Sealing Performance of Liquid Films in Composite Textures with Elliptical Dent–Herringbone Groove of Centrifugal Pump

To improve the lubrication stability of centrifugal pump mechanical seals under high-speed and high-pressure conditions, a composite texture combining elliptical dimples and herringbone grooves is proposed. The Hybrid Groove–Ellipse (HGE) configuration aims to enhance hydrodynamic pressure generation and mitigate thermal accumulation within the sealing interface. A thermohydrodynamic (THD) lubrication model with cavitation was established, and the coupled governing equations were solved using the finite volume method over 600–6000 rpm and 0.1–1 MPa. The lubrication performance of circular, rectangular, and two elliptical textures was systematically evaluated to identify their hydrodynamic characteristics. The ellipse with major axis parallel to the flow direction exhibited the most favorable pressure distribution and load-carrying capacity. Based on this geometry, the HGE structure was developed. Compared with conventional herringbone grooves, the HGE texture increases local pressure buildup, improves the load-carrying-to-leakage ratio, and modifies cavitation distribution. The maximum interface temperature is reduced by approximately 10–20% under high-speed conditions, with improved temperature uniformity. These results demonstrate that geometric coupling can enhance both the hydrodynamic and thermal performance of mechanical seals.