噪聲處理

　　Noise processing

　　燃?xì)獍l(fā)電機(jī)組由燃?xì)獍l(fā)動(dòng)機(jī)、發(fā)電機(jī)、控制柜等部件組成,燃?xì)獍l(fā)動(dòng)機(jī)與發(fā)電機(jī)安裝在同一個(gè)鋼制底盤上。機(jī)組以天然氣、井口伴生氣、煤礦瓦斯氣、水煤氣、煉化尾氣、沼氣、焦?fàn)t煤氣、高爐煤氣等可燃性氣體為燃料,啟動(dòng)迅速,經(jīng)濟(jì)性好,特別是由于高質(zhì)量城市生活的需求,燃?xì)獍l(fā)電機(jī)組已廣泛應(yīng)用于電信、郵局、銀行、圖書館、醫(yī)院、賓館等部門,作為后備電源。最初燃?xì)獍l(fā)電機(jī)組是針對(duì)礦場(chǎng)工況設(shè)計(jì)的,機(jī)組運(yùn)行時(shí)產(chǎn)生的噪聲一般為95~110 dB(A)。GB 3096-93城市區(qū)域環(huán)境噪聲標(biāo)準(zhǔn)對(duì)市區(qū)的噪聲狀況進(jìn)行了嚴(yán)格的規(guī)定,對(duì)于2類區(qū)域(居住、商業(yè)、工業(yè)混雜區(qū))晝間為60 dB(A),夜間為50dB(A);對(duì)于1類區(qū)域(居住、文教機(jī)關(guān)區(qū))晝間為55 dB(A)、夜間為45 dB(A)。機(jī)組運(yùn)行時(shí)產(chǎn)生的噪聲給城市環(huán)境帶來(lái)了嚴(yán)重的噪聲污染,影響了人們的正常工作和生活,也限制了燃?xì)獍l(fā)電機(jī)組的廣泛應(yīng)用。本文就是針對(duì)燃?xì)獍l(fā)電機(jī)組噪聲污染問(wèn)題,提出了一套整改措施,以期降低機(jī)組噪聲,促進(jìn)燃?xì)獍l(fā)電機(jī)組的推廣應(yīng)用。

　　The gas generator set consists of gas engine, generator, control cabinet and other components. The gas engine and generator are installed on the same steel chassis. The unit is fueled by combustible gases such as natural gas, wellbore associated gas, coal mine gas, water gas, refining tail gas, biogas, coke oven gas, blast furnace gas, etc. It starts quickly and has good economy, especially due to the demand for high-quality urban life. Gas generator sets have been widely used in telecommunications, post offices, banks, libraries, hospitals, hotels and other departments as backup power sources. The initial gas generator set was designed for mining conditions, and the noise generated during operation is generally 95-110 dB (A). The GB 3096-93 Urban Regional Environmental Noise Standard strictly regulates the noise level in urban areas, with a daytime noise level of 60 dB (A) and a nighttime noise level of 50 dB (A) for Class 2 areas (residential, commercial, and industrial mixed areas); For Class 1 areas (residential, cultural and educational institutions), the daytime is 55 dB (A) and the nighttime is 45 dB (A). The noise generated during the operation of the unit has caused serious noise pollution to the urban environment, affecting people's normal work and life, and also limiting the widespread application of gas-fired power generation units. This article proposes a set of rectification measures to address the noise pollution problem of gas-fired power generation units, in order to reduce unit noise and promote the promotion and application of gas-fired power generation units.

　　1.聲源分析

　　1. Sound source analysis

　　燃?xì)獍l(fā)動(dòng)機(jī)噪聲是燃?xì)獍l(fā)電機(jī)組的主要噪聲來(lái)源,燃?xì)獍l(fā)動(dòng)機(jī)噪聲可分為空氣動(dòng)力噪聲、燃燒噪聲、機(jī)械噪聲、排氣噪聲和振動(dòng)噪聲?？諝鈩?dòng)力噪聲主要包括進(jìn)、排氣和風(fēng)扇旋轉(zhuǎn)引起的空氣振動(dòng)噪聲,這部分噪聲直接向空氣中傳播。氣缸內(nèi)燃燒所形成的壓力振動(dòng)通過(guò)缸蓋，機(jī)體向外輻射的噪聲叫燃燒噪聲;活塞對(duì)缸套的撞擊,配氣機(jī)構(gòu)、噴氣系統(tǒng)等運(yùn)動(dòng)部件產(chǎn)生的撞擊振動(dòng)噪聲統(tǒng)稱為機(jī)械噪聲。機(jī)組工作時(shí),廢氣從排氣門高速?zèng)_出,沿排氣歧管進(jìn)入消聲器,最后從尾管排入大氣。排氣噪聲是發(fā)動(dòng)機(jī)的最大噪聲,往往比發(fā)動(dòng)機(jī)主機(jī)噪聲高15 dB(A)左右,其次分別是燃燒噪聲和機(jī)械噪聲、風(fēng)扇噪聲、進(jìn)氣噪聲。

　　Gas engine noise is the main source of noise for gas generator sets. Gas engine noise can be divided into aerodynamic noise, combustion noise, mechanical noise, exhaust noise, and vibration noise. Aerodynamic noise mainly includes air vibration noise caused by intake, exhaust, and fan rotation, which directly propagates into the air. The pressure vibration formed by combustion inside the cylinder passes through the cylinder head, and the noise radiated outward from the body is called combustion noise; The impact of the piston on the cylinder liner, as well as the impact vibration noise generated by moving parts such as the valve train and jet system, are collectively referred to as mechanical noise. When the unit is working, exhaust gas rushes out of the exhaust valve at high speed, enters the muffler along the exhaust manifold, and finally is discharged into the atmosphere through the tailpipe. Exhaust noise is the maximum noise of the engine, often about 15 dB (A) higher than the noise of the engine host, followed by combustion noise and mechanical noise, fan noise, and intake noise.

　　2.改造設(shè)計(jì)

　　2. Renovation design

　　基于燃?xì)獍l(fā)電機(jī)組的工作原理,難以用降低聲源噪聲的方法來(lái)消聲,所以主要是要有效阻斷其噪聲傳播途徑。消聲技術(shù)的核心就是利用聲波在傳播中自然衰減的規(guī)律去縮小噪聲的污染面。具體降低噪聲的方法有以下幾種:吸聲、隔聲及改變?cè)肼晜鞑シ较?。在?shí)際工程應(yīng)用中往往只用其中一種,本文采用三種方法并用的措施,針對(duì)燃?xì)獍l(fā)電機(jī)組提出了新型組合降噪技術(shù)。

　　Based on the working principle of gas generator sets, it is difficult to use methods that reduce sound source noise to eliminate noise, so the main focus is to effectively block its noise propagation path. The core of noise reduction technology is to use the natural attenuation law of sound waves during propagation to reduce the pollution surface of noise. There are several specific methods to reduce noise, including sound absorption, sound insulation, and changing the direction of noise propagation. In practical engineering applications, only one of them is often used. This article proposes a new combination noise reduction technology for gas-fired generator sets by combining three methods.

　?。?）組合消聲器

　　(1) Combination muffler

　　原來(lái)的消聲器以阻性消聲為主,功耗大,消聲效果不理想。經(jīng)仔細(xì)論證,應(yīng)用三級(jí)組合降噪技術(shù),將消聲器改造為新型組合式消聲器。該組合式消聲器的主要組成部件有對(duì)噴消聲減振腔、多孔式消聲罩及吸聲隔熱層和吸聲共振板等。聲源通過(guò)第一級(jí)的對(duì)噴消聲減振腔,可將中低頻聲源的噪聲能量充分進(jìn)行抗性耗散。二級(jí)的多孔式阻性消聲罩可消去大部分高頻噪聲,增加了消聲器對(duì)高頻的適應(yīng)性,而且在該腔內(nèi)裝有高效吸聲材料,可對(duì)噪聲進(jìn)行充分的吸收和變向,從而最大限度地消耗噪聲能量。第三級(jí)為專門設(shè)計(jì)的帶共振板的排氣管,進(jìn)一步通過(guò)薄片的振動(dòng)進(jìn)行消聲。經(jīng)測(cè)試,新型消聲器的消聲量、消聲頻率范圍(主要為消聲量峰值的頻率范圍)及阻力損失三大指標(biāo)均優(yōu)于原來(lái)的消聲器。此外該消聲器尺寸適宜,結(jié)構(gòu)剛性好,安裝方便,并具有抑制再生噪聲的功能。而且后部的吸聲隔音層具有防腐性能,可有效地克服煙氣的低溫露點(diǎn)腐蝕,延長(zhǎng)了消聲器的使用壽命。

　　The original muffler mainly used resistive noise reduction, with high power consumption and unsatisfactory noise reduction effect. After careful demonstration, the application of three-level combined noise reduction technology has transformed the muffler into a new type of combined muffler. The main components of this combination muffler include a spray noise reduction and vibration reduction chamber, a porous noise reduction cover, a sound absorption and insulation layer, and a sound absorption resonance plate. The sound source can effectively dissipate the noise energy of the mid to low frequency sound source through the first stage of the anti spray noise reduction chamber. The secondary porous resistive muffler can eliminate most of the high-frequency noise, increasing the adaptability of the muffler to high frequencies. Moreover, high-efficiency sound-absorbing materials are installed in the cavity to fully absorb and redirect the noise, thereby maximizing the consumption of noise energy. The third level is a specially designed exhaust pipe with a resonant plate, which further reduces noise through the vibration of thin sheets. After testing, the three major indicators of the new muffler, including the noise reduction amount, noise reduction frequency range (mainly the frequency range of the peak noise reduction amount), and resistance loss, are all superior to the original muffler. In addition, the muffler has suitable size, good structural rigidity, easy installation, and the function of suppressing regenerative noise. Moreover, the sound-absorbing layer at the rear has anti-corrosion properties, which can effectively overcome the low-temperature dew point corrosion of smoke and extend the service life of the muffler.

　?。?）兩級(jí)隔振襯墊

　　(2) Two level isolation pad

　　控制機(jī)械噪聲和燃燒噪聲的有效辦法是對(duì)機(jī)組進(jìn)行隔振處理。燃?xì)鈾C(jī)、發(fā)電機(jī)與鋼制底盤間裝設(shè)復(fù)合隔振減振墊,底盤與基礎(chǔ)之間亦墊上高效減振膠墊。經(jīng)過(guò)兩級(jí)隔振處理,不僅使機(jī)組的振動(dòng)被有效隔斷,而且使機(jī)組運(yùn)行更加平穩(wěn),整體噪聲顯著降低。

　　The effective way to control mechanical noise and combustion noise is to isolate the unit. Composite vibration isolation and damping pads are installed between the gas turbine, generator, and steel chassis, and high-efficiency damping rubber pads are also placed between the chassis and the foundation. After two-stage vibration isolation treatment, not only is the vibration of the unit effectively isolated, but the operation of the unit is also smoother, and the overall noise is significantly reduced.

　　（3）消聲排風(fēng)道

　　(3) Silencing exhaust duct

　　風(fēng)扇噪聲是由旋轉(zhuǎn)噪聲和渦流噪聲組成。旋轉(zhuǎn)噪聲由旋轉(zhuǎn)風(fēng)扇葉片切割空氣流產(chǎn)生周期性擾動(dòng)而引起。渦流噪聲是在旋轉(zhuǎn)葉片截面上發(fā)生邊界層分離時(shí),氣體滑脫或分裂而成的一系列的漩渦流,從而輻射出一種非穩(wěn)定的流動(dòng)噪聲。排風(fēng)道直接與外界相通,空氣流速很大,氣流噪聲、風(fēng)扇噪聲和機(jī)械噪聲經(jīng)此通道輻射出去。為了控制風(fēng)扇和排風(fēng)通道的噪聲,設(shè)計(jì)了一個(gè)消音排風(fēng)道。這個(gè)消音排風(fēng)道長(zhǎng)度較大,由導(dǎo)風(fēng)槽和排風(fēng)降噪腔組成。排風(fēng)降噪腔的工作原理,類似于阻性消聲器?？赏ㄟ^(guò)更換吸音材料(改變材料的吸音系數(shù)),改變吸音材料厚度、排風(fēng)通道長(zhǎng)度和寬度等參數(shù)來(lái)提高消音效果。

　　Fan noise is composed of rotational noise and eddy current noise. Rotating noise is caused by periodic disturbances generated by the cutting of air flow by rotating fan blades. Eddy noise is a series of vortex flows formed by the detachment or splitting of gas during boundary layer separation on a rotating blade section, which radiates an unstable flow noise. The exhaust duct is directly connected to the outside world, and the air flow velocity is high. The airflow noise, fan noise, and mechanical noise are radiated out through this channel. In order to control the noise of the fan and exhaust duct, a soundproof exhaust duct was designed. This soundproof exhaust duct has a relatively long length and is composed of air ducts and exhaust noise reduction chambers. The working principle of the exhaust noise reduction chamber is similar to that of a resistive muffler. The sound-absorbing effect can be improved by replacing the sound-absorbing material (changing the sound-absorbing coefficient of the material), changing the thickness of the sound-absorbing material, the length and width of the exhaust duct, and other parameters.

　?。?）消聲進(jìn)氣道

　　(4) Silencing intake duct

　　機(jī)組工作在封閉的機(jī)房里面,從廣義上講,進(jìn)氣系統(tǒng)包括機(jī)組的進(jìn)風(fēng)通道和發(fā)動(dòng)機(jī)的進(jìn)氣系統(tǒng)。進(jìn)風(fēng)通道和排風(fēng)通道一樣直接與外界相通,空氣的流速很大,氣流的噪聲和機(jī)組運(yùn)轉(zhuǎn)的噪聲都經(jīng)進(jìn)風(fēng)通道輻射到外面。發(fā)動(dòng)機(jī)進(jìn)氣系統(tǒng)的噪聲是由進(jìn)氣門周期性開、閉而產(chǎn)生的壓力波動(dòng)所形成,其噪聲頻率一般處于500Hz以下的低頻范圍。在機(jī)房墻上設(shè)置了兩個(gè)消聲進(jìn)氣道,分別作為機(jī)房的進(jìn)風(fēng)口和發(fā)動(dòng)機(jī)的進(jìn)氣口。由于排風(fēng)造成的室內(nèi)負(fù)壓,使冷空氣自然通過(guò)消聲進(jìn)氣道進(jìn)入機(jī)房?jī)?nèi),將機(jī)體散發(fā)的熱量順利排出。從而保證了機(jī)房?jī)?nèi)有足夠的新鮮空氣。

　　The crew works in a closed computer room, and in a broad sense, the intake system includes the intake duct of the crew and the intake system of the engine. The inlet duct, like the exhaust duct, is directly connected to the outside world. The air flow velocity is high, and the noise of the airflow and the operation of the unit are radiated to the outside through the inlet duct. The noise of the engine intake system is formed by pressure fluctuations caused by the periodic opening and closing of the intake valve, and its noise frequency is generally in the low frequency range below 500Hz. Two soundproof air intakes have been installed on the wall of the computer room, serving as the air inlet for the computer room and the engine. Due to the negative pressure caused by exhaust, cold air naturally enters the computer room through the soundproof intake duct, smoothly dissipating the heat emitted by the machine body. This ensures that there is sufficient fresh air in the computer room.

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