Abstract:

For aeroengine cylinder seals, the floating ring is often broken due to insufficient dynamic pressure, which causes the floating ring to rub against. Based on this, the Fluent software is used to simulate the flow field of two kinds of models, namely, the existing cylindrical grooved gas film and the spiral grooved gas film, and carry out with test verification. The results show that for the grooveless gas film model, increasing the eccentricity, rotation speed and pressure difference will increase the dynamic pressure effect of the seal. The increase of eccentricity and pressure difference will increase the leakage of the model, but the change of rotation speed has little effect on the leakage of the model; for spiral groove gas film seal, the increase of eccentricity, rotation speed and pressure difference will increase the buoyancy of the gas film. With the increase of eccentricity and pressure difference, the leakage of the model increases. Based on the above two conclusions, it can be concluded that the speed is the secondary factor affecting the leakage; the spiral groove model has better dynamic pressure effect and less leakage compared with the grooveless model, so it can reduce the friction of floating ring. Therefore, this study has important reference significance for the development of better cylindrical seal structure.

Key words: cylinder seal, gas film, dynamic pressure effect, test verification, numerical simulation

摘要：

航空发动机柱面密封常因动压不足导致浮环碰磨而破裂。据此利用Fluent软件对现役柱面无槽气膜和螺旋槽气膜两种模型进行了流场动压数值模拟，并进行试验验证。研究结果表明：对于无槽气膜模型，增大偏心率、转速和压差，密封动压效应增强。偏心率和压差的增大会提高模型泄漏率，但转速的改变对模型泄漏率的影响很小；对于螺旋槽气膜密封，增大偏心率、转速和压差，气膜浮升力提升。随偏心率和压差的增大，模型泄漏率随之升高。综合以上两条结论可得，转速是影响泄漏率的次要因素；螺旋槽模型相对无槽模型，动压效果好，泄漏率小，相同工况下具有更好的动压效应，此研究对于研发更优的柱面密封结构有重要参考意义。

关键词: 柱面密封, 气膜, 动压效应, 试验验证, 数值模拟