沼气发电机噪声来源主要部分

　　Main sources of noise from biogas generators

　　从产生的原因和部位上来分，沼气发电机组的噪声可以包括以下几部分：1. 排烟噪声；2 .机械噪声；3. 燃烧噪声；4. 冷却风扇和排风噪声；5. 进风噪声；6. 发电机噪声。下边分别就这六部分作一说明。

　　From the causes and locations of generation, the noise of biogas generators can include the following parts: 1 Smoke exhaust noise; 2 . Mechanical noise; 3. Combustion noise; 4. Cooling fan and exhaust noise; 5. Inlet air noise; 6. Generator noise. Below are explanations for each of these six parts.

　　1、排烟噪声

　　1. Smoke exhaust noise

　　排烟噪声是一种高温、高速的脉动性气流噪声，是发动机噪声中能量大，成分多的部分，比进气噪声及机体辐射的机械噪声要高得多，是发动机总噪声中主要的组成部分。它的基频是发动机的发火频率。排烟噪声的主要成分有以下几种：周期性的排烟引起的低频脉动噪声、排烟管道内的气柱共振噪声、汽缸的亥姆霍兹共振噪声、高速气流通过气门间隙及曲折的管道时所产生的噪声、涡流噪声以及排烟系统在管内压力波激励下所产生的再生噪声等，随气流速度增加，噪声频率显著提高。

　　Smoke exhaust noise is a high-temperature, high-speed pulsating airflow noise, which is the high-energy and multi-component part of engine noise. It is much higher than intake noise and mechanical noise radiated by the engine body, and is the main component of the total engine noise. Its fundamental frequency is the firing frequency of the engine. The main components of smoke exhaust noise include low-frequency pulsating noise caused by periodic smoke exhaust, air column resonance noise in the smoke exhaust duct, Helmholtz resonance noise in the cylinder, noise generated by high-speed airflow passing through valve clearances and tortuous ducts, vortex noise, and regenerative noise generated by the smoke exhaust system under pressure wave excitation inside the duct. As the airflow velocity increases, the frequency of the noise significantly increases.

　　2、机械噪声

　　2. Mechanical noise

　　机械噪声主要是发动机各运动部件在运转过程中受气体压力和运动惯性力的周期变化所引起的震动或相互冲击而产生的，其中为严重的有以下几种：活塞曲柄连杆机构的噪声、配气机构的噪声、传动齿轮的噪声、不平衡惯性力引起的机械震动及噪声。柴油机强烈的机械震动可通过地基远距离传播到室外各处，然后再通过地面的辐射形成噪声。这种结构噪声传播远、衰减小，一旦形成很难隔绝。

　　Mechanical noise is mainly generated by the vibration or mutual impact caused by the periodic changes in gas pressure and motion inertia force of various moving parts of the engine during operation. Among them, the most serious ones are the noise of the piston crank connecting rod mechanism, the noise of the valve train mechanism, the noise of the transmission gear, and the mechanical vibration and noise caused by unbalanced inertia force. The strong mechanical vibration of diesel engines can be transmitted to various places outdoors through the foundation, and then generate noise through the radiation on the ground. This type of structural noise has a long propagation distance and low attenuation, making it difficult to isolate once formed.

　　3、燃烧噪声

　　3. Combustion noise

　　燃烧噪声是柴油在燃烧过程中产生的结构震动和噪声。在汽缸内燃烧噪声声压级是很高的，但是，发动机结构中大多数零件的刚性较高，其自振频率多处于中高频区域，由于对声波传播频率响应不匹配，因而在低频段很高的汽缸压力级峰值不能顺利地传出，而中高频段的汽缸压力级则相对易于传出。

　　Combustion noise refers to the structural vibrations and noise generated during the combustion process of diesel fuel. The sound pressure level of combustion noise inside the cylinder is very high, but most of the components in the engine structure have high rigidity, and their natural frequencies are mostly in the mid to high frequency range. Due to the mismatch in response to the propagation frequency of sound waves, the peak pressure level of the cylinder in the low frequency range cannot be transmitted smoothly, while the cylinder pressure level in the mid to high frequency range is relatively easy to transmit.

　　水库业用沼气发电机噪声来源主要部分

　　Main sources of noise for biogas generators used in reservoir industry

　　4、冷却风扇和排风噪声

　　4. Cooling fan and exhaust noise

　　机组风扇噪声是由涡流噪声和旋转噪声组成的，旋转噪声由风扇的叶片切割空气产生周期性扰动而引起；涡流噪声是气流在旋转的叶片截面上分离时，由于气体的粘性引起的旋涡流，辐射一种非稳定的流动噪声。排风噪声、气流噪声、风扇噪声、机械噪声均是通过排风的通道辐射出去的。

　　The noise of the unit fan is composed of eddy current noise and rotational noise. The rotational noise is caused by the periodic disturbance generated by the cutting of air by the blades of the fan; Vortex noise is a non stable flow noise radiated by the vortex flow caused by the viscosity of the gas when the airflow separates on the rotating blade section. Exhaust noise, airflow noise, fan noise, and mechanical noise are all radiated through the exhaust duct.

　　5、进风噪声

　　5. Inlet air noise

　　沼气发电机组在正常工作的时候需要有足够的新风供应，一方面保证发动机的正常工作，另一方面要给机组创造良好的散热条件，否则机组无法保证其使用性能。机组的进风系统基本包括进风通道和发动机本身的进气系统，机组的进风通道必须能够使新风能够顺畅的进入机房，同时机组的机械噪声、气流噪声也可以通过这个进风通道辐射到机房外面。与自然进风的机组相比，采用涡轮增压方式进气的机组因为涡轮增压器的转速高，使得进气噪声要明显高于自然进风的机组。

　　The biogas generator set needs sufficient fresh air supply during normal operation to ensure the normal operation of the engine and create good heat dissipation conditions for the unit. Otherwise, the performance of the unit cannot be guaranteed. The air intake system of the unit basically includes the air intake channel and the engine's own air intake system. The air intake channel of the unit must be able to allow fresh air to enter the machine room smoothly, and the mechanical noise and airflow noise of the unit can also be radiated outside the machine room through this air intake channel. Compared with units with natural air intake, units with turbocharging intake have significantly higher intake noise due to the high speed of the turbocharger.

　　6、发电机噪声

　　6. Generator noise

　　发电机噪声包括定子和转子之间的磁场脉动引起的电磁噪声，以及滚动轴承旋转所产生的机械噪声。 根据上面对沼气发电机组的噪声分析，一般对于发电机组的噪声采用两种处理方式：机房做降噪或者采用*机组（防音型机组）。机房降噪需要对以上的噪声产生原因分别做处理，主要有以下方法：机房的进风口和排风口分别做隔音墙，同时风口要错开，进风通道和排风通道内设置进、排风消声器，同时设置进、排风消声百叶窗，这样消声量可以达到40分贝；机房内顶部和四周墙上铺设吸声系数高的吸、隔声板，主要用来消除室内混响，降低机房内声能密度，降低声源向外辐射的强度；为防止噪声通过大门向外辐射，可以设两极房门，并采用隔声性能好的双层隔声门；排烟管处可以选择标准9分贝的消声器或者40分贝的消声器，可以保证机组排烟噪声的有效控制。以上的处理同样可以抑制发电机的噪声，通过降噪处理，机房的噪声可以达到用户的要求。

　　Generator noise includes electromagnetic noise caused by magnetic field pulsation between the stator and rotor, as well as mechanical noise generated by the rotation of rolling bearings. According to the noise analysis of the biogas generator set above, there are generally two ways to deal with the noise of the generator set: noise reduction in the machine room or the use of * units (soundproof units). The noise reduction in the computer room requires separate treatment of the causes of the above noise, mainly through the following methods: soundproof walls should be installed at the inlet and outlet of the computer room, and the air outlets should be staggered. Inlet and exhaust mufflers should be installed in the inlet and exhaust channels, and inlet and exhaust soundproof louvers should be installed to achieve a noise reduction of 40 decibels; High sound absorption and insulation panels with high sound absorption coefficients are installed on the top and surrounding walls of the computer room, mainly used to eliminate indoor reverberation, reduce the sound energy density inside the computer room, and decrease the intensity of external radiation from the sound source; To prevent noise from radiating outward through the main entrance, two pole doors can be installed and double-layer soundproof doors with good sound insulation performance can be used; Standard 9-decibel or 40 decibel mufflers can be selected at the exhaust pipe to ensure effective control of the unit's exhaust noise. The above processing can also suppress the noise of the generator. Through noise reduction processing, the noise in the computer room can meet the requirements of users.

　　本文由  沼气发电机组   友情奉献.更多有关的知识请点击  /   真诚的态度.为您提供为全面的服务.更多有关的知识我们将会陆续向大家奉献.敬请期待.

　　This article is a friendly contribution from a biogas generator set For more related knowledge, please click / Sincere attitude To provide you with comprehensive services We will gradually contribute more relevant knowledge to everyone Coming soon.