火箭推进

以25 tf级膨胀循环氢氧发动机氢涡轮泵为研究对象,针对超高转速氢涡轮泵柔性转子临界转速设计、稳定性控制的难题,采用有限元方法建立转子轴承系统动力学模型,考虑支承结构参与振动、密封流体的刚度及阻尼、支承刚度及阻尼随转速变化等因素的影响,计算分析了设计参数对转子临界转速、稳定性的影响,提出了优化改进方向。仿真分析表明:该氢涡轮泵的转子系统设计方案能够满足临界转速裕度、弯曲应变能控制的设计准则和目标要求; 工作转速范围内转子一阶对数衰减率最小值约为0.15,满足稳定性设计准则的最低要求; 若要进一步提高转子的稳定性裕度,可适当降低泵端弹性支承刚度,把转子悬臂段的流体密封由齿型结构改为阻尼更大的孔型结构,将对数衰减率提高到0.22以上。

This paper concerns the design of rotor dynamic characteristics of an ultrahigh speed hydrogen turbopump for a 25 tf expander cycle engine.The dynamic model of the rotor-bearing system was established using finite element method.The influence of design parameters on the critical speeds and stability of the rotor was calculated and analyzed, considering the effects of vibration of supporting structure, fluid forces of seals and variation of supporting stiffness and damping coefficients with rotational speed, etc.Some improvement measures for the rotor system were put forward.The results show that the presented design scheme of the turbopump rotor system can meet the rotor critical speed and bending strain energy rate design criteria, and the initial design objectives.The minimum first-order logarithmic decrement of the rotor in the working speed range is about 0.15, which achieves the minimum standard for rotor stability design criteria.According to the test experiences of other turbopumps, measures should be taken to increase the logarithmic decrements to more than 0.22.It is suggested that the stiffness of the elastic supporter at the pump end should be weakened properly, and the fluid seals in the cantilever section of the rotor should be redesigned from a tooth-shaped structure to a more damped orifice structure, so as to further improve the stability margin of the rotor.

引言
1 转子总体方案
3 稳定性计算分析
4 结论

图1 氢涡轮泵转子系统<br/>Fig.1 Rotor system of the hydrogen turbopump

图1 氢涡轮泵转子系统
Fig.1 Rotor system of the hydrogen turbopump

图2 支承结构参振模型示意图<br/>Fig.2 Schematic diagram of supporting structure vibration model

图2 支承结构参振模型示意图
Fig.2 Schematic diagram of supporting structure vibration model

图3 转子系统有限单元模型<br/>Fig.3 Finite element model of the rotor system

图3 转子系统有限单元模型
Fig.3 Finite element model of the rotor system

表1 基准状态转子临界转速和弯曲应变能<br/>Tab.1 Critical speeds and bend strain energy rates of the reference state rotor

表1 基准状态转子临界转速和弯曲应变能
Tab.1 Critical speeds and bend strain energy rates of the reference state rotor

图4 基准状态转子前三阶模态振型<br/>Fig.4 First three mode shapes of the reference state rotor

图4 基准状态转子前三阶模态振型
Fig.4 First three mode shapes of the reference state rotor

图5 支承刚度对转子临界转速的影响<br/>Fig.5 Effect of supporting stiffness on rotor critical speeds

图5 支承刚度对转子临界转速的影响
Fig.5 Effect of supporting stiffness on rotor critical speeds

表2 额定转速下密封流体对转子的附加刚度及阻尼<br/>Tab.2 Additional stiffness and damping from seal fluid at rated speed

表2 额定转速下密封流体对转子的附加刚度及阻尼
Tab.2 Additional stiffness and damping from seal fluid at rated speed

表3 考虑密封流体附加刚度及阻尼的临界转速<br/>Tab.3 Critical speeds considering the effect of additional stiffness and damping from seal fluid

表3 考虑密封流体附加刚度及阻尼的临界转速
Tab.3 Critical speeds considering the effect of additional stiffness and damping from seal fluid

图6 轮盘质量变化对转子临界转速的影响<br/>Fig.6 Effect of blade disk mass variation on rotor critical speeds

图6 轮盘质量变化对转子临界转速的影响
Fig.6 Effect of blade disk mass variation on rotor critical speeds

图7 外阻尼为0时转子对数衰减率随转速的变化<br/>Fig.7 Variation of logarithmic decrement with rotational speed when external damping is zero

图7 外阻尼为0时转子对数衰减率随转速的变化
Fig.7 Variation of logarithmic decrement with rotational speed when external damping is zero

图8 增加金属橡胶阻尼器后转子对数衰减率随转速的变化<br/>Fig.8 Variation of logarithmic decrement with rotational speed when damper is added

图8 增加金属橡胶阻尼器后转子对数衰减率随转速的变化
Fig.8 Variation of logarithmic decrement with rotational speed when damper is added

表4 级间密封改进前后刚度及阻尼系数对比<br/>Tab.4 Comparison of stiffness and damping between before and after seal improvement

表4 级间密封改进前后刚度及阻尼系数对比
Tab.4 Comparison of stiffness and damping between before and after seal improvement

图9 级间密封改进前后转子对数衰减率对比<br/>Fig.9 Comparison of rotor logarithmic decrement between before and after seal improvement

图9 级间密封改进前后转子对数衰减率对比
Fig.9 Comparison of rotor logarithmic decrement between before and after seal improvement

[1] 王小军.中国航天运输系统未来发展展望[J].导弹与航天运载技术, 2021(1):1-6.
[2] 岳文龙, 郑大勇, 颜勇, 等.我国高性能液氧液氢发动机技术发展概述[J].中国航天, 2021(10):20-25.
[3] 黄道琼, 王振, 杜大华.大推力液体火箭发动机中的动力学问题[J].中国科学(物理学力学天文学), 2019, 49(2):19-30.
[4] 夏德新.高压多级氢涡轮泵转子动力学设计与试验研究[J].导弹与航天运载技术, 2001(6):21-26.
[5] ALLIOT P, GOIRAND B, MARCHAL N.The VINCI hydrogen turbopump development status[C]//38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit.Reston, Virginia:AIAA, 2002.
[6] OOTA T, KIMOTO K, KAWAI T, et al.Design, fabrication and test of the RL60 fuel turbopump[C]//39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit.Reston, Virginia:AIAA, 2003.
[7] RACHUK V, TITKOV N.The first Russian LOX-LH2 expander cycle LRE:RD0146[C]//42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit.Reston, Virginia:AIAA, 2006.
[8] 窦唯, 褚宝鑫.支承总刚度对涡轮泵转子临界转速及稳定性的影响[J].火箭推进, 2014, 40(1):30-38.
[9] 廖明夫.航空发动机转子动力学[M].西安:西北工业大学出版社, 2015.
[10] 金路, 王俨剀, 王彤, 等.涡轮泵转子失稳故障分析[J].火箭推进, 2020, 46(4):23-30.
[11] 冀沛尧, 何立东, 胡航领, 等.涡轮泵密封对转子动力特性的影响[J].润滑与密封, 2019, 44(1):52-57.
[12] 白长青, 许庆余, 张小龙.密封和内阻尼对火箭发动机液氢涡轮泵转子系统动力稳定性的影响[J].机械工程学报, 2006, 42(3):150-155.
[13] 窦唯, 叶志明, 闫宇龙.涡轮泵叶轮/转子配合间隙对稳定性的影响[J].火箭推进, 2016, 42(4):26-34.
[14] BAI C Q, XU Q Y, WANG J Y.Effects of flexible support stiffness on the nonlinear dynamic characteristics and stability of a turbopump rotor system[J].Nonlinear Dynamics, 2011, 64(3):237-252.
[15] 罗巧军, 褚宝鑫, 须村.氢涡轮泵次同步振动问题的试验研究[J].火箭推进, 2014, 40(5):14-19.
[16] OKAYASU A, OHTA T, AZUMA T, et al.Vibration problem in the LE-7 liquid hydrogen turbopump[C]//26th AIAA/SAE/ASME/ASEE Joint Propulsion Conference.Reston, Virginia:AIAA, 1990.
[17] MATTHEW C E.Solution of the sub-synchronous whirl problem in the high-pressure hydrogen turbopump of the space shuttle main engine[C]//14th AIAA/SAE Joint Propulsion Conference.Reston, Virginia:AIAA, 1978.
[18] CHILDS D W.The space shuttle main engine high-pressure fuel turbopump rotordynamic instability problem[J].Journal of Engineering for Power, 1978, 100(1):48-57.
[19] 崔荣军, 何伟锋.25吨级膨胀循环发动机技术方案研究[J].导弹与航天运载技术, 2015(6):21-24.
[20] 李铭, 胡晓睿, 涂霆, 等.一种超高转速液氢涡轮泵柔性转子:CN 111828372 A[P].2020-10-27.
[21] 王正.转动机械的转子动力学设计[M].北京:清华大学出版社, 2015.
[22] ERTAS B H, AL-KHATEEB E, VANCE J M.Rotordynamic bearing dampers for cryogenic rocket engine turbopumps[J].Journal of Propulsion and Power, 2003, 19(4):674-682.

备注

引言

1 转子总体方案

3 稳定性计算分析

4 结论

期刊信息