考虑磨损效应的指尖密封瞬态泄漏特性分析

Transient Leakage Characteristics Analysis of Finger Seal Considering Wear Effects

关键词:  接触式指尖密封  磨损  多孔介质模型  瞬态泄漏特性  旋转机械

Key words:  Contacting finger seal  Wear  Porous media model  Transient leakage characteristics  Rotating machinery

摘要:

接触式指尖密封在工作过程中不可避免地会发生磨损，而磨损又会改变其泄漏特性进而影响旋转机械的效率。为了揭示磨损对指尖密封泄漏特性的影响规律，在指尖密封多孔介质流动分析模型的基础之上，建立了考虑转子离心膨胀和磨损效应的指尖密封瞬态泄漏特性数值分析模型，数值研究了转速和安装过盈量对指尖密封磨损及其对应的泄漏特性的影响规律。结果表明：考虑磨损效应时，指尖密封泄漏量随磨损时间的增加呈现出先减小后增大的趋势；转子转速越低，泄漏量降低至最小值所需的磨损时间越长，但最小泄漏量及其所对应的瞬态配合过盈量始终一致；安装过盈量越小，泄漏量降低至最小值所需的磨损时间越短，但最小泄漏量所对应的瞬态配合过盈量始终一致；此外，在任意磨损时刻，密封上下游压差越大泄漏量也越大。

Abstract:

Contacting finger seal is inevitably worn during the working process. Then wear will affect the leakage characteristics of the seal and the efficiency of the rotating machinery. In order to study the effects of wear on the leakage characteristics of finger seal， the authors proposed a transient leakage characteristics analysis model of finger seal based on the porous medium leakage analysis model while the centrifugal expansion of rotor and wear effect are considered， and the effects of rotating speed and initial assembly interference on wear and its corresponding leakage characteristics of finger seal are also numerically simulated. Results indicated that the leakage characteristics of finger seal decrease at first and then increase with runtime while wear effect is considered. The lower the rotating speed is， the longer the runtime required to reach the minimum leakage of finger seal， however， the minimum leakages and their corresponding transient fit interferences are the same at each rotating speed. The smaller the initial assembly interference is， the shorter the runtime required to reach the minimum leakage of finger seal， however， the transient fit interferences corresponding to the minimum leakages are the same at each initial assembly interference. In addition， the larger the pressure difference across the seal is， the larger the leakage of finger seal at arbitrary runtime.