水力机械运行中的拍振和共振问题探讨

Study on the issues of beat vibration and resonance in hydraulic machinery

拍振和共振是常见的自然现象,对水力机械稳定运行危害很大,但在对其研究中存在将二者混淆和对部分虚假拍振信号辨识不清等问题,需深入探讨。本文首先介绍了拍振波的基本原理,通过对几种特殊情况的分析说明了拍振波的拍振频率和幅值范围,并在分析拍振波本质特征、共振基本特征、扰动频率和固有频率差别的基础上进一步论述了拍振和共振的区别,提出了扰动频率和系统固有频率接近不会产生拍振、两个不同的扰动波即使频率相同也不可能产生共振等新见解;其次,本文还分析了采集信号不健全和高频载波两种虚假"类拍振波"的产生原因,提出了提高信号采集频率避免类拍振波和依据拍振波本质特征辨识拍振波的简单方法。

Beat vibration and resonance are common natural phenomena and they have great danger to the stable operation of turbine. But there is confusion about differences between beat vibration and resonance, and some false signals of beat vibration could not be recognized. It is necessary to study these issues and provide foundation for solving the unstable problems of turbine. The basic principle of beat vibration wave is introduced, and the frequency and amplitude of beat vibration are illustrated by analyzing several special cases. The basic features of beat vibration and resonance are analyzed as well as the differences of disturb- ing frequency and natural frequency. It is found that, resonance will not occur if the disturbing frequency is close to the natural frequency or if two different disturbing waves have the same frequency. Besides, un- sound collected signals and high frequency carrier wave could cause false beat vibration. The method of avoiding false beat vibration by increasing collecting frequency, as well as the method of recognizing and identifying the beat vibration wave according to its natural features, are given out.