利用单传声器分解和测量管道内的高次模式声波

Higher-order Modes Decomposition and Measurement in Ducts Using Single Microphone

摘要:

利用数字声源信号可完全重复的特点，提出了通过单传声器对管道高次模式声波进行分解和测量的方法。与以前的研究相比较，此方法的主要特点是：只需在管道中使用单个传声器进行单次测量，避免了多传声器之间的相位匹配问题，并且极大地提升了可分解的高次模式数量。阐述了此模式分解方法的基本原理，建立了相应的测试系统；通过实验测量，与传统的驻波管法相比较，验证了此方法的有效性；最后，给出了一个典型的实验应用，对于口径为600mm的方形管道，在500Hz、1000Hz和2000Hz时，对管中存在的高次传播模式进行测量和分解。

Abstract:

A new method for decomposing and measuring higher-order mode waves in ducts using single microphone is proposed in this paper. The method is based on a repeatable inspiriting sound source associated with a slowly moving microphone along central axis of the duct. Compared with previous research, some problems such as microphone matching can be avoided, and much more modes can be obtained. At first the basic principle of modes decomposition, as well as single-microphone measurement system is described. Then the effectiveness of this method is verified by comparing the test results with those of the standard measurement in standing wave tube. Finally some experimental studies in a 600mm square waveguide are discussed.