关键词: 操作参数, 干气密封, T型槽, 密封性能, 有限元法

Abstract: Dry gas seals with T-grooves onto its faces have been widely used in axial seal of a centrifugal compressor in petro-refinery and chemical process. The failures of such seals cannot be diagnosed correctly due to the lack of the theory of such seal geometric construction. In this paper, a finite element analysis was used to resolve Reynolds equation for the gas flow between the two faces of a non-contacting T-groove dry gas seal based on gas lubrication theory. The maximum value of gas film stiffness was selected as the optimization object for T-grooved face geometric parameters. The diversification law of opening force, leakage rate and gas film stiffness varied with geometric parameters of T-grooves in the different rotational speeds or sealed medium pressures was analyzed. The results showed that the rotational speed has great effect on the optimization values of T-groove geometric parameters, such as arc ratio α1, groove width ratio α2 and groove depth hg, but he effect of rotational speed on the optimization value of radial ratio β1 and groove length ratio β2 can be ignored. The higher the rotational speed, the greater the optimization values of α1 and hg, but the lower the optimization value of α2. The effect of the sealed medium pressure on the optimization values of α1, β1 and hg was great to a certain degree, but to the optimization values of α2 and β2, the effect could be ignored. The sensitivity of opening force, leakage rate and film stiffness to the above five geometric parameter values of T-groove would be lower when the sealed medium pressure was higher. The optimization values of α1 and hg would be lower when the sealed medium pressure became higher, but the optimization value of β1 would be higher. The results would provide the theoretical support for the practical utilization under the condition of different operational parameters of a T-groove dry gas seal.

Key words: operating conditions, dry gas seal, T-groove, seal performance, finite analysis method