Research on hydraulic optimization design method of water-jet propulsion pump considering hump index

In order to improve the efficiency of water-jet pump and reduce or eliminate the hump phenomenon, it is necessary to optimize the impeller design. In this paper, the optimization of water-jet propulsion pump is studied by combining numerical simulation and experiment. The orthogonal optimization design scheme is established. Based on the numerical simulation method, the hydraulic performance indexes such as energy coefficient, torque coefficient and efficiency of the design points of different design schemes are obtained. The final optimization design is completed by further optimizing the profile and spatial position of the optimal efficiency factor level combination A2B1C1D1 at different spanwise heights. The efficiency of the optimized model pump is 81.1%, which is 3.7% higher than the original model. The efficiency of the optimized impeller is 94.7%, which is 1.9% higher than the original model. The internal pressure distribution and streamline distribution of the optimized impeller are more uniform, and the difference between different flow channels is smaller. Then, based on the results of numerical simulation by CFX, using Python and LabVIEW programming software, a pump flow head curve fitting and hump judgment program is developed, which can realize the function of curve fitting of flow head, giving the position of trough and peak, and calculating the value of hump climbing coefficient Chump. The influence of different blade structure parameters on the hydraulic performance and energy characteristic curve hump of the water-jet pump is analyzed, and the optimization design of the high-performance water-jet pump considering the hump index is completed.In summary, this method is not only applicable to the hydraulic optimization of the water-jet propulsion pump, but also the research results can provide theoretical basis and technical support for the high-performance and low-vibration design of the water-jet propulsion pump.