The noise control of diesel generators rented out by Dongguan Generator
Due to the characteristics of their own industries, telecommunications companies in modern cities must operate flawlessly. In order to ensure the uninterrupted operation of communication equipment such as switches, diesel generators are generally used as backup power for generator rental. Once the mains power fails, the diesel generators are immediately started and the mains / oil engine conversion screen (ATS) ) Switching is provided by diesel generators to power communication equipment to ensure the normal operation of telecommunications services.
Because most of the telephone exchanges are located in densely populated areas, these areas have high environmental requirements, and diesel generator set noise often becomes the main source of pollution of the surrounding environmental noise. At present, society is increasingly demanding environmental protection. How to effectively control its noise pollution is a difficult task with great promotion value. This is also a major task of our communication construction and deserves more attention. . In order to do this work, we must first understand and analyze the noise composition of diesel generators.
Diesel noise is a complex sound source composed of multiple sound sources. According to the noise radiation method, diesel noise can be divided into aerodynamic noise and surface radiation noise. According to the generated mechanism, the radiated noise on the surface of a diesel engine can be divided into combustion noise and mechanical noise. Among them, aerodynamic noise is the main noise source.
Aerodynamic noise is caused by the unstable process of gas, that is, the disturbance of gas and the interaction between gas and objects. The aerodynamic noise directly radiated to the atmosphere includes: intake noise, exhaust noise, and cooling fan noise.
Intake noise is one of the main aerodynamic noises of diesel engines. It is caused by the pressure fluctuations caused by the periodic opening and closing of the intake valve. When the intake valve is opened, a pressure pulse is generated in the intake pipe, and as the piston continues to move, it is damped; when the intake valve is closed, a pressure pulse of a certain duration is also generated. This produces periodic intake noise. Its noise frequency component is mainly concentrated in the low frequency range below 200Hz. At the same time, when the airflow flows through the inlet valve cross section at high speed, turbulent flow separation occurs, resulting in the generation of high-frequency noise. Because the cross section of the inlet valve flow is constantly changing, turbulent noise has a certain frequency range. Mainly concentrated in the high frequency range above 1000Hz. When the natural frequency of the air column of the intake pipe is consistent with the main frequency of the periodic intake noise, the resonance noise of the air column will also be prominent in the intake noise.
For turbocharged engines, the turbocharger's speed is generally higher, so its intake noise is significantly higher than that of non-turbocharged engines. The noise of the turbocharger is caused by the rotation noise generated by the blades periodically cutting the air and the turbulence noise caused by the high-speed airflow. It is a continuous high-frequency noise, mainly distributed in the frequency range of 500 ~ 10000Hz. At present, most of our companies use turbocharged engines. -Generator repair
Intake noise is related to design factors such as the engine's intake method, intake valve structure, cylinder bore, and cam profile. For the same engine, the speed is the most affected. Double the speed can increase the intake noise by 10 ~ 15dB (A). http://ftfan.cn/