Study Of Flow Field And Sealing Performance For Clearance Seal In Reciprocation Motion

The impact cylinder is a key equipment of the mechanical rapping device, and its performance determines the operation of the entire system, and its sealing characteristics will determine the impact of the cylinder’s life and impact energy, Thereby increasing the sealing performance of improving the impact performance of the cylinder is of great significance.In this paper, the performance of the new seal structure between the piston and the cylinder of the impact cylinder, was numerical simulated and experimental studied. And the effects of sealing gap width, the seal gap differential pressure and reciprocating piston velocity on the gap sealing performance is studied.Firstly, the piston under relatively quiescent state, the mathematical model of the structure of the clearance seal between the piston and the cylinder is established, and the Fluent is adopted to study the he pressure distribution, velocity vector distribution and leakage in seal gap of gap under gap width of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, when the inlet operating pressure change from 0.3MPa to 0.5MPa, the linear regression analysis is used to obtain the sealing performance of clearance seal, the results shows that the sealing performance of clearance seal is mainly controlled by the width of the gap, the sealing clearance application of the impact of the cylinder sealing between the piston and cylinder, the gap width should be controlled at 0.2mm or less.Secondly, the mathematical model of clearance seal structure between the piston and the cylinder when the piston movement is established, the pressure field, velocity field and leakage of sealing clearance for sealing clearance chance ranges from 0.1mm to 0.5mm, the piston speed change from-3m/s to 7m/s, seal clearance of import and input pressure ranges from 0.3MPa to 0.5MPa are numerical studied. The linear regression method is adopted to analysis the performance, the result shows that, when the piston velocity is constant, the leakage linearly increases with the inlet pressure, and when the piston movement at different speeds, the leakage rate is equal. When the operating pressure of the seal clearance inlet is constant, with the width of the sealing gap increases, the leakage growth with the growth rate of the piston speed becomes quickly, indicating that clearance sealing width to the leakage size and growth rate plays a decisive role.Finally, the experimental test system set up by the pressure sensor, high-speed industrial cameras, vibration analyzer, data acquisition and so on, and the performance seal clearance in the cylinder reciprocating impact application leakage and life are studied experimentally. When the operating pressure is 0.4MPa, sealing gap width is 0.1mm, the impact number of the impact cylinder can reach 110,000 times. The life of the impact cylinder of using clearance seal structure is significantly higher than using the structure of the sealing ring, and the clearance seal arrangement significantly reduces the frictional force between the cylinder piston and cylinder to ensure that the cylinder impact energy.