Based on the working principle of gas generator set, it is difficult to use the method of reducing the noise source to eliminate noise, so the main thing is to effectively block its noise transmission path. The core of noise elimination technology is to use the law of natural attenuation of sound wave in propagation to reduce the pollution surface of noise. There are several ways to reduce noise: sound absorption, sound insulation and changing the direction of noise transmission. In practical engineering application, only one of them is often used. In this paper, a new combined noise reduction technology for gas generator set is proposed by using three methods.

(1)组合消声器

(1) Combined muffler

原来的消声器以阻性消声为主,功耗大,消声效果不理想。经仔细论证,应用三级组合降噪技术,将消声器改造为新型组合式消声器。该组合式消声器的主要组成部件有对喷消声减振腔、多孔式消声罩及吸声隔热层和吸声共振板等。声源通过对喷消声减振腔,可将中低频声源的噪声能量充分进行抗性耗散。

The original muffler is mainly resistive noise elimination, which consumes a lot of power, and the noise elimination effect is not ideal. After careful demonstration, the three-stage combined noise reduction technology is applied to transform the muffler into a new type of combined muffler. The main components of the combined muffler are the opposite jet anechoic cavity, the porous anechoic cover, the sound-absorbing insulation layer and the sound-absorbing resonance plate. The noise energy of the medium and low frequency sound source can be fully dissipated by the counter jet anechoic cavity.

(2)两级隔振衬垫

(2) Two stage isolation pad

控制机械噪声和燃烧噪声的有效办法是对机组进行隔振处理。燃气机、发电机与钢制底盘间装设复合隔振减振垫,底盘与基础之间亦垫上高能减振胶垫。经过两级隔振处理,不仅使机组的振动被有效隔断,而且使机组运行更加平稳,整体噪声显著降低。

The effective way to control the mechanical noise and combustion noise is to isolate the vibration of the unit. A composite vibration isolation pad is installed between the gas engine, generator and steel chassis, and a high-energy vibration damping rubber pad is 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)消声排风道

(3) Anechoic exhaust duct

风扇噪声是由旋转噪声和涡流噪声组成。旋转噪声由旋转风扇叶片切割空气流产生周期性扰动而引起。涡流噪声是在旋转叶片截面上发生边界层分离时,气体滑脱或分裂而成的一系列的漩涡流,从而辐射出一种非稳定的流动噪声。排风道直接与外界相通,空气流速很大,气流噪声、风扇噪声和机械噪声经此通道辐射出去。

Fan noise is composed of rotating noise and eddy noise. The rotating noise is caused by the periodic disturbance of the cutting air flow of the rotating fan blade. Vortex noise is a series of vortex flow formed by gas slippage or splitting when boundary layer separation occurs on the rotating blade section, which radiates an unsteady flow noise. The exhaust duct is directly connected with the outside world, the air velocity is very large, and the airflow noise, fan noise and mechanical noise radiate out through this channel.

(4)消声进气道

(4) Anechoic inlet

机组工作在封闭的机房里面,从广义上讲,进气系统包括机组的进风通道和发动机的进气系统。进风通道和排风通道一样直接与外界相通,空气的流速很大,气流的噪声和机组运转的噪声都经进风通道辐射到外面。发动机进气系统的噪声是由进气门周期性开、闭而产生的压力波动所形成,其噪声频率一般处于500Hz以下的低频范围。

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 large, and the noise of air flow and unit operation radiates 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, and its noise frequency is generally in the low frequency range below 500Hz.