Performance Analysis of the Self-Pumping Hydrodynamic Mechanical Seal with a Conical Convergent Diffuser Groove

Requirements such as high opening force, low leakage rate, and design without matching auxiliary flushing systems are expected of the modern fluid machinery shaft seals used in the process industry. A self-pumping hydrodynamic mechanical seal with a conical convergent diffuser groove is proposed and its sealing performance is studied by numerical simulation in this paper. Further, its sealing performance is compared to that of a flat-bottomed equal cross-sectional diffuser groove and the results have shown that the proposed seal has more superior sealing performance. The influence of structural and operating parameters on the sealing performance of the proposed seal is discussed and its working mechanism is explained. The results have shown that when the structural parameters of the spiral groove and the operating parameters are the same, the proposed design has a similar leakage rate and a higher opening force. The conical convergent diffuser groove has better wrapping properties, whereas the fluid energy is utilized more efficiently, improving the sealing interface opening force. The taper degree variation causes a slight change to the pressure at the root of the spiral groove, causing slight fluctuations in the seal leakage rate. The research results broaden the design of non-contact mechanical seals and provide a theoretical basis for the engineering application of the proposed self-pumping hydrodynamic mechanical seal with a conical convergent diffuser groove.