Simulation Of The Flow Field Analysis And The Dynamic Characteristics Of The Manual Pilot Valve

Hydraulic support is the support equipment of fully mechanized coal face. Its main role is to support coal seam roof, maintain safe operating space and elapse the face harvesting equipment. It is indispensable for automation of coal mining equipment. Manual pilot valve control system is one of its core elements. For any mechanized mining face bad environment, manual pilot valve gradually widely used due to its good sealing ability over current, fast response and anti-pollution ability.However, there are many problems in the pilot valve control system, such as the complex structure of the pilot valve and the main control valve pipeline. When oil flows through the pipeline, due to the sudden expansion of the flow channel, contraction, these complex areas will produce reflux, whirlpool, vibration and other phenomena. These phenomena will result in the loss of energy of the fluid, so that the emulsifiable liquid temperature will elevate the cavitation, vibration and noise of the valve will exacerbate. This will reduce the life of the valve. How to reduce and eliminate these effects and to improve the capacity of over flow valve and to reduce the pressure loss of the valve without increasing the dimensions of the valve is the main problem of the various manufacturers and also university research direction.According to the method of the research point of view, the computer simulation is an efficient, time-saving research methods. In this paper, the pilot valve and the main valve of the system and its internal flow field simulation by AMESim multi-disciplinary field of complex systems modeling and simulation and Fluent fluid dynamics analysis software.Manual pilot control system simulation model is built through the AMESim software platform. The simulation has been conducted from several parameters affect the manual pilot valve, including the pilot valve orifice, the orifice of the main spool and the main spool cone angle of the main valve. The results show that:As the pilot valve and main spool orifice with the opening degree increases, the response time of the spool is becoming shorter and shorter, the speed of movement of the spool will accelerate and the spool oscillation amplitude is increasing. This will aggravate the spool collision. When the main spool taper angle is15°, the main spool displacement is the smallest,the overcurrent area is the smallest and the flow rate is minimum. With the spool cone angle increases, collision of the valve body decreases during closing.By using computational fluid dynamics software Fluent, manual pilot valve and main valve flow field simulation is conduct. Major analysis of area of prone vortex and cavitation of the pilot valve and main valve and obtain the figure of the pressure distribution of the flow field, velocity distribution and turbulent kinetic energy distribution. At the same time, different valve port opening and taper conditions of flow field is studied and the measures to solve these problems is pointed out. The result shows:As the pilot valve inlet and outlet openings degree increases, the oil flow rate decreases, the size and strength of the whirlpool area decreases and cavitation increases. With the main spool opening gradually increase, the flow rate of the fluid increases, the spool low pressure area and the negative pressure area become smaller, loss of kinetic energy become lower. This will lead to small chance of the formation of vibration, whirlpool zone and noise. With main spool imports cone angle increases, the smaller the impact and abrasion of the oil on the spool, the slower the speed of the fluid, the bigger the area of low pressure and negative pressure area and it is more easy to form cavitation. The measures can help to reduce the possibility of cavitation generated theoretically. The simulation of the flow field results contribute to establish the exact parameters of the manual pilot valve and main valve model.This paper has some reference value for the design and optimization of the manual pilot valve structure and a certain practical significance to improve the efficiency of coal production.