Numerical Simulation Of Cavitating Flow In Axial-flow Pump

The cavitation phenomenon exists widely in the operation of hydraulic machinery,which is the key constraint to further improve the performance of hydraulic machinery. Theoccurrence of cavitation will decrease the performance of hydraulic machinery, causeadditional noise and vibration, and lead to cavitation erosion. The uncontrollable cavitationwill cause disastrous consequences. The study of cavitating flow characteristics in axial flowpump will contribute to a more in-depth understanding of the cavitation mechanism inhydraulic machinery, and provide theoretical support to control the degree of cavitation inengineering application effectively.The horizontal shaft axial-flow pump is adopted as the study object. The whole flowpassage in different inlet velocity conditions including rated condition and off ratingcondition has been simulated by using the CFD approach. Systematic study on thecharacteristics of steady and transient flow field has been done. The major works andachievements are as following.Detailed Analysis of the disadvantage of cavitation number and the basic equation ofpump cavitation in engineering applications and detailed descriptions about influence factorsof cavitation and has been given. Make a brief introduction of the cavitation types inhydraulic machinery.Build the numerical calculation model of whole passage field by discretizing thecomputational domain with multi-block structured grid. Summarize the meshing experienceon axial-flow pump blade flow field with structure grid. Make detailed descriptions onelaborate impeller cyclical approach, boundary layer meshing, and blade trailing edgeencryption mesh optimization method.According to comparative analysis of calculation results of different turbulence modelsand velocity pressure coupling algorithm, the adaptive simulation model of cavitating flow inaxial-flow pump was determined. Based on conformed method, the three-dimensional steadyand transient turbulent cavitating flow in different inlet velocity conditions including ratedcondition was simulated. The evolution law of cavitation location and degree of cavitation indifferent conditions was carried out. Systematic study on the frequency domaincharacteristics of pressure pulsation in transient flow field has been done.Research methods and achievements form this paper can be extended and applied onstudy of cavitating flow in other types of hydraulic machinery.