新型柱面气膜密封的设计与试验

Design and Test of New Column Surface Gas Film Seal

由于流体旋转机械面临复杂工况与交变载荷,导致其轴端采用的常规密封无法满足工况要求,因此研发一种低泄漏、高稳定与长寿命的密封变得尤为重要。基于浮动环的浮动性以及微槽的动压特性,研制了具有浮动与微槽特性的新型柱面气膜密封。对柱面气膜密封的界面形状进行设计与优化:流线型斜槽、矩形槽、优化流线型斜槽、优化矩形槽;使用3D光纤激光打标机对柱面旋转环进行表面槽型雕刻;搭建试验系统并分析不同工况、槽型下柱面气膜密封泄漏量的变化规律,观察轴套和浮动环表面的擦痕轨迹。试验结果表明:当压力流一定时,随着转速的增加,4种微槽的泄漏量都有所下降逐渐趋于稳定,并且优化槽的泄漏量明显小于原始槽,当转速一定时,压力的上升导致4种槽型泄漏量急剧上升,近乎呈线性分布。

For the fluid rotating machine facing complex working conditions and alternating load, so that the normal sealing used by the shaft end is not able to satisfy the requirements of working conditions, therefore, it is extremely important to develop a sealing with low leakage, high stability and long service life.The new column surface gas film seal with floating and microgroove characteristics is developed based on the floating characteristics of the floating ring and the dynamic pressure features of the microgroove.Design and optimization for the interface shape have been carried out to the column surface gas film seal: Inswept skewed slot, rectangular slot, improved inswept skewed slot and improved rectangular slot;The 3 D optical fiber laser marker is used to carve on the surface of the cylindrical rotating ring;The test system is established to analyze different working conditions, the change rule of the column surface gas film sealing leakage rate under the groove profile, and observe the scratch track of the shaft sleeve and the surface of the floating ring.The test results show that: When the pressure flow is fixed, with the increasing of the rotating speed, the leakage rate of the four microgrooves reduces and gradually stabilizes, in addition, the leakage volume of the improved slot is obviously smaller than the original slot.When the rotating speed is fixed, the increasing of the pressure leads to rapid increase of the leakage volume of the four slots, and the trend is in linear distribution.