Surface Groove Design And Inertia Effect And Turbulent Effect Analysis Of High Parameter Dry Gas Seal

Non-contacting dry gas seal has become the preferred seal for high-speed centrifugal compressor and supercritical CO₂?S-CO₂?power equipment because of its excellent low leakage and low power consumption characteristics.It is also a strong competitor for super-high-speed aeroengine gas seal.However,the gas inertia and turbulence effects caused by high-speed or low-viscosity,high-density supercritical-fluids are prominent,which makes the film pressure calculated by classical Reynolds equation which ignores inertia and based on laminar flow assumption have larger errors,and the prediction accuracy of stable and dynamic seal characteristics needs to be improved.With the further development of power equipment toward ultra-high speed or supercritical,considering inertia and turbulence effects to obtain a more accurate numerical analysis model of dry gas seals,optimizing the structure of sealing end grooves has important theoretical and engineering value for the performance prediction and engineering design of dry gas seals for ultra-high speed and S-CO₂ power equipment.Taking super-high-speed ideal gas dry gas seal as the research object,a numerical solution model of steady and dynamic characteristics of dry gas seal considering inertia effect was established.The influence of inertia effect on the stability and dynamic characteristics of gas film seals with parallel and inclined ends at ultra-high speed is analyzed numerically.The pressure and velocity fields of gas film with and without inertia effect are compared and analyzed.The influence of inertia effect on the stability and leakage characteristics of gas film is revealed,and the optimization of helical groove structure parameters considering inertia effect is obtained value.Taking high-pressure,high-speed and S-CO₂ dry gas seal as the research object,a practical modified numerical solution model considering actual gas effect,inertia effect and actual flow pattern was established.The steady-state performance of high-speed S-CO₂ dry gas seal based on the actual modified model and the classical simplified model was compared and analyzed under two typical working conditions:near-critical point and far-critical point.The effects of actual gas effect,inertia effect and turbulence effect on film stiffness and leakage rate under different media pressures and velocities were analyzed,and the effects of three effects on steady-state seal performance were revealed.The optimum parameters of helical groove structure considering turbulence and inertia effects are obtained by the single influence and interaction mechanism.Taking high-pressure,high-speed and S-CO₂ dry gas seal as the research object,a practical modified numerical solution model considering actual gas effect,inertia effect and actual flow pattern was established.The steady-state performance of high-speed S-CO₂ dry gas seal based on the actual modified model and the classical simplified model was compared and analyzed under two typical working conditions:near-critical point and far-critical point.The effects of actual gas effect,inertia effect and turbulence effect on film stiffness and leakage rate under different media pressures and velocities were analyzed,and the effects of three effects on steady-state seal performance were revealed.The optimum parameters of spiral groove structure under three effects were obtained.A super elliptic curve groove with stronger geometric characterization ability was introduced.Based on different multi-parameter optimization algorithms,the optimal geometric parameters matching of super elliptic curve groove for super high speed ideal gas dry seal and high pressure S-CO₂ dry gas seal was obtained.The optimization results could be used for high parameter dry gas seal.The groove profile selection and parameter design can provide reference.