摘要
钛火是现代航空发动机的典型灾难性事故,高压压气机机匣等钛合金部件的局部加热是主要的着火源。本研究通过对钛合金等温加热、非等温线性加热以及非等温摩擦加热的着火过程进行模型计算,研究初始加热温度、加热速率、氧浓度和流速等环境因素对着火参数的影响规律,进而给出钛火阻燃设计的建议。结果表明:在等温加热过程中,当加热面温度为1941 K时,临界着火温度约为958 K,着火延迟时间为0.2 s;在非等温线性加热过程中,加热速率为28 K/s、58 K/s及100 K/s的着火延迟时间分别为1.5 s、1.1 s和0.9 s,而临界着火温度基本维持在950K,微凸体直径为16.5μm时,临界着火温度约为765 K,与文献报道的实验结果一致;在非等温摩擦加热过程中,接触应力为26.5 kPa,加热速率为130 K/s时,着火延迟时间为1.4 s,流速为300 m/s时,临界着火温度为1040 K,着火延迟时间为2.8 s,当气流中氧浓度为50%,临界着火温度为920 K时,着火延迟时间为1.5 s;设计防钛火结构时应考虑低速环境下的阻燃性能。
Titanium fire is a typical catastrophic failure of modern aero-engine.The local heating of titanium alloy in the high-pressure compressor is the main ignition source.In this study,the ignition process of aero-engine titanium alloy isothermal heating,non-isothermal linear heating and non-isothermal friction heating were modeled to study the influence of factors such as the initial heating temperature,heating rate,oxygen concentration and flow rate on the ignition parameters,and then the recommendations on the flame-retardant design of titanium fire were given.The results show that during the isothermal heating process,the critical ignition temperature is about 958 K.When the heating surface temperature is 1941 K,the ignition delay time is 0.2 s.In the non-isothermal linear heating process,the ignition delay time of the heating rate of 28 K/s,58 K/s and 100 K/s are 1.5 s,1.1s and 0.9 s respectively,and the critical ignition temperature is basically maintained at about 950 K;When the microconvex is 16.5μm,the critical ignition temperature is about 765 K,which is consistent with the experimental results reported in the literature.In the non-isothermal friction heating process,the ignition delay time decreases with the increase of contact stress.When the contact stress is 26.5 kPa,the heating rate is 130 K/s,and the ignition delay time is 1.4 s;When the flow rate is 300 m/s,the critical ignition temperature is 1040 K,and the ignition delay time is 2.8 s;When the oxygen concentration in the airflow is 50%,the critical ignition temperature is 920 K,and the ignition delay time is 1.5 s.The flame retardancy in low-speed environment should be considered when designing anti-titanium fire structures.
作者
梁贤烨
弭光宝
李培杰
黄旭
曹春晓
LIANG Xianye;MI Guangbao;LI Peijie;HUANG Xu;CAO Chunxiao(Titanium Alloys Research Institute,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;National Center of Novel Materials for International Research,Tsinghua University,Beijing 100084,China;Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys,Beijing 100095,China)
出处
《航空材料学报》
CAS
CSCD
北大核心
2021年第6期59-67,共9页
Journal of Aeronautical Materials
基金
国家科技重大专项(J2019-VIII-0003-0165
2017-VII-0012-0109)。
关键词
钛合金
着火模型
着火温度
着火延迟时间
阻燃
titanium alloy
ignition model
ignition temperature
ignition delay time
flame retardant
