Active source cancellation of the blade tone fundamental and harmonics in centrifugal fans
Active source cancellation of the blade tone fundamental and harmonics in centrifugal fans
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DOI：
10.1016/0022-460x(88)90236-2
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发表时间：
1988-10
影响因子：
4.7
通讯作者：
G. Koopmann;D. J. Fox;W. Neise
中科院分区：
文献类型：
--
作者：
G. Koopmann;D. J. Fox;W. Neise
在之前的论文中已经表明，离心式风扇的气动噪声可以通过主动源消除方法来控制。特别是，通过替换风扇截止部分来实现风扇叶片基音的消除，在该截止部分中，用两个适当驱动的辅助源生成空气动力学叶片音调。在本组实验中，该方法被扩展为包括消除叶片音调的谐波。还检查了一种特殊情况，其中叶片谐波的频率恰好高于风扇管道的第一高阶模式的截止频率。结果表明，主动控制对于叶片音调的谐波以及各种风扇负载条件和管道终端的基本原理是有效的。通过对风扇辐射声音的全局测量还获得了进一步的证据，支持主动控制机制涉及空气动力源压力的局部改变的想法。
In previous papers it has been shown that the aerodynamic noise of centrifugal fans can be controlled with active source cancellation methods. In particular, cancellation of a fan's blade tone fundamental was achieved by replacing a section of the fan's cut-off where the aerodynamic blade tones are generated with two appropriately driven secondary sources. In the present set of experiments, the method is extended to include cancellation of the harmonics of the blade tone. A special case is also examined where the frequency of the blade tone harmonic lies just above the cut-on frequency of the first higher order mode of the fan ducting. Results indicate that active control is effective at the harmonics of the blade tones as well as the fundamental for a variety of fan loading conditions and duct terminations. Further evidence has also been obtained with global measurements of the fan's radiated sound that supports the idea that the active control mechanism involves a local alteration of the aerodynamic source pressures.