Optimization of water-jet pump based on the coupling of multi-parameter and multi-objective genetic algorithms

As the core component of water-jet propulsion system, water-jet pump, directly affects the ship’s propulsion performance. Three-dimensional (3D) inverse design can obtain higher hydraulic performance of pump impeller and diffuser. It is an efficient and feasible way to coupling optimization based on multi-parameter, multi-objective, and optimization algorithms, and parameterizing the impellers and diffuser geometry based on the 3D model designed by 3D inverse design method. In this paper, the water-jet propulsion pump is selected as the research object. Based on the design methodology of the hydraulic model for the water-jet pump, traditional axial flow blade design methods, modern three-dimensional blade design theory, and parametric 3D inverse design methods are employed to develop an optimization strategy for the water-jet pump impeller using a multi-parameter, multi-objective genetic algorithm. The impeller is optimized using this strategy, and the performance of the model before and after optimization is compared through simulation and experimental results. Under the design conditions, the optimized pump efficiency reaches 89.28%, which is 1.24% higher than the original hydraulic model. The optimized pump head is 13.51 m, which is 0.39 m more than the original hydraulic model. The numerical calculation result is 1.88% higher than the test result, the test measured efficiency is 87.1%, and the numerical calculation result is 2.5% higher than the test result. The experimentally measured critical cavitation margin was 7.58 m, and the numerically calculated critical cavitation margin was 7.36 m, both of which indicate a high critical cavitation margin and strong cavitation resistance.