Leakage control design and performance analysis on upstream pumping compliant foil face gas seal

Purpose This study aims to explore how the seal face structure affects the gas flow and film performance, focusing on compliant foil face gas seal with an upstream pumping spiral gap. The research is done to reveal the leakage control mechanism and obtain the optimal parameters of structure. Design/methodology/approach A gas-elastic coupling lubrication model for compliant foil face gas seal is developed using gas lubrication and elastic mechanics theories. The finite difference method is applied to calculate film pressure, deformation and flow rate variations under varying gap spiral angles. What’s more, the impacts of equilibrium film thickness, rotational speed and medium pressure on sealing performances are researched, and the flexibility coefficients α 1 (dynamic pressure area) and α 2 (sealing area) are optimized. Findings This design significantly reduces leakage rates while maintaining the adaptive operation capability of compliant foil face gas seals. When α 1 takes values from 0.10 to 0.15, α 2 takes values from 0.5 to 0.6 and φ (gap spiral angle) is equal to 30°, the comprehensive performance of sealing in steady and transient states is better. Originality/value Integrating the design concept of upstream pumping dry gas seals and the adaptive structure of compliant foil face gas seals, a novel foil face gas seal structure with upstream pumping function is proposed. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2024-0434/