Numerical research on the inertial vortex flow mechanism and cooling law of L-shaped channels in contact mechanical seals

The research purpose is to reveal the flow, heat transfer enhancement and temperature rise control mechanism of a novel contact mechanical seal with L-shaped channels under high-speed conditions. To address the challenge of thermal failure caused by frictional heat, an innovative sealing structure with an integrated L-shaped channel in the rotor is proposed for efficient cooling. A three-dimensional turbulent conjugate heat transfer numerical model of the novel seal is established based on the SST k - ω turbulence model. Systematic analyses of the flow, temperature, velocity, and Nusselt number distributions reveal the mechanisms: Firstly, a forced convection is generated inside the L-shaped channel of rotor due to the high-speed rotation, significantly shortening the heat transfer path and improving thermal conduction efficiency; Secondly, the strong turbulent mixing generated by the medium flowing through the channel disrupts the near-wall thermal boundary layer, breaking the traditional thermal diffusion bottleneck in seals and accelerating the transfer of frictional heat from the end faces into the channels; Thirdly, the fluid flowing out of L-channel impinges on and disturbs the flow field in sealing chamber, homogenizing the flow state and thinning the thermal boundary layer on the outer side of rotor and stator. The synergistic effect of these three aspects allows for heat to be efficiently dissipated from the end faces into the chamber fluid. Results show that the novel structure significantly enhances the heat transfer performance and reduces the seal ring temperature rise: under 6000rpm conditions, the maximum end-face temperature decreases from 532 K to 443 K, with a 38% improvement in heat transfer efficiency, confirming its superior heat transfer enhancement and providing a scientific basis and feasible solution for the engineering design of high-speed contact mechanical seals.