| Speed limiting shut-off valve has many advantages,such as high sensitivity,fast and reliable switching,safe and convenient use and so on,so it is widely used in hydraulic system with safety requirements.At present,there are many kinds of speed limiting shut-off valves used in low-pressure and low-flow situations,such as hydraulic elevators,and these products are relatively mature.However,there are only a few kinds of speed limiting shut-off valve products can be used in high pressure and large flow field,such as tension compensation system,and most of the advanced products are monopolized by a few foreign hydraulic companies.Therefore,the study of speed limiting shut-off valve which is used in tension compensation system and other large marine engineering equipment has an extremely important significance.In order to meet the demand of the tension compensation system,this paper carries out the structure design,simulation analysis and experimental research of the speed limiting shut-off valve for tension compensation system.The main contents are as follows:The first part mainly analyzes and summarizes the research status of the speed limiting shut-off valve at home and abroad.First of all,the paper analyzes and studies the typical application of the speed limiting shut-off valve.Secondly,the existing theory,experimental research methods and research results of speed limiting shut-off valve are analyzed and summarized.Finally,according to the previous analysis and research,three key technical problems to be solved in the design of speed limiting shut-off valve for tension compensation system are proposed.The second part mainly studies the structure design of the speed limiting shut-off valve for tension compensation system.First of all,the working mechanism of the tension compensation system and the speed limiting shut-off valve are studied,and the performance requirements of the tension compensation system for the speed limiting shut-off valve are proposed.Secondly,a new speed limiting shut-off valve structure which has before and after orifice and tapered flow channel is designed.Finally,according to the designing formula of flow control valve,complete the structural parameters calculation of the new speed limiting shut-off valve.The third part mainly carries out the simulation research on the static performance of the speed limiting shut-off valve for tension compensation system.First of all,the static and dynamic performance of one existing typical structure speed limiting shut-off valve is simulated and compared with the existing results to verify the correctness of the simulation methods.Afterwards,the three-dimensional geometric model of the speed limiting shut-off valve is established by UG software and simulated by FLUENT software.The analysis results shows that the tapered flow path structure can reduce the velocity vortex of the flow path in the valve and achieve better static performance.The fourth part mainly carries on the simulation analysis of the dynamic performance of the speed limiting shut-off valve for tension compensation system.Firstly,the mathematical model of the tension compensation system including speed limiting shut-off valve is established.Secondly,bases on the mathematical model,the dynamic simulation analysis model of the tension compensation system is established,the influence trend and extent of key structural parameters(such as the diameter of the orifice,the spring stiffness,the pre-pressure of the spring,the quality of the valve spool and so on),and the mass of cylinder on the system response is analyzed.In the fifth part,the experimental research on the sample of the speed limiting shut-off valve is carried out.First of all,a new experimental method is proposed which is to use the active cylinder drive the passive cylinder to produce the large flow to close the speed limiting shut-off valve.Secondly,the signal acquisition system is composed by pressure sensor,pull line displacement sensor and PC;the pressure sensor and PC are used to collect the pressure signal,the pull line displacement sensor and PC are used to collect the displacements of valve spool and hydraulic cylinder.Finally,on the constructed test system,the dynamic performance(such as cutting time,cutting flow,etc.)of the speed limiting shut-off valve in the original configuration is experimentally studied,and the dynamic performance of the speed limiting shut-off valve under different key structural parameters(such as different size of before and after orifice,different quality of valve spool,different pre-pressure of spring and so on)is also experimentally studied.The experiment results are consistent with the conclusions of the simulation analysis on the main dynamic performance of the speed limiting shut-off valve(such as cutting time),while the influence trend and degree of each parameter on the dynamic performance of the speed limiting shut-off valve are also consistent with the simulation results,so as to verify the correctness of the simulation analysis results.The sixth part summarizes the main research work and achievements of the full text,and prospects the future research direction. |
PDF Full Text Request