复合材料密封环局部高温热带生成的有限元建模与影响因素  

Finite Element Modeling on Appearance of Local Hot Bandings of Composite Sealing Ring and Relevant Influence Factors

作　　者：宫燃[1] 车华军[1] 张鹤[2] 徐宜[2] 

机构地区：[1]江苏大学汽车与交通工程学院,镇江212013 [2]中国北方车辆研究所,北京100072

出　　处：《机械工程学报》2017年第23期157-164,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51675238);中国博士后科学基金(2017M610301);江苏省"六大人才高峰"高层次人才(2014-JXQC-005);江苏大学科技项目青年扶持基金(FCJJ005)资助项目

摘　　要：结合密封环的工作特点和结构形式,提出密封环在接触过程中局部高温热带生成的模拟方法。基于伽辽金有限元算法,构建密封系统的热传导、热流密度、温度场扰动等非均匀特性的物理模型,及其各物理场之间的耦合关系,将密封环局部高温热带的热不稳定问题转化为矩阵行列式,并进行求解,可以获得在不同的摩擦条件下,发生局部高温热带的临界速度值。同时,模拟计算获得了临界速度与摩擦因数、弹性模量、导热系数、热膨胀系数和密封环尺寸的关系曲线。除导热系数外,其余几个因素对生成高温热带的临界速度影响较大。利用密封系统试验台进行结果分析和模型验证,在高温热带的临界速度方面,试验结果与模拟计算保持一致。通过扫描电子显微镜进行密封表面形貌分析,在试验速度高于临界速度的条件下进行试验后,密封表面出现明显的带状磨痕,与高温热带特征有较高的吻合度,表明有限元离散模型在密封热不稳定研究方面的适用性。According to the characteristics of working conditions and structures of sealing rings, a modeling method is presented to simulate the appearance of local hot bandings on the seal frictional pair. Based on the Galerkin finite element formulation, the physical models with non-uniform characteristics and coupling relationships of physical fields are built including heat conduction, heat flux, perturbations of temperature field and so on. The formulations about the thermal instability of local hot banding are transformed into the determinants of matrixes, and the solutions are carried out. The critical speeds for the appearances of hot bandings are obtained under different frictional conditions. And the relationship curves between the critical speed and frictional coefficient, elastic modulus, thermal conductivity, coefficient of thermal expansion, and sealing ring size are determined. In addition to the thermal conductivity, other factors have significant effects on the critical speed. Experimental investigations are performed in the sealing performance test rig, by comparison of numerical and experimental critical speed results to enable an assessment of the accuracy level. Scanning electron microscopy is utilized to examine the surface morphology of the sealing rings. The obvious banding scratches are observed on the sealing surface under the condition that the experimental speeds are greater than the calculated critical speeds, which agree well with the characteristics of hot bandings. The numerical and experimental results indicate the effectiveness of the finite element discrete model on simulations of the thermal instability.

关 键 词：密封环 高温热带 有限元 临界速度 

分 类 号：TH117[机械工程—机械设计及理论]