多叶片离心通风机气动噪声特性及其控制

对风机气动噪声的产生机理及影响因素进行了系统的理论分析：（１）分析计算了风机噪声频谱中突出的峰包噪声的产生机理及频率分布特性；（２）对连续语随机嗓声的产生机理进行了理论分析和计算机模拟验证；（３）计算出风机旋转噪声与风机结构及叶道流型之间的关系，分析结果为该类型风机的噪声控制提供了可靠的理论依据和明确的降噪原则．通过大量实验及优化，研制出一套独特的整流丝网和导流吸声相结合的离心风机降噪措施，使风机噪声Ａ声级由７７．２ｄＢ（Ａ）下降到７１．２ｄＢ（Ａ），全压损失为７．３％，风机比Ａ声级由１６．８ｄＢ（Ａ）下降到１１．５ｄＢ（Ａ）．

AIR-FLOW NOISE CHARACTER AND CONTROL FOR CENTRIFUGAL FAN

Mechanisms of the air-flow noise generation process of the centrifugal fans are studiedsystematically. The theoretical work includes:(1)calculation and analysis of the significanttones in the A-weight noise spectrum,(2)theoretical study and computational simulation ofmechanism of the random broadband noise generation process,(3)derivation and calculationof the influence of structure parameters and the channel profile in impeller on the basic rota-tory noise, Results of the theoretical analyses provide reliable theory fdundation and guide-lines for noise control.A set of unique measures which combine transition meshes at theleading edges of impeller blades with flow leading noise absorption are developed through ex-periments and optimum design. As the results, the overall A-weight noise level of the experi-mental fan is reduced from 77. 2dB(A)to 71. 2dB(A), the total pressure loss is only 7.3%,and average A-weight noise level its reduced from 16. 8dB(A) to 11. 5dB(A).