Detailed Program of the 22nd ISC 2024
Study of the non-contact seals influence on the centrifugal machine’s dynamic characteristics.
Summary
Higher parameters of centrifugal machines are constantly required, such as the pressure of the medium to be sealed and the speed of rotation of the shaft. However, as the parameters increase, it becomes more and more difficult to ensure the effectiveness of sealing. Non-contact seals, in addition to sealing, perform an equally important function – to improve the vibration state of the centrifugal machine. Design measures aimed at increasing the hydraulic resistance of seals, as a rule, increase their hydrostatic stiffness and damping and thus improve their dynamic qualities. Non-contact seals are considered as hydrostatic-dynamic bearings that can effectively dampen rotor oscillations, and as automatic control systems. Models of systems "rotor-gap seals", impulse seals, "rotor-hydraulic face" and seals-supports of a shaftless pump have been studied to assess the effect of seal systems on the oscillatory characteristics of the rotor. Analytical dependencies are obtained for calculating the dynamic characteristics and stability limits of seals as hydromechanical systems.
The directions for improving the safety of operation of critical pumping equipment due to a targeted increase in the rigidity of non-contact seals are determined, which leads to an increase in the vibration resistance of the centrifugal machine’s rotor.
A general algorithm for constructing the dynamic characteristics of non-contact seals due to their hydrodynamic properties created and the directions for purposefully changing the parameters of sealing units to improve vibration characteristics determined. Expressions are obtained for calculating the amplitude and phase frequency characteristics, as well as for assessing the dynamic stability of various sealing units. The proposed general technique makes it possible to purposefully select the design parameters of seals to adjust sealing systems to work in vibration-safe modes.