Analyses of both steady behavior and dynamic tracking of non-contacting spiral-grooved gas face seals

Abstract

The analyses for steady and unsteady sealing behaviors of spiral-grooved gas face seals are presented by finite element method. The element with nine nodes and four quadratic cures is used. And for avoiding the film thickness discontinuity over the grooves, two of them coincide with the circular arcs and the others approximate to the spiral lines. In steady-state analysis, the steady-state Reynolds equation is used, and different element meshes are utilized for different sealed pressures. The load capacity and the lubricant leakage on gas face seals are shown for different compressibility numbers and sealed pressures. Thus the optimal sealed pressure and the gas amount needed in actual applications can be determined according to the numerical results. For the dynamic tracking of the stator, the direct-dynamic analysis is used, and the explicit form of the unsteady compressible Reynolds equation is found by weighting the film thickness in each element. The initial pressure profile and the initial closing force are determined at the given sealed pressure. The dislocations due to the external shock disturbances are considered, including the rotor runout only, the stator misalignment only, and the mixed dislocations. The possibility of face contact, the detectable central clearance between stator and rotor, and the leakage under unsteady operation are concerned.