Design And Performance Research Of Rotary Sealing Device For High Pressure Water Jet Roadheader

In order to solve the problems of easy wear and short service life of rotary seal device in high-pressure water jet roadheader,a high-pressure rotary seal device with high reliability and automatic compensation for wear is proposed.On the basis of not changing the original structure of the roadheader cutting system,it is installed at the back end of the cutting arm of the roadheader to realize the purpose of introducing highpressure water jet to complete the rotary seal.This thesis adopts the form of theoretical calculation,experiment and numerical simulation to design the structure of the highpressure rotary device and replace the sealing parts of different materials to test its sealing performance.According to the design parameters of the high-pressure rotary seal device and the sealing principle of the existing rotary seal device,a rotary seal device suitable for the cutting system of the high-pressure water jet roadheader is designed.The special structure of the rotary seal device,such as the flow channel,the sealing guide sleeve and the sealing seat,makes it capable of automatic compensation of wear.The structural strength of rotary sealing device under high pressure environment is studied based on unidirectional flow solid coupling method.The high pressure water in the flow channel is simulated and the analysis results are applied to the solid structure as the load.The results show that the structural strength of the designed rotary sealing device meets the working requirements under high pressure environment.The high pressure rotary seal test bench was built to study the sealing performance of the high pressure rotary seal device.The static torque,leakage and temperature rise of the end face of the sealing device are taken as the evaluation indexes of the sealing performance,and the rotating shaft speed,high pressure water pressure and the combination of different materials are taken as the influencing factors of the sealing performance.Through friction torque test,leakage test and temperature rise test,the sealing performance of different seal combinations under various test conditions is studied.The results show that PVDF-stainless steel and Peek-stainless steel have better sealing performance and are more suitable for the sealing guide sleeve and sealing valve seat materials.In order to study the temperature rise of the seal end face more intuitively,numerical simulation of the seal guide sleeve and the seal seat is carried out based on the heat-structure coupling method and the heat-fluid-solid coupling method,and the strain field distribution,temperature field distribution and temperature rise curve of the seal are obtained.By analyzing the simulation results,it is found that the influence law of rotating shaft speed and medium pressure on the temperature of the seal,the temperature distribution of the sealing guide sleeve and the sealing seat along the axial and radial direction,and the deformation law of the sealing guide sleeve.The simulation results are compared with the test results.The results show that PVDF-stainless steel seal combination has the lowest stable temperature,the least influence by speed,load and other conditions,and the best sealing performance.In order to further study the wear resistance of different seal combinations,the friction and wear test was carried out based on the high pressure rotary seal test bench,and the friction and wear simulation was carried out based on the Archard wear model,and the influence law of rotating shaft speed and medium pressure on the wear of the seal was studied.The wear volume curve and friction stress curve of different materials were compared and analyzed.The results show that PVDF has the best wear resistance.By studying the strain nephogram of the seal,the law of the wear deformation of the seal is found,and verified by the appearance characteristics of the seal end face after the wear test.This thesis has 84 figures,20 tables and 110 references.