| Rock burst is one of the most serious natural disasters in coal mines and rock engineering in the world,and the anti-impact hydraulic support equipment can play an effective role.In order to test its related performance,a 6500 k N static-dynamic combined load hydraulic impact testing machine was developed.In the process of development,the problem of super-large flow quick opening valve was found.In this paper,theoretical analysis and experimental research are carried out to solve the problem of large flow and instantaneous opening of the spool.In this paper,a new type of structure of large flow quick opening valve and its structure and working principle are introduced,to theoretical calculation and design of key dimensions,and the valve core are calculated fluid power,set up the sealed case dynamic mathematical model of the open process and use the MATLAB/Simulink software simulation analysis was carried out on the seal open time properties of cases,Finally,the optimal design of the seal protective sleeve is completed.ANSYS/FLUENT software is used on the analysis of internal flow field in steady state is different under different import and export pressure differential valve core is the valve core of the internal flow field axis plane velocity contours,and draw the flow velocity and flow chart,find the proportional relationship between the velocity and the valve core is,the analysis found that the flow chart is turbulent flow phenomenon and the jet action of the cause,And there is a proportional relationship between the flow and the spool opening degree;By analyzing the influence of steady fluid force on the spool opening,it is found that with the increase of the spool opening degree,the steady fluid force changes from impeding the spool opening degree to promoting the spool opening degree,and the critical spool opening degree is obtained.And the spool is optimized to advance the critical spool opening degree and make the spool open earlier.Transient analysis of the flow field in the valve was carried out by using the dynamic grid technology and the UDF function written for the valve core and the pressure difference between inlet and outlet.The flow field in the valve core was simulated,and the velocity neograms and flow charts of the axial section of the valve core at some moments were obtained.It is found that the maximum instantaneous flow can reach 133920L/min by drawing the transient flow curve.Analysis of the flow curve,found that the spool at the initial time of the flow showed a downward trend,analysis of the flow diagram found that the spool is due to the small opening caused by the turbulence phenomenon;The influence of transient fluid power on the opening of the spool is analyzed,and it is found that the fluid power of the spool is large at the initial time,which leads to the difficulty of opening the spool,which is also one of the reasons for the decrease of the flow at the initial time.AMESim software was used to build a simulation model of the loading system.The dynamic analysis of the loading system was carried out,and the dynamic opening response characteristic curve of the spool was obtained.It was found that the opening time of the spool and reach the maximum instantaneous flow was about 22 ms,the maximum instantaneous flow is136823L/min,and the impact velocity is 12.84m/s.The impact force and time curves of the precrimped energy absorber and the energy absorber and anti-impact hydraulic column in the opening stage of the spool were obtained by carrying out the relevant loading impact tests.The instantaneous flow was calculated and found to meet the design requirements,which verified the correctness of the simulation analysis of the transient flow field and the rationality of the structural design.There are 67 figures,7 tables and 66 references in this paper. |
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