Where does the noise of diesel generator set come from?

Where does the noise of diesel generator set come from?
The main noise sources are diesel engine generation, including: exhaust noise, mechanical noise and combustion noise, cooling fan and exhaust noise, air intake noise, generator noise, noise generated by the transmission of foundation vibration, etc.:
exhaust noise
Exhaust noise is a high-temperature, high-speed pulsating airflow noise, which has the largest energy in engine noise. Its noise can reach more than 100db, and it is the most important part of the total engine noise. The exhaust noise generated during the operation of the generator is directly discharged through the simple exhaust pipe (the original exhaust pipe of the generator set), and with the increase of the airflow speed, the noise frequency also increases significantly, which affects the life and work of the nearby residents.
Mechanical noise and combustion noise
Mechanical noise is mainly caused by the sensation or mutual impact caused by the periodic changes of gas pressure and motion inertial force during the operation of various moving parts of the engine. It has the characteristics of far noise transmission and low attenuation. Combustion noise is the structural noise and noise produced by diesel fuel during combustion.
Cooling fan and exhaust noise
The fan noise of the unit is composed of eddy current noise, rotation noise and mechanical noise. Exhaust noise, airflow noise, fan noise, and mechanical noise will be transmitted through the exhaust channel, thereby causing noise pollution to the environment.
air intake noise
The function of the air inlet channel is to ensure the normal operation of the engine and to create good heat dissipation conditions for the unit itself. It is necessary for the air inlet channel of the unit to allow the air intake to enter the machine room smoothly, but at the same time, the mechanical noise and airflow noise of the unit will also be radiated to the outside of the machine room through this air inlet channel.
ground vibration transmitted noise
The strong mechanical vibration of the diesel engine can be transmitted to various places outdoors through the foundation, and then radiate noise through the ground. The principle of noise reduction in the diesel generator room is to select high-efficiency sound-absorbing materials and noise-reducing and muffling equipment to perform noise-reduction processing on the intake, exhaust passages and exhaust systems on the premise of ensuring the ventilation conditions of the diesel generator set, that is, without reducing the output power. , so that the noise emission reaches the national standard (85dB(A)).