region inside the impeller forms drastically within a short time,inducing synchronous cavitation excitation and rapid development into large-scale cavitation clouds,exhibiting transient characteristics of concentrated burst and intense collapse.The cavitation cloud covers multiple flow passages within an extremely short time and undergoes violent collapse,with its evolution process experiencing stages of inception,growth,collapse,and restructuring.Grayscale analysis shows that the cavitation intensity reaches its peak at approximately 0.60T,but significantly weakens as the impeller acceleration is completed.The research findings reveal the spatiotemporal organization laws of cavitation structures during the rapid startup of mixed-flow pumps,providing references for optimizing pump start-stop control strategies,mitigating transient cavitation impacts,and improving unsteady cavitation prediction models.