工業風機噪音來源有哪些

　　一般工業風機的噪音在60-90分貝之間!而《城市區域噪聲標準》中規定了，工業區噪音大于55分貝的即視為噪音擾民!因此，很多工廠在采購工業風機或安裝工業風機時，都要考慮如何來降低工業風機的噪音!今天，我們一起分析一下工業風機噪音的來源有哪些!根據我們生產制造風機的經驗，空氣動力噪聲是工業風機噪聲中*強的，其次是機械噪聲和電磁噪聲。空氣動力噪聲包括旋轉噪聲、渦流噪聲和共振噪聲。分析表明，軸流風機的噪聲峰值存在于低頻階段，而中高頻階段則隨頻率的增加而降低。大氣吸收的噪音低于100Hz時，低頻噪聲的自然衰減非常緩慢。此外，低頻噪聲波段越長，障礙物繞射能力越強，風聲傳播距離越遠，污染范圍越大。

　　旋轉噪聲：又稱葉片噪聲，是由于葉片旋轉周期性打擊空氣質量點，導致空氣壓力脈動，其壓力尺寸與速度和葉片數量有關。旋轉葉片與靜止支架等構件之間的相對運動也會引起空氣脈動和噪聲。如果葉片數與支架數相同，則可能發生同期擾動，使壓力波動疊加，噪聲增加。為避免這種現象，可采用支架數與葉片數不等或不等節距的方法。

　　葉片與固定支架之間的距離也直接影響旋轉噪聲的聲功率，葉片頂部與風管殼體之間的距離。就單片而言，是周期性變化;就多片而言，間距不能一致。因此，在此間隙中，氣流脈動是周期性的和不規則的，因此噪聲大小與塔的制造質量和葉片安裝精度密切相關。

　　渦流噪聲：又稱湍流噪聲，是由于葉片旋轉時周圍氣流的邊界分離。渦流*容易在葉片背面形成，產生氣流呼嘯聲。為了降低噪音，葉片需要適當的寬度和流線型形狀。渦流噪聲的頻率取決于葉片和氣流之間的相對速度。葉輪旋轉時，葉片周圍的周轉速度隨軸距而變化，葉根到葉頂氣流的相對速度也不斷變化，因此渦流噪聲明顯具有連續頻譜的特點。

　　共振噪聲：由旋轉噪聲和渦流噪聲引起的噪聲。在設計中，應注意風管與工業風機外殼的內接縫應平整，避免因粗糙不均勻而引起撕裂聲，有時在風管外覆蓋阻尼材料。

　　如何降低工業風機噪聲?

　　阻性消音裝置。

　　阻性消聲裝置采用吸聲材料消聲，吸聲材料按一定規律安裝在氣流管道內，形成阻性消聲裝置，可有效達到工業風機降噪的目的。適用于消除中高頻噪聲，多用于消除普通風機設備、燃氣輪機等氣體流量小的噪聲。例如：工業羅茨鼓風機出廠時便會標配消音器!

　　抗消音裝置。

　　抗性消聲裝置通過控制聲抗實現消聲，即連接氣流管截面積突變的管段或旁接共振腔，改變聲阻抗，使某些頻率的聲波反射、干擾、抵消聲阻抗突變截面，達到工業風機降噪的目的。適用于消除空壓機、內燃機、汽車排氣等高氣流條件下產生的中低頻噪聲。

　　阻抗復合消音裝置。

　　阻抗復合消音裝置可簡單地認為是前兩種消音器的組合。由于阻力和阻力消聲裝置具有不同的噪聲消聲頻段，經過一定的結構復合后，可以消除高、中、低頻噪聲。適用于鼓風機、大風洞、試車臺等領域的噪聲消除，可更好地降低工業風機的噪聲。在羅茨鼓風機中，常用的便是隔音房!

　　以上便是工業羅茨風機廠家上海瑞柘環保分析的工業風機噪音的來源與降低方法!希望可以幫您解決噪音煩惱!

　　What are the sources of industrial fan noise

　　Generally, the noise of industrial fans is between 60-90 DB! And the national "urban regional noise standard" stipulates that the noise in industrial areas greater than 55 dB is regarded as noise nuisance! Therefore, many factories should consider how to reduce the noise of industrial fans when purchasing or installing industrial fans! Today, let's analyze the sources of industrial fan noise! According to our experience in manufacturing fans, aerodynamic noise is the strongest among industrial fans, followed by mechanical noise and electromagnetic noise. Aerodynamic noise includes rotating noise, eddy current noise and resonance noise. The analysis shows that the noise peak of axial flow fan exists in the low-frequency stage, while the medium and high-frequency stage decreases with the increase of frequency. When the noise absorbed by the atmosphere is lower than 100Hz, the natural attenuation of low-frequency noise is very slow. In addition, the longer the low-frequency noise band, the stronger the diffraction ability of obstacles, the farther the wind sound propagation distance, and the larger the pollution range.

　　Rotating noise: also known as blade noise, it is because the blade rotation periodically hits the air quality point, resulting in air pressure pulsation. Its pressure size is related to the speed and the number of blades. The relative motion between rotating blades and stationary supports will also cause air pulsation and noise. If the number of blades is the same as the number of supports, synchronous disturbance may occur, resulting in superposition of pressure fluctuations and increased noise. In order to avoid this phenomenon, the method of unequal number of supports and blades or unequal pitch can be adopted.

　　The distance between the blade and the fixed support also directly affects the sound power of the rotating noise, and the distance between the blade top and the air duct shell. For a single chip, it changes periodically; For multiple pieces, the spacing cannot be completely consistent. Therefore, in this gap, the air flow pulsation is periodic and irregular, so the noise level is closely related to the manufacturing quality of the tower and the installation accuracy of blades.

　　Vortex noise: also known as turbulent noise, is due to the boundary separation of the surrounding air flow when the blade rotates. Vortices are most likely to form on the back of the blades, producing a whistling sound of air flow. In order to reduce noise, blades need appropriate width and streamlined shape. The frequency of vortex noise depends on the relative velocity between the blade and the air flow. When the impeller rotates, the turnover speed around the blade changes with the wheelbase, and the relative speed of the air flow from the blade root to the blade top also changes constantly, so the eddy current noise obviously has the characteristics of continuous spectrum.

　　Resonance noise: noise caused by rotating noise and eddy current noise. In the design, it should be noted that the inner joint between the air duct and the industrial fan shell should be flat to avoid tearing sound caused by uneven roughness. Sometimes, the air duct is covered with damping materials.

　　Manufacturers analyze how to quickly reduce the noise of industrial fans

　　How to reduce the noise of industrial fans?

　　Resistive silencing device.

　　The resistive silencing device adopts sound-absorbing materials for silencing, and the sound-absorbing materials are installed in the air duct according to a certain law to form a resistive silencing device, which can effectively achieve the purpose of noise reduction of industrial fans. It is applicable to the elimination of medium and high frequency noise, and is mostly used to eliminate the noise with small gas flow such as ordinary fan equipment and gas turbine. For example, the industrial roots blower will be equipped with a silencer as standard when it leaves the factory!

　　Anti silencing device.

　　The resistant silencing device realizes silencing by controlling the acoustic reactance, that is, connecting the pipe section with sudden change in the cross-sectional area of the air duct or connecting the resonant cavity by the side, changing the acoustic impedance, so that the sound waves of some frequencies can reflect, interfere, and counteract the sudden change in the cross-sectional area of the acoustic impedance, so as to achieve the purpose of noise reduction of industrial fans. It is suitable for eliminating the medium and low frequency noise generated under high airflow conditions such as air compressors, internal combustion engines, automobile exhaust, etc.

　　Impedance compound silencing device.

　　The impedance composite silencing device can be simply considered as the combination of the first two silencers. Because the resistance and resistance silencing devices have different noise silencing frequency bands, high, medium and low-frequency noises can be eliminated after a certain structural compound. It is suitable for noise elimination in blower, gale tunnel, test bench and other fields, and can better reduce the noise of industrial fans. In Roots blower, the commonly used is sound proof room!

　　The above is the source and reduction method of industrial fan noise analyzed by Shanghai Ruizhe environmental protection, an industrial Roots fan manufacturer! I hope I can help you solve your noise problems!