Simulation On Dynamic Characteristics And Flow Fields Of Electromagnetic Unloading Valve

Along with the rapid development of mining mechanization, the demand for pressure control and overload protection for emulsion pump becomes more and more high. Because of some shortage of traditional unloading valve in pump station, it cannot meet the requirements. The difficult problems were solved by applying the electromagnetic unloading valve. The electromagnetic unloading valve was selected as the key parts for pressure control and overload protection in emulsion pump, the research of electromagnetic unloading valve has already been paid enough attention.In order to meet the characteristics of sensitivity, stability and big flow rate of electromagnetic unloading valve. The structure and working principle of the electromagnetic unloading valve were analyzed and the body cavity flow characteristics equation, kinematics differential equation were described by using fluid mechanics and fluid dynamic, lastly the dynamic mathematical model of the valve was established, the key size parameters of unloading valve was calculated.This paper used AMESim code to establish the simulation model of electromagnetic unloading valve and analyzed dynamic characteristics influenced by the different parameters of the unloading valve. The results showed that the bigger flow rate of the main valve was, the smaller core damping hole diameter of the main valve was; The pilot valve pressure overshoot was higher and the number of the valve oscillation was more greater when the main valve core on cavity volume is more smaller; The bigger cavity volume of the main valve was, the earlier the pilot valve open time is and lower pressure overshoot of the pilot valve was; The results showed that with the increase of the spring stiffness, the number of the oscillation of the valve core and the overshoots of the displacement decreased; To compared with unloading valve controlled by electromagnetic and mechanical, when unloading valve controlled by electromagnetic, the pressure fluctuation of main valve was lower, the open time of the main valve was earlier, the steady unloading time was shorter.The paper used CFD code FLUENT to establish the2d flow field simulation model of main valve and the unloading pilot valve. The simulation results showed that the high pressure fluid speed mutation and pressure drop is the largest when high pressure fluid flow through the throttle mouth place. The appearance of cavitations and eddy was easily to observe at the place of throttling mouth area. The paper optimized and improved the structure of main valve, then made the contrasts of the pressure, velocity distribution and whirlpool intensity to the original structure, results showed that the improved valve can get better flow field characteristics. The research work of electromagnetic unloading valve can provide a theoretical reference value for its structure design and optimization design, it also has a certain practical meaning to ensure the stability and reliability of the emulsion pump.