转子系统瞬态热启动过程动力学特性研究

摘 要：某型航空发动机在停车后的冷却过程中，其高压转子会产生较大的热弯曲。当再次启动时，高压转子会产生较大的热振动，进而威胁到发动机的安全运行。采用流-热-固-动力学开放式半耦合系统，对停车后不同时刻的瞬态温度场对某航空发动机高压转子系统的瞬态热启动特性的影响进行了探讨并和试验值进行了比较。结果表明，高压转子的停车时间位于65~90min时，其转子的最大振速超过了最大临界安全振速80mm/s，因此，热启动时应当尽量避开这一时间段，或者在这一时间段冷运转后再启动减小热弯曲对瞬态振动的影响。计算结果为航空发动机高压转子系统的优化设计和热弯曲故障诊断提供了理论依据。

Dynamic characteristics of transient thermal starting up of a rotor system

Great thermal bending in an aeroengine, especially in high pressure (HP) rotor, is existing frequently in course of cooling after parking. When the rotor system starts up again, it brings relative big thermal vibrations which threaten the safe operation of the aeroengine. Here, the thermal vibration characteristics of a HP rotor system of a certain aeroengine were studied by means of the coupling theory of flow-thermal-structure-dynamics. The effect of temperature in different parking times on the dynamic characteristics of the HP rotor was discussed. At same time the calculated results were compared with experiment data. The results showed that during 65 ～90min of parking period, the maximum vibration velocity of the HP rotor exceeded the critical safe vibration velocity of 80mm/s. So when the rotor starts up after parking, it should avoid the period of 65 ～90min after parking to minish thermal vibration. Or after a cooling running, the rotor starts up again. The calculated results were references for design and fault diagnosis of HP rotors to avoid thermal vibra- tion.