2.5D碳/碳复合材料指尖密封动态性能分析

Analysis of Dynamic Performance for 2.5D Carbon-carbon Composite Finger Seals

指尖密封的泄漏与磨损一直是影响其工作性能和寿命的重要因素,且因两者性能改善途径的相互制约,使得指尖密封的优化设计举措难以两全,迄今尚无更好的技术解决这一难题。采用诸如碳/碳复合材料制备指尖密封零件,利用碳/碳复合材料具有的自润滑功能以更多地关注密封泄漏性能的改善,可能是改善上述研究现状的可行技术途径,而作为设计理论的基础,开展碳/碳复合材料指尖密封性能分析是很有意义的工作。论文利用细观组分材料的性能来计算2.5D碳/碳复合材料刚度矩阵,由此预测材料宏观弹性性能,建立2.5D碳/碳复合材料指尖密封动态性能分析的有限元模型,研究材料纱线密度和纱线编织结构对指尖密封动态性能的影响规律。研究结果表明:增大指尖密封圆周方向上的纱线密度、采用浅交直联纱线编织结构都可以显著提高指尖密封的密封性能,较之金属材料指尖密封,2.5D碳/碳复合材料指尖密封的动态性能表现出更好的品质。本文研究支持了碳/碳复合材料应用于指尖密封制备的可行性。

Leakage and wear of a finger seal are two key factors that affect seal dynamic performance and service life. Op- timum design of a finger seal structure is difficult to realize because of the mutual suppression between the two factors in seal performance improvement. Oarbon-carbon composites are applied to finger seal component preparation to improve seal per- formance for its self-lubrication property, which may prove to be a most feasible solution to this issue. It is meaningful work to carry out an analysis for carbon-carbon composite finger seal performance to provide the theoretical basis for its design. This paper evaluated the elastic properties of the materials by using the constituent material properties to calculate the stiff- ness matrix of the 2.5D carbon-carbon composites, and established a finite element model for carbon-carbon composite fin- ger seal dynamic performance analysis. By this model, the effects of yarn density and weaving mode on the dynamic per- formance of finger seals are studied. The results show that increasing the yarn density in the circumferential direction of the finger seal and using shallow direct-joint structure can improve the finger seal dynamic performance. Finally, compared with metalseals, the 2.5D carbon-carbon composite finger seal exhibits better seal dynamic performance. The study shows that it is feasible to use carbon-carbon composites for finger seal component preparation.