CFD Analysis And Dynamic Characteristic Optimization Of Safety Valve Of Hydraulic Support

The hydraulic pressure of safety valve is the key to the hydraulic pressure of hydraulic support in coal mine,and it is an important part of promoting green mining in coal mine.However,the physical and chemical characteristics of high vaporization pressure of water medium make the throttle of hydraulic components prone to cavitation damage,especially under the condition of high pressure and large flow of coal mine equipment,cavitation is more obvious,which seriously restricts the development of water hydraulic technology in coal mine equipment.And if the pressure drop at the orifice is too large,it will cause pressure fluctuation,vibration and noise,and affect the dynamic performance.In this paper,the safety valve of high pressure and large flow hydraulic support is taken as the research object,and water is taken as the working medium.In order to solve the cavitation problem,the influence of different structural parameters on the cavitation distribution of the valve cavity is studied from the structural optimization.At the same time,based on the results of cavitation research,the influence of different parameters on the valve stability is analyzed.The main research contents are as follows:(1)According to the structural characteristics of the traditional hydraulic support safety valve,the key geometric dimensions are calculated,the multi-phase flow model of the valve cavity is constructed,and the grid independence is verified by fluent.When the number of grids reaches 170000,the calculation results are basically unchanged;the distribution of the pressure,velocity,gas phase and turbulent kinetic energy of the valve cavity is analyzed.From the point of view of partial pressure,the double valve port structure is designed,simulated under the same conditions,and compared with the traditional safety valve,it is found that the negative pressure area of the valve cavity is reduced,and the maximum gas phase volume fraction is reduced.The subsequent research based on the double valve port structure is more reasonable.(2)Based on the mechanism of cavitation,the effects of the number of valve ports,the distance between the holes and the diameter of the holes on the pressure and gas distribution in the valve cavity were studied.With the increase of the number and diameter of the valve port,the maximum volume fraction of the gas phase in the valve chamber decreases,and the pressure distribution is more uniform;when the hole spacing increases,the maximum volume fraction of the gas phase in the valve chamber decreases first and then increases.After optimizing the parameters,the maximum gas volume fraction is 19.4%lower than that of the traditional safety valve.At the same time,the influence of the start-up sequence of double row valves on cavitation was studied.When the double row valve port is started synchronously,the range and time of cavitation in the moving process of the valve core are the largest and the longest;when the valve port 1 is opened first,the range of cavitation is reduced;when the valve port 2 is opened first,the range of cavitation in the valve cavity is further reduced,and the cavitation resistance is the best.(3)Based on the structural characteristics of the double row valve port and parallel double spring of the safety valve studied,the acting area and spring stiffness are treated equivalently.AMESim is applied to the dynamic analysis of the safety valve studied,and the effects of the equivalent mass of valve core and its accessories,the equivalent stiffness of spring,the number of valve ports,the diameter of valve port and the overlap of valve port on the pressure and displacement of valve core are studied.Increasing the spring equivalent stiffness,reducing the equivalent mass and valve port overlap can reduce the valve port pressure and improve the valve stability.When the number of valve ports is 16 and the diameter of valve port is 1.4mm,the dynamic performance and anti cavitation performance of the valve are optimal.At the same time,the influence of interaction among parameters is studied,and the optimal combination of parameters is obtained.Fig[56]table[8]reference[101]...