燃氣發(fā)電機組由燃氣發(fā)動機、發(fā)電機、控制柜等部件組成,燃氣發(fā)動機與發(fā)電機安裝在同一個鋼制底盤上。機組以天然氣、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,啟動迅速,經(jīng)濟性好,特別是由于高質(zhì)量城市生活的需求,燃氣發(fā)電機組已廣泛應(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。初燃氣發(fā)電機組是針對礦場工況設(shè)計的,機組運行時產(chǎn)生的噪聲一般為95~110 dB(A)。G
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, wellhead associated gas, coal mine gas, water gas, refining tail gas, biogas, coke oven gas, blast furnace gas, etc. It is quick to start and has good economy. Especially due to the demand of high-quality urban life, the gas generator unit has been widely used in telecommunications, post offices, banks, libraries, hospitals, hotels and other departments as a backup power supply. At first, the gas generator unit was designed for the mine conditions, and the noise generated by the unit during operation is generally 95~110 dB (A). G
B 3096-93城市區(qū)域環(huán)境噪聲標(biāo)準(zhǔn)對市區(qū)的噪聲狀況進行了嚴(yán)格的規(guī)定,對于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);對于1類區(qū)域(居住、文教機關(guān)區(qū))晝間為55 dB(A)、夜間為45 dB(A)。機組運行時產(chǎn)生的噪聲給城市環(huán)境帶來了嚴(yán)重的噪聲污染,影響了人們的正常工作和生活,也限制了燃氣發(fā)電機組的廣泛應(yīng)用。本文就是針對燃氣發(fā)電機組噪聲污染問題,提出了一套整改措施,以期降低機組噪聲,促進燃氣發(fā)電機組的推廣應(yīng)用。
B 3096-93 urban area environmental noise standard has strict regulations on the noise situation in the urban area. For Class 2 areas (residential, commercial and industrial mixed areas), it is 60 dB (A) in the daytime and 50 dB (A) at night; 55 dB (A) in the daytime and 45 dB (A) at night for Class 1 areas (residential, cultural and educational institutions). The noise generated by the unit operation has brought serious noise pollution to the urban environment, affected people's normal work and life, and also restricted the wide application of gas generator units. This paper proposes a set of rectification measures to reduce the noise pollution of gas generating units and promote the popularization and application of gas generating units.
1.聲源分析
1. Sound source analysis
燃氣發(fā)動機噪聲是燃氣發(fā)電機組的主要噪聲來源,燃氣發(fā)動機噪聲可分為空氣動力噪聲、燃燒噪聲、機械噪聲、排氣噪聲和振動噪聲?？諝鈩恿υ肼曋饕ㄟM、排氣和風(fēng)扇旋轉(zhuǎn)引起的空氣振動噪聲,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通過缸蓋，機體向外輻射的噪聲叫燃燒噪聲;活塞對缸套的撞擊,配氣機構(gòu)、噴氣系統(tǒng)等運動部件產(chǎn)生的撞擊振動噪聲統(tǒng)稱為機械噪聲。機組工作時,廢氣從排氣門高速沖出,沿排氣歧管進入消聲器,后從尾管排入大氣。排氣噪聲是發(fā)動機的大噪聲,往往比發(fā)動機主機噪聲高15 dB(A)左右,其次分別是燃燒噪聲和機械噪聲、風(fēng)扇噪聲、進氣噪聲。
The noise of gas engine is the main noise source of gas generator set. The noise of gas engine can be divided into aerodynamic noise, combustion noise, mechanical noise, exhaust noise and vibration noise. Aerodynamic noise mainly includes air vibration noise caused by air inlet, exhaust and fan rotation, and this part of noise spreads directly into the air. The pressure vibration generated by combustion in the cylinder passes through the cylinder head, and the noise radiated from the engine body is called combustion noise; The impact of the piston on the cylinder liner and the impact vibration noise generated by the moving parts such as the valve train and the jet system are collectively referred to as mechanical noise. When the unit is working, the exhaust gas rushes out of the exhaust valve at high speed, enters the muffler along the exhaust manifold, and finally discharges into the atmosphere from the tail pipe. Exhaust noise is the largest noise of the engine, which is usually about 15 dB (A) higher than the noise of the engine host, followed by combustion noise, mechanical noise, fan noise, and intake noise.
2.改造設(shè)計
2. Reconstruction design
基于燃氣發(fā)電機組的工作原理,難以用降低聲源噪聲的方法來消聲,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。
Based on the working principle of the gas generator set, it is difficult to reduce the noise of the sound source, so the main thing is to effectively block its noise transmission path. The core of noise elimination technology is to reduce the pollution surface of noise by using the law of natural attenuation of sound waves in transmission.
具體降低噪聲的方法有以下幾種:吸聲、隔聲及改變噪聲傳播方向。在實際工程應(yīng)用中往往只用其中一種,本文采用三種方法并用的措施,針對燃氣發(fā)電機組提出了新型組合降噪技術(shù)。

The specific methods to reduce noise are as follows: sound absorption, sound insulation and changing the direction of noise propagation. In practical engineering applications, only one of these methods is often used. In this paper, a new combined noise reduction technology is proposed for gas generator units by using three methods together.
（1）組合消聲器
(1) Combined muffler
原來的消聲器以阻性消聲為主,功耗大,消聲效果不理想。經(jīng)仔細論證,應(yīng)用三級組合降噪技術(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。聲源通過級的對噴消聲減振腔,可將中低頻聲源的噪聲能量充分進行抗性耗散。二級的多孔式阻性消聲罩可消去大部分高頻噪聲,增加了消聲器對高頻的適應(yīng)性,而且在該腔內(nèi)裝有高效吸聲材料,可對噪聲進行充分的吸收和變向,從而大限度地消耗噪聲能量。第三級為專門設(shè)計的帶共振板的排氣管,進一步通過薄片的振動進行消聲。
The original muffler is mainly based on resistive noise elimination, with high power consumption and poor noise elimination effect. After careful demonstration, the muffler is transformed into a new type of combined muffler by using the three-level combined noise reduction technology. The main components of the combined muffler are the anti-jet muffler damping cavity, the porous muffler cover, the sound absorption insulation layer and the sound absorption resonance plate. The sound source can fully dissipate the noise energy of the medium and low frequency sound sources through the first stage of the anti-noise cavity. The two-stage porous resistive muffler can eliminate most of the high-frequency noise, increase the adaptability of the muffler to the high-frequency, and install high-efficiency sound absorption materials in the cavity, which can fully absorb and change the direction of the noise, so as to maximize the consumption of noise energy. The third stage is the specially designed exhaust pipe with resonance plate, which is further silenced by the vibration of the sheet.
經(jīng)測試,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腐蝕,延長了消聲器的使用壽命。
According to the test, the new muffler is superior to the original muffler in terms of noise reduction, frequency range of noise reduction (mainly the frequency range of peak noise reduction) and resistance loss. In addition, the muffler has proper size, good structural rigidity, convenient installation and the function of suppressing regenerative noise. Moreover, the sound absorption and sound insulation layer at the rear has anti-corrosion performance, which can effectively overcome the low temperature dew point corrosion of flue gas and prolong the service life of muffler.
（2）兩級隔振襯墊
(2) Two-stage vibration isolation pad
控制機械噪聲和燃燒噪聲的有效辦法是對機組進行隔振處理。燃氣機、發(fā)電機與鋼制底盤間裝設(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)過兩級隔振處理,不僅使機組的振動被有效隔斷,而且使機組運行更加平穩(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 engine, generator and steel chassis, and high-efficiency damping rubber pads are also installed between the chassis and the foundation. After two-stage vibration isolation treatment, not only the vibration of the unit is effectively isolated, but also the operation of the unit is more stable and the overall noise is significantly reduced.
（3）消聲排風(fēng)道
(3) Anechoic 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,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)計了一個消音排風(fēng)道。這個消音排風(fēng)道長度較大,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^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)通道長度和寬度等參數(shù)來提高消音效果。
Fan noise is composed of rotating noise and eddy current noise. The rotating noise is caused by the periodic disturbance of the air flow cut by the rotating fan blades. Vortex noise is a series of vortex flows formed by gas slipping or splitting when boundary layer separation occurs on the cross section of rotating blades, which radiates a kind of unsteady flow noise. The exhaust duct is directly connected with the outside, and the air velocity is very high. The air flow noise, fan noise and mechanical noise are radiated out through this channel. In order to control the noise of fan and exhaust duct, a silencing exhaust duct is designed. This silencing exhaust duct has a large length and is composed of air duct and exhaust noise reduction chamber. The working principle of the exhaust noise reduction chamber is similar to the resistive muffler. The sound attenuation effect can be improved by changing the sound-absorbing material (changing the sound-absorbing coefficient of the material), the thickness of the sound-absorbing material, the length and width of the exhaust passage and other parameters.
（4）消聲進氣道
(4) Anechoic inlet
機組工作在封閉的機房里面,從廣義上講,進氣系統(tǒng)包括機組的進風(fēng)通道和發(fā)動機的進氣系統(tǒng)。進風(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,氣流的噪聲和機組運轉(zhuǎn)的噪聲都經(jīng)進風(fēng)通道輻射到外面。發(fā)動機進氣系統(tǒng)的噪聲是由進氣門周期性開、閉而產(chǎn)生的壓力波動所形成,其噪聲頻率一般處于500 Hz以下的低頻范圍。在機房墻上設(shè)置了兩個消聲進氣道,分別作為機房的進風(fēng)口和發(fā)動機的進氣口。由于排風(fēng)造成的室內(nèi)負壓,使冷空氣自然通過消聲進氣道進入機房內(nèi),將機體散發(fā)的熱量順利排出。從而保證了機房內(nèi)有足夠的新鮮空氣。
The unit works in a closed machine room. In a broad sense, the air inlet system includes the air inlet channel of the unit and the air inlet system of the engine. The air inlet channel and the exhaust channel are directly connected with the outside world. The air flow rate is very high. The air flow noise and the unit operation noise are radiated to the outside through the air inlet channel. The noise of the engine intake system is caused by the pressure fluctuation caused by the periodic opening and closing of the intake valve. The noise frequency is generally in the low frequency range below 500 Hz. Two silencing air inlets are set on the wall of the machine room as the air inlet of the machine room and the air inlet of the engine. Due to the negative pressure in the room caused by the exhaust, the cold air naturally enters the machine room through the silencing inlet, and the heat emitted by the machine body is discharged smoothly. This ensures that there is enough fresh air in the machine room.