Optimal parameters of elliptical groove gas film face seal with bidirectional rotational characteristics

The performance of gas film face seals is substantially affected by the geometric features of the texture on the seal face. To enhance the design of elliptical groove face seals for efficient bidirectional rotation, a comprehensive theoretical analysis of how key parameters influence bidirectional working performance is performed, and the optimal geometric configuration is identified. The gas Reynolds equation is solved via the finite difference method to numerically assess the influence of operating parameters, including linear velocity and medium pressure, and geometric parameters, including slenderness ratio, number of grooves, and groove radius, on gas film stiffness, leakage rate, and hydrodynamic opening rate. The results demonstrate that for inclined elliptical grooves, both gas film stiffness and hydrodynamic opening rate under positive rotation are significantly higher than those under negative rotation, resulting in increased sealing leakage. With increasing rotational speed, the gap in performance between the two directions of rotation widens progressively. Elevated medium pressure leads to a deterioration in hydrodynamic opening performance. Notably, a 90° elliptical groove gas film face seal exhibits superior bidirectional rotational characteristics. Moreover, an open and incomplete groove profile is recommended for enhanced performance, provided that the degree of incompleteness is maintained within rational engineering limits. To further improve the hydrodynamic opening performance, wider ranges of numbers of grooves and slenderness ratios may be employed, with optimal performance being achieved when the number of grooves is between 8 and 16 and the slenderness ratio is between 3 and 5.