風(fēng)機(jī)適用于各個(gè)生產(chǎn)行業(yè)，不論在哪個(gè)行業(yè)上用途都很廣泛性，但是在運(yùn)作中會產(chǎn)生一些噪音，噪音污染會對工作人員健康造成損害，所以離心風(fēng)機(jī)的降噪是不可缺少的，為大家總結(jié)了幾個(gè)有效的降噪方案可以給大家參考：
    Fan is suitable for various industries, no matter which industry is widely used, but it will produce some noise in operation, noise pollution will cause damage to the health of staff, so the noise reduction of centrifugal fan is indispensable.
    1、風(fēng)機(jī)降噪-合理的蝸舌間隙和蝸舌半徑fan noise reduction - reasonable tongue gap and tongue radius.
    當(dāng)氣流與葉片做相對運(yùn)動時(shí)，葉片后緣的氣流尾跡中速度及壓力均小于主流區(qū)，使葉柵后的氣流速度與壓力分布皆不均勻，這種不均勻的氣流在旋轉(zhuǎn)，由于在動葉的氣流出口有蝸舌存在，則這種非穩(wěn)定流動與蝸舌相互作用將產(chǎn)生噪聲， 距離噪聲愈近噪聲愈烈，通常適當(dāng)取較大的風(fēng)舌前端半徑可以降低離心風(fēng)機(jī)的旋轉(zhuǎn)噪聲與渦流噪聲。
    When the air flow is relative to the blade, the velocity and pressure in the airflow wake of the rear edge of the blade are less than the mainstream, and the airflow velocity and pressure distribution behind the cascade are not uniform. This uneven airflow is rotating, and the interaction between the unsteady flow and the tongue will produce the existence of the worm tongue at the outlet of the moving blade. When the noise is getting closer and closer to the noise, the rotating noise and vortex noise of the centrifugal fan can be reduced by properly selecting the front radius of the larger wind tongue.

    2、風(fēng)機(jī)降噪-蝸舌傾斜The noise reduction of the fan - the slanting of the tongue
    風(fēng)機(jī)葉輪葉柵氣流的周期性脈動速度所產(chǎn)生的周期性脈動氣動力也使蝸舌相互作用產(chǎn)生旋轉(zhuǎn)噪聲，此噪聲大小與脈動氣動力的劇烈程度及渦舌的迎風(fēng)面積有關(guān)，把蝸舌做成傾斜式，則同相位的脈動氣動力的作用面積小了，輻射的噪聲也就減小了。
    The periodic pulse kinetic aerodynamic force produced by the periodic pulsation velocity of the fan impeller blade cascade also causes the cochlea interaction to produce rotating noise, which is related to the intensity of the pulsating aerodynamic force and the windward area of the vortex tongue, and makes the worm tongue inclined, and the area of the pulse kinetic aerodynamic force at the same phase is smaller. The noise is also reduced.
    3、風(fēng)機(jī)降噪—采用消聲隔聲箱fan noise reduction - the use of noise reduction and sound insulation box
    控制風(fēng)機(jī)噪聲的常用方法是在風(fēng)機(jī)的進(jìn)、出口處安裝阻性消聲器。對于有更高降噪要求的場合，可以采用消聲隔聲箱，并在機(jī)組與地基之間安置減震器。
    The common way to control fan noise is to install a resistive silencer at the inlet and outlet of the fan. For occasions with higher noise reduction requirements, noise elimination and sound isolation boxes can be used, and shock absorbers should be installed between the units and the foundation.
    對于風(fēng)機(jī)采用強(qiáng)前向葉片，且多葉片葉輪有利于增大葉柵的氣動力載荷，在得到同樣風(fēng)量風(fēng)壓情況下，葉輪葉片外圓上圓周速度可使風(fēng)機(jī)噪聲明顯降低。
    For the wind turbine with the strong forward blade, and the multi blade impeller is beneficial to increase the aerodynamic load of the cascade. Under the same wind pressure condition, the circular velocity of the outer circle of the impeller blade can reduce the fan noise obviously.
    4、風(fēng)機(jī)降噪—葉輪入(出)口處加紊流化裝置Fan noise reduction - add turbulence device to impeller.
    在風(fēng)機(jī)葉輪葉片的入口或出口處加紊流化裝置(金屬網(wǎng))可以使葉片背面的層流附面層立即轉(zhuǎn)換成紊流附面層， 推遲葉片背面附面層的分離，甚不分離， 葉片后緣裝上網(wǎng)，網(wǎng)后的氣流速度與壓力梯度能迅速變均勻，若網(wǎng)在渦區(qū)中則可將渦區(qū)大大縮小,可進(jìn)一步減噪.
    A turbulent flow device (metal mesh) is added at the entrance or exit of the blade of the fan. The laminar laminar layer on the back of the blade can be converted into a turbulent boundary layer immediately. The separation of the surface layer on the back of the blade is postponed or even separated. The back edge of the blade is not separated. The flow velocity of the blade and the pressure gradient can be quickly uniform, if the net is in the vortex area. In addition, the vortex region can be greatly reduced and the noise reduction can be further reduced.
    5、風(fēng)機(jī)降噪—在蝸舌處設(shè)置聲學(xué)共振器Fan noise reduction - acoustic resonators installed at the tongue of the worm.
    蝸舌處設(shè)置聲學(xué)共振器，當(dāng)聲波傳到共振器時(shí)，小孔孔徑和空腔中的氣體存聲波作用下來回運(yùn)動，這運(yùn)動的氣體具有一定的質(zhì)量，它抗拒由于聲波作用而引起的運(yùn)動，同時(shí)聲波進(jìn)入小孔孔徑時(shí)，由于頸壁的摩擦和阻尼，使相當(dāng)一部分聲能因熱耗而損失掉。另外充滿氣體的空腔具有阻礙來自小孔的壓力變化的特性，由于這些因素的共同作用，當(dāng)氣體通過共振器時(shí)，噪聲得到了降低。
    The acoustic resonator is set up at the tongue of the worm. When the acoustic wave is transmitted to the resonator, the aperture of the hole and the gas in the cavity are played down and back to motion. The gas of the motion has a certain mass. It resists the motion caused by the sound wave action. At the same time, when the sound wave enters the aperture of the hole, it is equivalent to the friction and damping of the neck wall. Some of the sound energy is lost because of heat consumption. In addition, the cavity filled with gas has the characteristics that obstruct the pressure change from the hole. Because of the common action of these factors, the noise is reduced when the gas passes through the resonator.

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