双转子系统的振动

双转子结构广泛应用于现代航空发动机中。为了提高推重比,常将高压转子的后支点设计成轴间轴承(或称中介轴承)形式。常将转子设计成柔性转子,即在工作范围内,转子要越过一阶、二阶甚至三阶临界转速。这就使得发动机转子成为耦合很强的双转子系统,传统的单转子理论不能完全描述其振动特性。建立采用中介轴承的双转子模型,考虑支承刚度和阻尼的影响,运用解析方法分析双转子的振动特性,以揭示双转子的振动规律,解释实际运行中出现的现象。

The Vibration Features of a Twin Spool Rotor System

Twin spool rotor systems are widely used in modern aircraft engines.Between the high pressure(HP) rotor and the low pressure(LP) rotor in a twin spool rotor system,there is normally an inter-bearing supporting one end of the high pressure(HP) rotor.This structure can reduce the weight of the rotor system but make the coupling between the HP rotor and the LP rotor stronger.This paper sets up a simple model for simulating the vibration features of a twin spool rotor.The stiffness and damping of supports in the model are taken into account.The analytical results show that a twin spool rotor can easily exhibit a beat when the speed difference of HP rotor and LP rotor is small,say 10%.The magnitude of the beat can reach very high level at the critical speed.For keeping the vibration of a flexible rotor in an acceptable range,a high accuracy of rotor balancing is required.