航空发动机燃油附件用橡胶密封圈的表面损伤分析

Analysis of Surface Damage of Rubber Seal Ring Used in Aircraft Engine Fuel Accessories

航空发动机燃油附件中的关键零组件O型密封圈对发动机的安全工作起着至关重要的作用。采用宏微观观察、红外光谱分析(FTIR)、差示扫描(DSC)和热失重(TGA)等试验方法,对航空发动机燃油附件用O型密封圈进行分析研究,并与同批次使用前后密封圈的断口形貌及热物性进行对比。结果表明,经过550 h装机使用后的密封圈表面损伤主要由3个原因造成:起源于机械损伤引起的密封圈过载开裂;由于压力过大形成挤压开裂,并在油压的循环作用下发生疲劳开裂;由载荷和环境共同作用引起的应力老化开裂。针对相应的损伤模式提出装配时注意密封件方向、改变密封圈安装槽结构、换用全氟醚橡胶密封圈等改进措施。

The O-shaped seal ring as the key component that plays a vital role in the safety work of the fuel accessory of the aero-engine.In this paper,the O-shaped seal rings used by aviation engine fuel accessories were subjected to macro and microscopic observation,FTIR,DSC and TGA analysis,and the fracture morphology and thermophysical properties between the same batch of unused and used seal rings were compared.The analysis results show that the surface damaging of seal ring by used 550 h is mainly due to the following three reasons.First of all,the seal ring overload cracking caused by mechanical damage.Secondly,due to excessive pressure to form extrusion cracking,and the fatigue cracking caused by cyclic action of oil pressure.Besides,stress aging cracking caused by the combined action of load and environment.According to the corresponding damage mode,it is proposed to pay attention to the direction of the seal,change the structure of the sealing ring installation slot,and replace the perflurane rubber seal ring during assembly.