Centrifugal pump performance prediction and research status and prospects of what

The actual flow in a centrifugal pump is complicated and far from being recognized so far that pump design has so far remained in semi-theoretical and semi-empirical stages. Domestic development of pump products generally have to go through the design, trial production, testing, improvement process. Such a cumbersome process consumes a lot of time, manpower and financial resources. Accurately predicting the pump performance curve based on the geometric parameters of the overcurrent components such as the pump impeller and volute can greatly reduce the cost of model making, prototype and test and shorten the design and manufacturing cycle of the pump. The current pump performance prediction results can not fully meet the needs of engineering applications, so the pump performance prediction in-depth study has important theoretical significance and social and economic benefits.

Research status at home and abroad: For a long time, scholars at home and abroad have done a lot of research on the performance prediction of centrifugal pumps and made a lot of achievements. In summary, they mainly include flow field analysis, hydraulic loss and neural network.

Flow Field Analysis The essence of flow field analysis is to establish the relationship between the flow field characteristics inside the centrifugal pump and pump characteristics, is an important issue in the field of pump research. Mainly includes two aspects of the problem: First, to obtain the characteristics of the pump internal flow field; second is to establish the relationship between the pump and the internal flow field characteristics. At present, there are more researches on the former both at home and abroad, and have made a lot of research results, while the research on the latter is few and in the initial stage.

The numerical simulation of the flow field inside the centrifugal pump includes the simulation of the flow field in the pump impeller, the suction chamber and the pressurized water chamber. In order to ensure the accuracy of the performance prediction, a full three-dimensional numerical simulation is generally conducted. Because the flow in the pump is generally turbulent, and the numerical simulation of turbulence is a difficult point of CFD (Computational Fluid Dynamics), it is also a hot spot at the same time. Therefore, full three-dimensional numerical simulation of the flow field in the pump is also available Big difficulty. At present, there are three main methods of numerical simulation of turbulence: one is Direct Simulation (DNS). Due to the limitations of computer speed and capacity, this method is also applied less in engineering. Second, large eddy simulation (Large EddySimulation). This method decomposes the turbulent motion into a highly anisotropic large-scale vortex and a roughly isotropic small-scale vortex by some filtering method. The former is directly calculated by numerical solution of the differential equation, while the latter affects the former by approximate Simulation to deal with. As with direct simulation requires a relatively large computer capacity and very fast processor. The third is the Reynolds time average method, which is currently the main method used in fluid machinery. This method averages the NS equation over time, and solves the problem of the average weight of the cake, but requires the turbulence model to be used to close the system of equations. The K_e two-equation turbulence model is one of the most studied and widely used models because of its good accuracy and universality, and its calculated amount is not too large. Regardless of which method of calculation is used, all computations are done by the computer, including a series of processes such as modeling, network division, computation and flow field analysis. At present, many commercial softwares such as FLUNT, STARCD and FIDAP can perform 3D turbulence calculation and have certain accuracy.

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