| Dry gas seal is widely used as shaft end seals for rotating machinery because of low loss and leakage.Its design and development involves various aspects such as device structure,material selection,and installation methods,among them,the lubricating film between the auxiliary pairs is key to the sealing performance.When the dry gas sealing system under stable processing condition,the micro-gap of the static and dynamic sealing pair keeps the device in a fluid lubrication state,the corresponding main friction is derived from the internal friction between the fluids..With the development of rotating machinery to extreme working conditions,large-scale structural parameters,diversified media types,etc,the friction effect of dry gas-sealed lubricating gas film is increasingly prominent,the service life of the dry gas seal system is severely shortened due to the temperature rise of the end face and the thermal deformation of the friction pair.It can be seen that it is of great significance to study the friction characteristics of dry gas seal lubricating film.In the paper,the spiral groove dry gas seal structure is based on MATLAB software,the central differential method and the super-relaxation iterative method are used to solve the gas film pressure control equation and the film thickness control equation to obtain the lubrication film thickness and pressure distribution.At the same time,the three-dimensional calculation model of gas film was established,and the structured grid was divided by ICEM,and the flow field was simulated by Fluent.The film opening force and the film friction were selected as the comparison targets.The analysis showed that the calculated results of the two methods were in agreement,and the maximum relative difference percentage was 5.96%.With the research on the frictional characteristics of the spiral groove dry gas seal film,combined with the above two numerical calculation methods,the working condition parameters and the groove structure parameters were changed for example analysis.The results show that when the dry gas sealing system is in the film lubrication state,the gas film friction characteristic parameters are greatly affected by the working condition parameters,and are less affected by the structural parameters.Among them,the frictional power consumption of the lubricating film increases linearly with the increase of the rotational speed,and decrease with the increase of average film thickness and groove depth,but the change of medium pressure and helix angle has little effect on frictional power consumption.The friction coefficientrepresents the relationship between shear flow and differential pressure flow to some extent,with the increase of rotational speed and medium pressure the coefficient of friction of the lubricating film decreases,but when the pressure of the medium increases to a certain value,the coefficient of friction of the film tends to be gentle.The temperature rise of viscous dissipation is most affected by the pressure of the medium,and larger pressure drop causes the dissipation temperature to rise more.temperature rise,secondly,the increase of the rotational speed causes the viscous force to increase the work,which causes the dissipation temperature to rise.In the range of the spiral angle of 75 degrees to 76 degrees,the variation of consumption.temperature rise is relatively stable.Therefore,under high-pressure,high-speed operating conditions,the friction of the lubricating film can not be ignored.The research results of this subject lay the foundation for the quantitative optimization analysis of dry gas seals and the theoretical study of lubricating gas films,can providing a reliable reference for the application of dry gas seals in engineering. |
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