Research On The Multi-objective Optimization Of The Hydraulic Model Of The Centrifugal Pump

In allusion to the multi-objective optimization of the centrifugal pump at present, a new multi-objective optimization method that combines the objectives that include the energy loss, the NPSH_r and the stability of the pump with the super-transitive approximate method is first proposed. The main contents are that the super-transitive approximate method is used to evaluate the important degree of the target functions and confirm the weight of the target functions and consequently the optimal parameters are obtained according to the important degree of the target functions, thus the paper will carry out the research in such aspects as up-building the mathematical model, writing optimization program, up-building three dimensional model, creating grid and numerical simulation of the flow field.First of all, according to important degree of the target functions, the weight of the target functions is confirmed. The target functions are unified by the linear weighted method and the right constraint conditions are confirmed. Then the full mathematical model is set up. The composite form method of the direct searching optimization is used to calculate the mathematical model by the FORTRAN language and finally the optimal parameters in the right constraint conditions are obtained.Secondly, the three dimensional entities of the impeller and volute chamber both before optimization and behind are plotted in the pro/engineer wildfire2.0.The grid of the flow field is created and the right boundary types and continuum types are presented in the GAMBIT. The flow field is simulated in the FLUENT and the standard k-εturbulence model and SIMPLE method were applied. The numerical results were obtained.Finally, the velocity vector and pressure fields both before optimization and behind were obtained.It was founded that the pressure value in the facing of a quilt of the vanes anear the entrance of the flow path behind optimization was less than before. The axial whirlpool was eliminated almost.Thus,the validity and the effect of the new multi-objective optimization method are proved.