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为了掌握声腔对燃烧室声学特性的影响规律,采用冷态实验方法,研究了带有轴向直圆孔声腔的模拟燃烧室的声学特性,其中声腔长度、开口面积比(声腔横截面积除以燃烧室横截面积)和个数均可调节.研究结果表明:燃烧室固有频率随声腔长度的增加而逐渐减小;声腔存在最佳深度,能够抑制一阶切向振型,该最佳深度不受声腔开口面积比影响,略小于1/4一阶切向波长;对抑制一阶切向振型而言,声腔存在最佳开口面积比,在本研究中约为0.17;声腔的分布对燃烧室的声学特性影响较大,相同开口面积比下,声腔个数越多,声波衰减越快.
In order to grasp the influence law of the acoustic cavity on the acoustic characteristics of the combustion chamber, the acoustic characteristics of the simulated combustion chamber with the axial straight circular hole acoustic cavity were studied by using the cold experimental method. The acoustic cavity length, the ratio of the opening area The cross-sectional area of the combustion chamber and the number of the combustion chamber can be adjusted.The results show that the natural frequency of the combustion chamber decreases with the increase of the length of the acoustic cavity, the optimal depth of the acoustic cavity can suppress the first-order tangential vibration mode, Which is slightly less than 1/4 first-order tangential wavelength, regardless of the opening area ratio of the sound cavity. For suppressing the first-order tangential vibration mode, the optimal opening area ratio exists in the sound cavity, which is about 0.17 in this study. Acoustic characteristics of the combustion chamber, the same opening area ratio, the more the number of acoustic cavity, the faster the attenuation of sound waves.