阻燃钛合金摩擦着火热源模型及仿真分析

钛火是现代航空发动机的典型灾难性事故,压气机转子与静子的异常摩擦是其主要热源。采用动网格方法结合等效模型建立转子与静子试件的三维热-力-磨损耦合有限元模型,对不同摩擦接触压力和环境温度等条件下550℃阻燃钛合金TF550摩擦着火过程的温度场进行数值建模与仿真分析。结果表明,在室温、200 N摩擦接触压力条件下,TF550钛合金静子试件在7.2 s达到着火温度,此时转子试件温度仍维持在1 000 K,比静子试件低约900 K;当摩擦接触压力从200 N增大至400 N时,摩擦着火延迟时间为3.3 s;当摩擦接触压力提升至700 N时,着火延迟时间缩短至2 s以内;在823 K的环境温度下,静子试件的摩擦着火延迟时间为5 s,比室温下的摩擦着火延迟时间缩短了2.2 s;相对于环境温度的影响,摩擦接触压力对TF550钛合金摩擦着火升温速率的影响更大。

Numerical Model and Analysis of Friction Ignition Process of Fireproof Titanium Alloy

Titanium fire is a typical catastrophic failure of modern aeroengine. Abnormal friction between compressor rotor and stator is the main heat source. A three-dimensional thermo-mechanical-wear coupled finite element model of rotor/stator specimens was established by dynamic mesh method combined with equivalent model. The temperature field of the friction ignition process of fireproof titanium alloy under different friction contact pressures and temperatures was numerically modeled and simulated. The results show that the maximum temperature of the rotor specimen is lower than that of the stator specimen. Under 200 N friction contact pressure and room temperature boundary conditions, it cost 7.2 s to reach the ignition temperature of the TF550 fireproof titanium alloy stator specimen. At the same time, the temperature of the rotor specimen remains around 1 000 K while the temperature of the stator specimen remains around 1 900 K; when the friction contact pressure increases from 200 N to 400 N, the ignition delay time reduce to 3.3 s. When the friction contact pressure rises to 700 N, the ignition delay time decreases to less than 2 s; at 823 K ambient temperature, the ignition delay time of stator is 5 s, which is 2.2 s shorter than that of room temperature; relative to the influence of ambient temperature, the change of friction contact pressure has a greater impact on the heating rate.