Stiffness characteristics of spiral grooved face seals

To solve the stiffness design problems of spiral grooved face seals in different working conditions, the stiffness coefficient was numerically calculated, and the influencing factors of stiffness were analyzed. The Possion's equation was used to generate boundary-fitted coordinate (BFC) grid system, and spiral curvilinear grid system was obtained with a coincident boundary of irregular physical area. Applying finite difference method (FDM) based on BFC, the Reynolds equation was discretized and numerically calculated in the computational plane. The effects of rotational speed and the ratio of inner radius over the outer radius on stiffness were analyzed. It was found that the lubricant film obtained the biggest stiffness coefficient when the radius ratio was 0.5~0.6 on the condition that the test parameters were fixed. With outer radius increasing, the stiffness increased and the effect of radius ratio was more significant. The stiffness coefficient increased linearly with increasing rotational speed, and a maximum coefficient was observed when the radius ratio was 0.5~0.6. For the narrow face seals, when stiffness coefficient was deficient which is caused from an increased perturbation that is proportional to the rotational speed, a larger radius ratio will be necessary to ensure the seals work properly.