| Miniature water-jet propulsion pump is a device arranged on the tail wing of underwater glider to provide auxiliary thrust for it.As the core power component in the underwater glider,it is also the main energy consuming component,it relies on a built-in battery or fuel to provide energy.While the energy consumption and vibration of the water jet propulsion pump will have a significant impact on the duration and concealment of the mainframe.Therefore,the research on the hydraulic performance optimization and the operation stability of the miniature water-jet propulsion pump is of great significance to the national defense infrastructure construction in China.In this paper,the miniature water-jet propulsion pump is studied by means of theoretical analysis,numerical simulation and model test.The hydraulic model of different impeller is obtained by adjusting the structure of impeller blade airfoil,appropriate grid number was selected through grid independence analysis,steady and unsteady state numerical calculation of pump was carried out.And also put the water-jet propulsion pump into a tank to solve the open water operating condition.The hydraulic performance and internal flow state of different schemes,the pressure pulsation characteristics in the impeller,and the relationship between nozzle diameter and the open operating condition were both studied.In addition,the hydraulic performance test scheme suitable for the miniature water-jet propulsion pump is designed in view of it's low head characteristics and the model test was carried out.Based on the above work content,the following conclusions are obtained:(1)When the ratio of the distance between airfoil's maximum thickness position to the front edge and the chord length is 0.8,the jet pump has a broad high efficiency area and better hydraulic performance.When the airfoil's maximum thickness position is closest to the rear edge,the blade load near the blade exit edge is increased.(2)The pressure pulsation at the monitoring point in the impeller is closely related to the structure of the airfoil.The pressure fluctuation of monitoring point at the impeller inlet is far greater than that of the blade surface and the impeller outlet.When the airfoil's maximum thickness position is close to the front and rear edges,the main frequency amplitude of the monitoring point at impeller inlet is reduced.(3)Water-jet pump is inclined to large flow condition during open operation,changing the nozzle diameter can effectively adjust the open operatingcondition of the jet pump.When the nozzle diameter is 76 mm,the actual operating conditions of the jet pump are well matched with the design conditions.(4)By comparing and analyzing the experimental data and simulation results of different schemes,it is found that the two are in good agreement,which verifies the feasibility of the numerical simulation method and the test plan.The above research methods and the calculation results can be used for reference for the research on the optimization of the performance of the miniature water-jet propulsion pump and the solution of the basic problems in the partial operating conditions. |
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