DEVELOPMENT OF NOISE REDUCTION METHOD FOR GRAIN DRYERS

烘干机周围的噪音为43分，乡村电梯为23分。在实验室测试中，我们使用FFT分析仪对测点使用反声前后的声音频率进行了分析。我们选取了7个样本，分别在噪声源周围0、45、90、135、180度角和扬声器反向噪声源周围1.5、5m、3.0m的距离上进行了FFT测量和分析。结果表明，通过反向噪声产生，噪声水平降低约10 ~ 20 dB。在排风管中安装一个扬声器，将空气干燥后产生的反向噪声实际上降低了约2db的排气噪声。研究了反向噪声消噪的模拟方法，利用实测噪声源记录得到了与现场实验结果相似的消噪特性。仿真结果也提示了一些有效的噪声控制方法。

The noize of 43 points around a unit dryer and 23 points in a country elevator were recorded.In the laboratory tests we used FFT analyzer to analyze the frequence of sound before and after using reverse sound for the measuring points. we took seven samples, the 0,45,90,135 and 180 degrees of angle and the distance of 1,5m and 3.0m around the noise source and the reversed noise source of the speaker were measured and analyzed by the FFT.The results indicated from about 10 (dB) to 20 (dB) reduction of noize level by the reversed noise generation. The reversed noise by a speaker in the exhaust duct for dryng air actually reduced the exhaust noise by about 2 dB.The similation of noize cancelation by reversed noise were developed, and using the recorded measured noise source the noise reduction characteristics similar to the preseding experimental results were obtained. The simulation was also suggestive of some effective method of noise control.