离心力场作用下的燃气轮机压气机叶片振动模态分析

 杨博宇,殷鸣,向召伟,殷国富

(四川大学 制造科学与工程学院,四川 成都 610065)
摘要:分析燃气轮机压气机叶片在离心力场作用下导致的动频相较于无载荷时的固有频率(静频)不同之处,求出叶片工作时的真实振型和共振频率对于提高叶片的动态性能有重要的作用。通过对某重型燃气轮机轴流式压气机某级动叶片的数字化建模和振动模态分析,分别计算得出了压气机叶片在无载荷、离心力场作用下的前六阶固有频率、动频及振型云图,分析了离心力场作用下叶片的应力分布状态,以及离心力场对叶片固有频率的影响。根据转子转速区间,分析了三种不同转速产生的离心力场对叶片频率的影响趋势。计算结果表明:离心力场使叶片产生动力刚化效应,使叶片的各阶动频相较固有频率有所增大;离心力场对基频影响最为显著,当转子转速为6000 r/min时,基频相对偏差达63.73%;动力刚化效应与转子转速呈正相关,叶片转速增大导致动频增大,且基频增大最为显著。
关键词:燃气轮机;压气机叶片;离心力场;模态分析;动频
中图分类号:TH113.1 文献标志码:A doi:10.3969/j.issn.1006-0316.2018.11.008
文章编号:1006-0316 (2018) 11-0031-06
The Vibration Modal Analysis of Compressor Blades of Gas Turbines under the Influence of Centrifugal Force Fields
YANG Boyu,YIN Ming,XIANG Zhaowei,YIN Guofu
( School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065, China )
Abstract:The calculation of mode shapes and resonant frequencies of compressor blades of gas turbines in working conditions, as well as the analysis of differences between the dynamic frequencies under the influence of centrifugal force fields and the natural frequencies (static frequencies ) of compressor blades, plays an important role in improving the blades' dynamic properties. In this paper, the vibrational frequencies and mode shapes of compressor blades from 1st to 6th order in load free and centrifugal force fields conditions are calculated separately by digital modeling and vibration modal analysis for moving blades of a certain axial-flow compressor of a heavy-duty gas turbine. The stress distribution as well as the natural frequencies of blades under the influence of centrifugal force fields is analyzed. The effect trends caused by centrifugal force fields which are generated in three different rotational velocities for blades' vibrational frequencies are analyzed. The result shows that: Centrifugal force fields cause the dynamic stiffening for blades which makes their dynamic frequency greater than the natural one in each order; Centrifugal force fields have the most significant impact on the fundamental frequencies of blades, for instance, when the blade's rotational velocity reaches 6000rpm, its relative deviation about fundamental frequency can achieve 63.73%; The dynamic stiffening is positively correlated with the blades' rotational velocities, and the greater rotational velocity causes the greater dynamic frequency, especially in the fundamental frequencies of blades.
Key words:gas turbine;compressor blade;centrifugal force field;modal analysis;dynamic frequency
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收稿日期:2018-01-09
基金项目:四川省科技支持计划项目(2016GZ0001);中央高校基本科研业务费专项资金资助(2015CDDY-S08-SCU)
作者简介:杨博宇(1988-),男,辽宁抚顺人,硕士研究生,助理工程师,主要研究方向为叶片增材制造、熔模铸造、模态分析;殷国富(1956-),男,四川西充人,教授,博士生导师,主要研究方向为制造自动化、智能设计技术、CAD/CAM/CIMS。
 

 

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