| A small type centrifugal pump is regarded as investigate object in this paper, the transient characteristics of the centrifugal pump during rapid starting period and its numerical prediction method are studied accordmg as transient exterior characteristic and unsteady flow of centrifugal pump. According to the theoretical analysis on effect of impeller accelerating, the generalized equation of centrifugal pump is given to describe dynamic head, and the concept of unsteady head is brought forward.First, the flow mechanism of the centrifugal pump is studied from theory. The transient head of the centrifugal pump is converted into an average head and a pulse head brought by impeller accelerating.The test methods of rapid starting experiment are explained by introducing structure of testing bed, design of testing instrument system and data acquire system; and data revising methods and data processing methods are introduced respectively. The basal transient characteristics, starting performance under various final rotational speeds and starting performance under various discharge valve settings are analyzed by various experiment studies of the centrifugal pump.At the same time, experiments are done on the big centrifugal pump. The experimental results provide the theoretical foundation and indicate that the big centrifugal pump used in Air Turbine Pump Ejection System is very adapted.The simulation methods of unsteady flow in pump are introduced. Control equations, which calculate accelerating effect adequately, are advanced to describe unsteady pump flow induced by impeller accelerating. The influence to interior flow of pump by impeller accelerating is analyzed according to comparison of unsteady results and steady results.The transient exterior characteristics of small type centrifugal pump during rapid starting period are provided by various experiments in this paper. The resolution model of transient flow under impeller speed rapid change has been established, which not... |
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