| Oil-gas two-phase hydrodynamic seal(OG-HS)is a high-performance mechanical seal based on fluid dynamic pressure effect.It has minimal leakage,long life and low power consumption,and solves the problem of traditional single-phase sealing under oil-gas two-phase lubrication conditions.The problems including large leakage,serious wear,large heat and poor reliability.At present,there are very few related researches on the dynamic characteristics of oil-gas two-phase sealing at internal and abroad.It is even rarer to consider the influence of the micro-scale deformation of the seal ring on the dynamic characteristics of the seals.In this paper,the dynamic performance,follow-up dynamic characteristics and self-vibration dynamic characteristics of oil-gas two-phase hydrodynamic seals before and after deformation are theoretically studied,and the experimental study of static ring vibration characteristics under variable speed and start-stop conditions is carried out.Considering the force deformation and thermal deformation of the seal ring,and the influence of the change of the fluid film thickness between the end faces on the dynamic characteristics of the seal,the finite element model of the fluid film and the seal ring is established in parallel in MATLAB by the calculation method of fluid-solid-thermal coupling.The finite element equations of the fluid film and the sealing ring are solved,and the temperature distribution of the sealing ring,the pressure distribution of the fluid film,the thermal deformation of the sealing ring end face and the force deformation are obtained.The dynamic model of the seal dynamic analysis is established.The linear perturbation method is used to solve the perturbation pressure control equation after sealing coupling in MATLAB.The eighteen dynamic characteristic parameters of the dynamic performance of the two-phase hydrodynamic seal are obtained.Analyze and calculate the deformation of the seal ring end-face before and after the seal fluid-solid-thermal coupling and the pressure distribution of the oil-gas two-phase fluid film to obtain the final film thickness.The characteristics and laws of the 18 dynamic performance parameters of the seal at different disturbance frequencies are calculated and analyzed.The changes of sealing dynamic performance parameters under different structural parameters and operating parameters before and after deformation of the end face were compared and analyzed.The value range of sealing structure parameters with excellent dynamic performance was obtained and summarized.Using the GUIDE tool in MATLAB,the GUI(graphical user interface)is quickly generated through visual editing method,and the versatile oil-gas two-phase hydrodynamic sealing fluid-solid-thermal coupling calculation software and dynamic performance calculation software are created to improve the simplicity and efficiency of fluid-solid-thermal coupling and dynamic performance calculations.Considering the static ring as a system with stiffness and damping characteristics,a dynamic model of static ring perturbation motion is established.The response motion of the static ring is characterized by stiffness and damping,the perturbation motion equation of the parallel static ring and the dynamic microscopic of the fluid film.The stress control equation is used to solve the iterative solution,and the criterion of sealing critical instability is obtained.The following follow-up dynamic characteristics and self-vibration dynamic characteristics of oil-gas two-phase hydrodynamic seal are studied.The analysis results show that the oil-gas two-phase hydrodynamic seal does not destabilize under normal working conditions.The oil-gas two-phase hydrodynamic seal test device was designed and manufactured,and a sealed test bench was built.The static pressure test,the variable speed running test and the start-stop test were carried out on the sealing device.The reliability of the oil-gas two-phase hydrodynamic seal under static pressure conditions is verified by experiments.The leakage,end face temperature,bearing temperature and static vibration characteristics of the oil-gas two-phase hydrodynamic seal at different speeds are obtained.The test results verify the correctness of the dynamic analysis theory of oil-gas two-phase hydrodynamic seal.This paper combines the fluid-solid-thermal coupling and dynamic characteristics of oil-gas two-phase hydrodynamic seal to provide the idea of optimizing the reliability,stability and anti-interference ability of oil-gas two-phase sealing,laying a foundation for the research and engineering design of oil and gas two-phase sealing.The theoretical basis has promoted the engineering application,promotion and development of oil-gas two-phase sealing. |
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