Multiphase flow sealing performance analysis of a novel dual-blade shaft end seal structure for high-speed train gearboxes

This study introduces a new shaft-end sealing structure for high-speed train gearboxes (HTG-NSS), designed to address lubricant leakage caused by external negative pressure environments, such as when trains travel through tunnels. The HTG-NSS features a dual-blade impeller structure, which combines symmetrically arranged dual blades with a straight-through labyrinth seal. In comparison with traditional interlocking shaft-end seals and oil-slinger ring seals, the HTG-NSS offers superior sealing performance and a more compact design. To evaluate its effectiveness, this study combines multiphase flow simulation analysis with experimental validation, examining key parameters such as the number of impeller blades, blade angle, and the inner diameter of the impeller outer edge (IDIOE). The sealing performance is assessed using metrics like lubricant leakage mass flow rate, turbulent dissipation rate, and turbulent kinetic energy. The findings show that the HTG-NSS reduces lubricant leakage by 61.28% compared to conventional oil-fling ring seals. The dual-blade impeller with a 90° blade angle increases turbulent dissipation, minimizing leakage, with the maximum turbulent dissipation rate reaching <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>.</mml:mo> <mml:mn>12</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> <mml:msup> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">/</mml:mo> <mml:msup> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . Additionally, an IDIOE of 110 mm further reduces leakage by 14.77%, lowering the outlet leakage rate to 0.91 g/s. The HTG-NSS offers a non-contact sealing solution inspired by oil-gas mixed transport pumps, which significantly reduces leakage and enhances gearbox sealing performance.