Nozzle Jet Thrust Analysis And Its Vector Adjustment Test Study

Underwater robots are important tools for underwater exploration,search,salvage and other underwater operations.Improving their handling performance and motion control performance have become the focus of underwater robot technology.The water jet propulsion has the advantages of low noise,simple transmission structure and vector adjustment easily,the advantages make this new type of propulsion have broad application prospects in the field of marine engineering.In this paper,medium and high pressure jet propulsion of nozzles and its vector adjustment technology are studied,the influence of nozzles with different structures and parameters on the jet thrust magnitude are analyzed.The hydraulic artificial muscle is used as the nozzle vector adjustment driver.The nozzle two-degree-of-freedom vector adjustment mechanism is designed and developed to drive the nozzle jet deflection,and then the vector advancement of the nozzle jet vector adjustment prototype is realized.The main contents of this paper are as follows:(1)Introduced the research background and significance,comprehensively analyzed the development trend of water jet propulsion technology,the research status of reaction thrust of nozzle jet and vector adjustment,and put forward the main research contents of the paper.(2)The basic principle of water jet propulsion technology is introduced.The three-dimensional nozzle submerged jet flow field is modeled and simulated by Fluent software.The momentum integral method is used to calculate the reaction thrust of the nozzle submerged jet,and the jet flow field of different structure nozzles are compared and analyzed.(3)In order to measure the nozzle reaction thrust of different structures and parameters in the submerged state,and fully embody the effect of submerged environmental fluids,a nozzle submerged jet column reaction thrust test system is built in Dalian Maritime University rescue and salvage engineering pool.The nozzles with different structures and parameters are processed.The reaction thrust of the nozzles are measured under different inlet pressure.By comparing the flow field simulation results and the test results,the influencing factors of the nozzle reaction thrust are analyzed,and the methods of improving the nozzle reaction thrust are proposed.(4)The nozzle two-degree-of-freedom vector adjustment test system is designed and built.The static characteristics of the independent degree of freedom nozzle vector adjustment are studied.The nozzle jet and vector adjustment system are jointly adjusted,and the self-propulsion test is carried out in the pool.(5)Finally,the content of this paper is summarized,and the future research work is prospected.