端面变形对液体动压型机械密封液膜瞬态特性的影响

Influence of end face deformation on transient characteristics of fluid film in hydrodynamic mechanical seal

建立动环-液膜-静环动压型机械密封双向流固耦合模型,针对逆流泵送状态,对密封环及液膜流场进行非定常耦合计算,分析了密封环变形和液膜压力的瞬态特性,并通过流固耦合前后流场对比,分析了密封环端面变形对液膜压力脉动的影响。研究结果表明:与未考虑变形时相比,双向流固耦合计算结果更加符合实际;静环端面变形随时间呈周期性变化,且越靠近内径出口处,变形量的波动程度越大;密封环端面变形对外径处压力脉动影响较小,但会明显增强内径处压力脉动,且转速越大,压力脉动增强的程度越大,介质压力在压力较低的工况下对变形后液膜压力脉动程度的影响不明显;密封环端面的变形只影响压力脉动的程度,不改变压力脉动的频率。

The two-way fluid-solid interaction model of rotating ring-fluid film-stationary ring was established in hydrodynamic mechanical seal. Unsteady simulations were carried on at the upstream pumping state. The transient characteristics of the deformation of sealing ring and the pressure of the fluid film were studied, and the influence of the end face deformation on the pressure fluctuation was discussed by comparing the results before and after fluid-solid interaction. The results show that comparing the simulation without the deformation, the results obtained by fluid-solid-interaction are more realistic. The end face deformations of stationary ring is fluctuating like pressure fluctuation with same period, and the closer to the outlet at the inner diameter, the greater degree of the deformation fluctuation. The degree of pressure fluctuation is from big to small from inner diameter to outer. The end face deformation of sealing ring affects the pressure fluctuation slightly at the outer diameter, while enhances the pressure fluctuation at the inner diameter obviously, and the degree of the enhancement is greater with the increase of rotational speed, the influence of the sealing medium pressure is not obvious under the low pressure condition after fluid-solid interaction. The end face deformation of the sealing ring only affects the degree of the pressure fluctuation without changing the frequency of the pressure fluctuation.