Multiple parameters and multiple conditions optimization based on two steps strategy for an axial flow pump

Axial flow pump with high specific speed and large flow rate has been widely used for ship propulsion, water transfer and pump station, and now it meets the demand to work in a wide operation region with high performance. In the present work, a multiple parameters and multiple conditions optimization system based on two steps strategy is proposed and established for an axial pump. The multiple parameters and multiple conditions optimization system includes the controllable blade load design method, Kriging surrogate model, numerical simulation, parameter sensitively analysis method and multiple islands genetic algorithm. A two steps strategy is proposed for multiple conditions optimization. In this optimization strategy, the first step is to optimize the pump performance under the design condition, and the second step is to optimize the pump performance under other multiple operation conditions. In application of the multiple parameters and multiple conditions optimization for an axial pump, eight parameters are as follows: two cascade solidity parameters, two blade load parameters, two blade angle parameters, blade number and axial length. At design condition of 70 kg/s, the efficiencies of baseline pump and optimal pump are 84.249% and 85.419%, respectively, improving by 1.170%. For the multiple conditions optimization, the average efficiency of optimal pump in flow rate range of 30 kg/s to 100 kg/s is 2.562% higher than that of baseline pump. In comparison of baseline pump, the backflow of optimal pump near the shroud is obviously reduced, and the turbulent kinetic energy of optimal pump is greatly improved.