温度场对航空发动机转子超转破裂的影响

CCAR33.27超转适航要求，分析和试验确定的超转转速，必须基于温度和温度梯度的最不利组合。因此，研究温度和温度梯度对超转破裂的影响有非常重要的意义。以某型航空发动机低压6级涡轮转子为例，采用极限应变方法开展了转子部件的超转破裂分析，对比了常温和高温（红线转速对应的温度分布）下转子关键轮盘应变分布趋势和应变增长规律、预测的超转破裂的起始位置和破裂转速等轮盘超转特性；针对超转破裂分析，提出了在高温条件下，经过常温超转破裂试验验证的方法应用的有效性条件。低压涡轮转子的分析结果也显示，红线转速对应的温度状态下，轮盘超转破裂转速比常温下显著降低，而高温下材料屈服强度的大幅降低则是破裂转速下降的主要原因。

Impacts of temperature fields on rotor over-speed fracture of aircraft engines

As required in CCAR33.27 airworthiness regulation, the determination of rotor burst rotating speeds using tests and analysis methods should consider the most adverse combination of temperature and temperature gradients. Therefore, to meet the requirements of CCAR 33.27, the impacts of temperature fields to rotor over-speed strength have to be evaluated accurately in aircraft engine design. As an example, this paper analyzes a low pressure turbine rotor with six stages of disks using the ultimate strain method. The results of temperature distribution related to the redline speed and room temperature conditions are compared in terms of deformation patterns and stain growth characters in the most critical disk, as well as predicted burst rotating speed and failure initiation location. Based on these comparisons, the validity criteria are proposed for rotor over-speed analysis methods applied to high temperature applications, which are validated by room temperature tests. The analyses show that at high temperature conditions related to the redline speed, the burst speed of the rotor is significantly lower than that under room temperature, and the lower burst speed at high temperature is mainly due to the substantially reduced yield strength of the materials.