Diesel generator set noise solution

A diesel generator set is an electromechanical integrated equipment that converts the chemical energy of fuel into electrical energy. With the booming development of computer networks and communication industries, the demand for reliable power supply from equipment is also increasing. Due to the problem of power supply duration in UPS power supply, diesel generator sets have broad development space. However, while diesel generators provide convenience for people, their inherent noise (diesel generator set noise) and emissions also affect our living environment, especially the noise of generator sets directly affecting people's work and life. As people's environmental requirements gradually increase, how to solve and overcome the above problems has become the key to the application and development of diesel generator sets. Here, we will focus on introducing the occurrence and solutions of noise in diesel generator sets.

1. Smoke exhaust noise of generator set

Smoke exhaust noise is a type of high-temperature and high-speed pulsating airflow noise, which is the most energetic and composed part of engine noise. It is much higher than intake noise and mechanical noise radiated by the engine body, and is the most important component of the total engine noise. Its fundamental frequency is the engine's firing frequency. The main components of smoke exhaust noise include low-frequency pulsation noise caused by periodic smoke exhaust, gas column resonance noise in smoke exhaust pipes, Helmholtz resonance noise in cylinders, noise generated by high-speed airflow passing through valve gaps and tortuous pipes, eddy current noise, and regeneration noise generated by smoke exhaust systems under pressure wave excitation in pipes. As the airflow speed increases, the frequency of noise significantly increases.

2. Mechanical noise of diesel generators

Mechanical noise mainly refers to 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 following: noise from piston crank connecting rod mechanism, noise from valve distribution mechanism, noise from transmission gears, mechanical vibration and noise caused by unbalanced inertia force. The strong mechanical vibration of a diesel engine can propagate to various outdoor locations through the foundation, and then form noise through the radiation from the ground. This type of structural noise propagates far and has low attenuation, making it difficult to isolate once it forms.

3. Combustion noise

Combustion noise is the structural vibration and noise generated by diesel during the combustion process. The sound pressure level of combustion noise inside the cylinder is very high, but most parts 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 frequency of sound wave propagation, the peak value of cylinder pressure level in the low frequency range cannot be smoothly transmitted, while the cylinder pressure level in the mid to high frequency range is relatively easy to transmit.

4. Cooling fan and exhaust noise

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