| Hydraulic support is the key equipment of the synthetical mechanized coal mining, and in hydraulic support system, hydraulic operated check valve is one of crucial hydraulic components. Its performance affects the reliability and security of entire workplace directly. In this paper, the primary factors that affecting the hydraulic operated check valve are determined through the unloading dynamic simulation analysis and the numerical simulation of the flow field of hydraulic operated check valve in hydraulic support system, which has provided the basis for the later to the valve design optimized and performance enhanced .The simulation model of hydraulic operated check valve in hydraulic support unloading system is built and its dynamic characteristics are simulated using AMESim simulation software. The displacement curve of spool and the pressure curve and flow rate curve of valve port A are obtained. The simulation result shows the spool vibration and instantaneous pressure impact phenomenon are emerging during hydraulic operated check valve unloading. The simulation results of several diameters of the pilot valve port K are compared, and the spool vibration and impact pressure can be reduced by reducing the diameter of the pilot valve port K. Carries on the research work has offered the reference to reasonably design and optimize the structure of hydraulic operated check valve.The 2-D and 3-D geometrical model of hydraulic operated check valve is built by using AutoCAD and UG software, according to its actual structure and parameters as well as feasibility of computational mathematical model. The models are transformed and imported into GAMBIT software, which is the preprocessor of FLUENT to generate mesh. Both the flow field of model are simulated in FLUENT. The pressure distribution contour,the velocity vector distribution and the pathlines are obtained . With the same opening and different pressure difference and same pressure difference and different opening the flow flied is simulated, influencing factors which influenced the pressure distribution and velocity distribution are founded. Adopting the cavitation model to simulate, the volume fraction of vaporization water is obtained. The total force and the static fluid force acting on the spool are carried on through the theoretical analysis and computation. The simulation result and the theory result arecompared, which has confirmed the simulation result accuracy.The flow field analysis result manifests that, the speed of the orifice is influenced by the opening and the pressure difference. The larger the opening and the pressure difference are, the higher the top speed of the orifice is. Besides, the pressure is influenced by the opening and the pressure difference. The larger the opening and the pressure difference are, the lower the pressure of the orifice is. It is easiest to bring the cavition in the area that the pressure is lower than atmospheric pressure. When sectional area suddenly changed, mainstream is separated from wall, the eddy current area is generated in these places. When the opening is the same, the eddy current area is inflenced by the pressure difference. The larger the pressure difference is, the larger the eddy current area is. By contraries, the eddy current area is smaller; When the pressure difference is the same, the eddy current area is influenced by the opening, the larger the opening is, the smaller the eddy current area is. By contraries the eddy current area is larger. When the opening is the same, the more rate of flow is, the bigger in the value the static fluid force is; when the pressure difference is the same, the static fluid force increases along with the opening increasing, which is consistent with theory result.The study for the valve has offered the significant reference to design and optimize the valve structure. On the other hand, it also has a certain practical meaning to ensure the reliable work of hydraulic support system and the safe and efficient production of mine. |
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