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Enhancing Film Stiffness of Spiral Groove Dry Gas Seal via Shape Modification at Low Speed: Numerical Results and Experiment

Abstract The film stiffness of dry gas seal must be sufficient to keep gas film stable at high and low speed. A generalized geometric model based on triangles is proposed to characterize spiral grooves. A mathematical model is established and solved using the finite-difference method to obtain steady performance. The optimum spiral grooves for maximum opening force and film stiffness are obtained at low speed, and their steady performance is compared with conventional spiral grooves numerically and experimentally. The pressure and flow field of optimum spiral grooves and conventional spiral grooves are simulated to reveal the mechanism of the performance difference. Results show that through-combined spiral grooves outperform the other derived spiral grooves. Their film stiffness is up to 15% larger than that of conventional spiral grooves at low speed.