Study on the Enhancing Mechanism of Thermal Mixing Effect in High-speed Mechanical Seals with the Cooling Channel at Sealing Face

doi:10.3901/JME.2025.13.246

Abstract

Abstract: To realize the temperature controllability of seals under high-speed conditions and increase the vaporization margin of the micro-scale lubricating liquid film, the thermohydrodynamic lubrication (THD) model of the mechanical seal with the inlet and annular groove cooling channel is developed by ANSYS Fluent, the flow characteristics of the hot and cold fluids in the groove area and its influence on the liquid film temperature are studied and discussed, the enhancing mechanism of thermal mixing effect is revealed, and the influences of structural size and operational parameters on the sealing performance are analyzed. The results show when the inlet is connected with the annular groove, the inhibition of the inlet root wall is eliminated, and the dead zone of fluid flow is avoided, and the flow capacity is enhanced, which significantly strengthens the mixed flow of outer low-temperature fluid and inner high-temperature fluid. It significantly improves the sealing cooling capacity, thereby effectively reducing the temperatures of the lubricating liquid film and sealing face. Due to the lower liquid film temperature, the fluid viscosity loss is smaller, resulting in stronger hydrodynamic effect and greater downstream pumping capacity, and the sealing load-carrying capacity and tribological performance are greatly improved. The higher the rotational speed, the stronger the enhancing level of thermal mixing effect, and the temperature of liquid film and sealing face is reduced by about 15 K and the temperature rise is reduced by about 36% at 20 000 r/min, which significantly increases the vaporization margin of the high-temperature liquid film at the low-pressure inner side of sealing face, and the opening force of liquid film is increased by about 30%. The optimal depth of the cooling channel is 50 μm, which gives the optimal strengthening level of thermal mixing effect, cooling capacity and sealing performance comprehensively. It significantly improves the vaporization margin of liquid film and limits the thermal deformation of sealing face under high-speed conditions, which provides a scientific basis for the optimal design of high-speed mechanical seals.

Key words: high-speed mechanical seal, temperature controllability, cooling channel, thermohydrodynamic lubrication, enhancing thermal mixing effect

CLC Number:

TH117

MA Xuezhong, CUI Yuanzhao. Study on the Enhancing Mechanism of Thermal Mixing Effect in High-speed Mechanical Seals with the Cooling Channel at Sealing Face[J]. Journal of Mechanical Engineering, 2025, 61(13): 246-254.

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