| With the rapid development of modern industry,rotating mechanical equipment is widely used in many fields of life,such as chemical industry and transportation,which greatly improves the quality of people's daily life.Due to the current scientific development trend of advocating people to protect the environment,the sealing equipment in practical engineering application is becoming more and more extreme due to the working condition parameters.As a common shaft end seal of rotating machinery,it can not meet the current demand of advocating"zero leakage"of rotating machinery.However,the cylindrical spiral groove gas film seal can adapt to extreme working conditions such as low pressure,high speed and high temperature,and has good stability,less leakage,long service life and other excellent performance in the working process,which has become a new focus of the research on the shaft end seal of rotating machinery.Therefore,the research on the sealing performance of the cylindrical spiral groove gas film seal system is of great significance to improve the running stability of the shaft end seal and reduce the leakage Righteousness.Based on a series of assumptions,the Reynolds equation and the film thickness control equation for the pressure control of cylinder spiral groove gas film seal are introduced and derived.Newton Raphson iterative method and finite difference method are used to solve the Reynolds equation and the film thickness equation by combining the pressure boundary conditions.Through software programming,it is found that a certain number of spiral grooves are carved on the shaft sleeve of the cylindrical spiral groove gas film seal,which can improve the air film floating lift and running stability of the seal device.The results show that the increase of inlet pressure,rotating speed and number of grooves are beneficial to the increase of air film buoyancy,but the increase of air film thickness and groove depth results in the decrease of buoyancy;the leakage decreases with the increase of rotating speed and groove number,and increases with the increase of air film thickness,inlet pressure and groove depth;and the rigidity of air film increases with the increase of rotating speed and pressure With the increase of the thickness of the gas film,the stiffness of the gas film increases first and then decreases.The influence of some working conditions and groove parameters on the performance of cylinder spiral groove gas film seal is obtained,which provides theoretical guidance for the next test of cylinder gas film seal performance and reduces the test cost.Based on the back-to-back style of dry gas seal,the design of cylinder spiral groove gas film seal test prototype provides theoretical guidance for the construction of cylinder spiral groove gas film seal test system.In order to obtain the numerical signal measured in the experiment,some anti-interference measures are taken to protect the collected signal during the experiment,and the signal transmission equipment conforming to the test conditions is selected to compare the test data with the numerical calculation results.The results show that:under the condition of changing the inlet pressure,the air film buoyancy,leakage and rigidity measured by the air film seal prototype test system increase with the increase of the pressure,and the measured value and the theoretical calculation value are relatively close;the maximum phase error of the air film buoyancy is10.61%,the maximum relative error of the leakage is 14.72%,and the maximum relative error of the air film rigidity is 14.72%The difference is16.27%;when the motor operates at different speeds,the air film buoyancy and air film stiffness increase with the increase of rotating speed,while the leakage decreases with the increase of rotating speed,but the decrease is not significant;the maximum relative error of air film buoyancy is 11.28%,the maximum relative error of leakage is 14.62%,and the maximum relative error of air film stiffness is 13.02%.Although there are some errors between the values,they are all within the acceptable range.Therefore,the sealing performance of the cylindrical spiral groove gas film seal is studied in depth.Although there are some errors in the experimental test,the comparison between the test results of the sealing performance of the cylindrical spiral groove gas film seal and the numerical trend of the theoretical calculation results is in good agreement,so as to verify the correctness of the theoretical calculation in this paper.In order to improve the sealing performance and running stability of the cylindrical spiral groove gas film seal system,the influence of the sealing interface structure is significant.The leakage ratio T_k of the gas film is introduced to characterize the comprehensive performance of the cylinder spiral groove gas film seal,which provides a standard for the selection of the parameters range of the cylinder spiral groove gas film,and uses the one-dimensional direct elimination method to optimize the groove parameters.The conclusion is as follows:the helix angle is 28.5°,the number of grooves is 16,the depth of grooves is 4.3?m,and the sealing width is 4.5mm.Compared the three-dimensional pressure distribution of the cylinder spiral groove gas film before and after optimization,the local pressure of the optimized cylinder gas film sealing device is more significant,and the three-dimensional figure is more flat,with fewer burrs.Therefore,the groove type optimization is of great help to improve the stability of the cylinder gas film seal device,and the research results of the spiral groove type optimization can provide a reference for the future theoretical model modification of the cylinder spiral groove gas film seal and quantitative analysis of the test. |
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