| This paper is based on a project of underwater automata,the sealing and leading device of the underwater automata are taken as the research object.According to the characteristics of the underwater working condition,the related researches are carried out in the aspects of the dynamic characteristics of the launching process,the action characteristics of the gas-liquid two-phase flow at the muzzle,the sealing and movement characteristics of the sealing device,the cavitation pressure reducing action characteristics of the leading device and the dynamic characteristics of the underwater automata.Through the research,the influence of opening and closing time,initial pressure in bore and initial medium pressure on launching process,sealing performance and motion characteristics of mechanism are found,the structure of sealing device is determined,and the scheme of improving sealing and launching performance by using leading device is put forward,and the feasibility of the scheme is verified by analysis and experiment.Finally,the influence law of the sealing and leading device on the dynamic characteristics of the underwater automata is obtained,which provides some reference for the design of the underwater automata.The article is carried out from the following five aspects:1.In order to study the launching process dynamic characteristics of underwater automata,a mathematical model of launching process dynamic characteristics of underwater automata is established based on the classical theory of launching process dynamic characteristics.By solving the model,the launching process dynamic characteristics of underwater automata under various working conditions are obtained,and the influencing factors and laws are studied.2.Based on the study of the launching process dynamic characteristics,in order to determine the influence of the opening and closing time of the sealing device,the initial pressure in the bore and the initial medium pressure on the drainage and pressure relief,the two-phase flow theory is used to establish the flow field model of the bore,and the FVM is used to solve it.The development law of the bore flow field is obtained,and the appropriate opening and closing time is determined.3.According to the conclusion of the flow field analysis,the structural characteristics of the sealing device are determined,and the sealing and motion simulation model of the sealing device is established by using the FEM theory.The influence of the sealing preload and the initial medium pressure on the sealing performance and the movement of the device is studied.The sealing and dynamic characteristics of the sealing device in the sealing process are obtained by solving the model analysis.4.In order to achieve better sealing effect,a scheme of leading device is put forward,and the formation conditions and effects of cavitation and depressurization of leading device are studied.The flow field simulation model of single wing is established by using cavitation theory,and the flow field simulation is carried out to obtain an appropriate wing structure.On this basis,the overall structure of the leading device is determined and verified by simulation and test.The simulation results are in good agreement with the test results,which verifies the reliability of the calculation scheme and the feasibility of the leading device.5.The influence of sealing and leading device on the dynamic characteristics of the automata is studied.The mechanical model of the underwater automata with the seal leading device is established by using the bond space theory.The influence of the seal leading device on the key design parameters of the underwater automata,such as the launching speed and the output power of the motor,is obtained by solving and analyzing the model. |
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