火箭推进

以Jeffcott转子为对象,从理论上介绍了重力副临界现象。在转轴有限元模型及轴承支承刚度修正的基础上,对某大推力补燃循环液体火箭发动机涡轮泵转子的前两阶临界转速和振型进行了仿真分析。通过高速运行试验,借助重力副临界识别出了转子的前两阶临界转速,并与全转速运行的识别结果及仿真结果进行了对比,1、2阶临界转速识别结果误差分别小于4.74和6.74。结果表明,高速运行时角接触轴承滚动体接触状态的轻微变化会引起支承刚度及转子系统动态响应发生变化,导致转子的运行状态波动,因此难以通过全转速范围内的响应数据来精确识别转子的临界转速; 低速下滚动轴承—转子系统的运行稳定性较好,采用重力副临界方法通过低速下的运行数据进行转子临界转速的识别(尤其是1阶临界转速识别)具有足够的精度。

Taking the Jeffcott rotor system as the study object, the phenomenon of gravity subcriticality is introduced theoretically.On the basis of the finite element model of rotating shaft and the correction of bearing support stiffness, the first two critical speeds and modes of the turbo-pump of a large thrust liquid rocket engine with staged combustion cycle are simulated.Through the high speed operation test, the first two critical speeds of the rotor have been identified with the help of gravity subcriticality, and compared with the identification results and simulation results of full speed operation, the errors of the first-order and the second-order critical speed identification results were less than 4.74 and 6.74, respectively.The results show that the slight change of rolling body contacting state of angular contact bearing will change the bearing stiffness and the rotor system response at high speed, so it is difficult to accurately identify the critical speed from the response data in the full speed range.The running stability of the rolling bearing-rotor is good at low speed and the identification of rotor critical speed(especially the first-order critical speed identification)using the gravity subcritical method based on the data of low speed operation has a high accuracy.

引言
1 重力副临界
2 临界转速仿真分析
3 临界转速的运行识别
4 结论

图1 水平Jeffcott转子简图<br/>Fig.1 Schematic diagram of horizontal Jeffcott rotor

图1 水平Jeffcott转子简图
Fig.1 Schematic diagram of horizontal Jeffcott rotor

图2 圆盘的瞬时位置及其所受的力<br/>Fig.2 Instantaneous position of the disk and the forces acting on it

图2 圆盘的瞬时位置及其所受的力
Fig.2 Instantaneous position of the disk and the forces acting on it

图3 涡轮泵轴系示意图<br/>Fig.3 Schematic diagram of turbo-pump shafting

图3 涡轮泵轴系示意图
Fig.3 Schematic diagram of turbo-pump shafting

图4 涡轮泵转子自由模态试验<br/>Fig.4 Free mode test of turbo-pump rotor

图4 涡轮泵转子自由模态试验
Fig.4 Free mode test of turbo-pump rotor

表1 涡轮泵转子前两阶模态修正结果<br/>Tab.1 Correction results of the first two modes of turbo-pump rotor

表1 涡轮泵转子前两阶模态修正结果
Tab.1 Correction results of the first two modes of turbo-pump rotor

表2 刚性摆架前三阶模态修正结果<br/>Tab.2 Correction results of the first three modes of rigid pedestal

表2 刚性摆架前三阶模态修正结果
Tab.2 Correction results of the first three modes of rigid pedestal

图5 刚性摆架前三阶振型试验和仿真结果对比<br/>Fig.5 Comparison of experimental and simulating results of the first third vibration modes of rigid pedestal

图5 刚性摆架前三阶振型试验和仿真结果对比
Fig.5 Comparison of experimental and simulating results of the first third vibration modes of rigid pedestal

表3 涡轮泵转子前两阶临界转速分析结果<br/>Tab.3 Analysis results of the first two critical speeds of turbo-pump rotor

表3 涡轮泵转子前两阶临界转速分析结果
Tab.3 Analysis results of the first two critical speeds of turbo-pump rotor

图6 涡轮泵转子前两阶振型<br/>Fig.6 The first two mode shape of turbo-pump rotor

图6 涡轮泵转子前两阶振型
Fig.6 The first two mode shape of turbo-pump rotor

图7 涡轮泵转子运行现场示意图<br/>Fig.7 Schematic diagram of turbo-pump rotor operation

图7 涡轮泵转子运行现场示意图
Fig.7 Schematic diagram of turbo-pump rotor operation

图8 轴向力加载示意图<br/>Fig.8 Schematic diagram of axial force loading

图8 轴向力加载示意图
Fig.8 Schematic diagram of axial force loading

图9 0～25 000 r/min运行时涡轮泵转子振动位移变化曲线<br/>Fig.9 Variation curve of rotor vibration displacement during 0—25 000 r/min operation

图9 0～25 000 r/min运行时涡轮泵转子振动位移变化曲线
Fig.9 Variation curve of rotor vibration displacement during 0—25 000 r/min operation

图10 转子振动位移的2f曲线<br/>Fig.10 2f variation curve of rotor vibration displacement

图10 转子振动位移的2f曲线
Fig.10 2f variation curve of rotor vibration displacement

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备注

引言

1 重力副临界

2 临界转速仿真分析

3 临界转速的运行识别

4 结论

期刊信息