Causes of noise generated by diesel generator sets

The existence of diesel generators is convenient for our lives, providing us with backup power in case of accidents, but the diesel generator sets provide us with convenience, but also bring us noise, which directly affects our health. work and life.

Diesel engine block noise is a complex sound source made up of multiple sound sources. The main noise sources are diesel engines, including exhaust noise, mechanical noise and combustion noise, cooling fans and exhaust noise, air intake noise, generator noise, and noise generated by the transmission of ground vibration.

1. Exhaust noise. Exhaust noise is a kind of high-temperature, high-speed pulsating airflow noise, which is a kind of energy in engine noise, and its noise can reach more than 10, which is an integral part of the total noise of the engine.

2. Mechanical noise and combustion noise. Mechanical noise and combustion noise are difficult to distinguish strictly. Generally, noise caused by pressure fluctuations in the combustion of the cylinder through the cylinder head, piston, Lianxuan, crankshaft, and the body is called combustion noise. The noise generated by the impact of the piston on the cylinder liner and the mechanical impact of the moving parts is called mechanical noise. Generally, the direct injection diesel engine has higher combustion noise than the mechanical noise, while the non-direct injection diesel engine has higher mechanical noise than the combustion noise. However, the combustion noise is higher than the mechanical noise at low speed operation.

3. Cooling fan and exhaust noise. Unit fan noise is composed of eddy current noise, rotational noise, and mechanical noise. Exhaust noise, airflow noise, fan noise, and mechanical noise will propagate through the exhaust ducts, causing noise pollution to the environment.

4, the wind noise. The function of the air inlet passage is to ensure the normal operation of the engine and to create good heat dissipation conditions for the unit itself. The air inlet passage of the unit must be able to smoothly enter the engine room, but at the same time the mechanical noise and airflow noise of the unit will be radiated to the outside through this air inlet channel.

5. Transmission noise of ground vibration. The strong mechanical vibration of the diesel engine can be transmitted to the outside through the ground and then radiated through the ground.

In the case that the noise source cannot be reduced , comprehensive control of sound insulation, sound absorption and noise reduction can be adopted for the diesel generator set as needed.

1. Ventilation and noise reduction in the computer room. In actual work, we must consider both the effective noise reduction and the air flow required for the operation of the generator set.

(1) Machine room air intake and noise reduction system. In order to meet the cooling air and combustion air quantity required for the operation of the unit, the machine room is ventilated by mechanical air intake. In the machine room, two inlet air ducts are used for brickwork, and a low-noise axial flow fan is installed under the air inlet wall to supply air into the machine room. A large air volume combined muffler is installed in the air duct to absorb airflow noise and mechanical noise. An air inlet is opened on the outer wall of the air inlet, and a special aluminum alloy shutter and a protective screen are installed at the air inlet to prevent foreign matter from entering the air duct.

(2) Room exhaust ventilation system. There are two exhaust ducts in the brick room outside the machine room. Install a large air volume combined muffler in each exhaust duct to absorb exhaust noise and mechanical noise. The exhaust vent is arranged directly in front of the unit, and the front end of the unit radiator is provided with a vibration-damping flexible joint and a wind-conducting expansion sound-absorbing air duct, which is connected to the exhaust heat-removing channel. Special aluminum alloy shutters and protective screens are installed at the exit of the exhaust duct to prevent foreign matter from entering the air duct.

(3) Unit exhaust muffler

The exhaust muffler of the generator set randomly arranged has a small amount of muffling sound , and an efficient micro-perforated plate exhaust muffler designed for high, medium and low frequency noise is re-installed on the exhaust pipe of the unit. Its characteristics are large noise reduction, low resistance, high temperature resistance of materials and structures. The exhaust pipe is connected to the flue gas outlet of the unit by a metal bellows to reduce vibration and noise caused by the steel connection.

2. Sound absorption in the machine room.

Due to the brick-concrete structure , the generator house has strong acoustic reflection. In order to achieve the sound absorption effect, the wall and the top surface of the machine room are reasonably arranged with high-efficiency sound absorbing materials, and the sound absorbing layer structure is an aluminum alloy perforated gusset plate + centrifugal sound absorbing cotton + light steel keel + support hanger. The loudness in the equipment room is also greatly reduced, which greatly improves the working conditions and improves the sound insulation performance of the equipment room.

3. Sound insulation system.

In order to ensure good sound insulation performance of the equipment room, a fireproof soundproof door is installed at the communication room outside the machine room, and the door sealing material is a rubber sealing strip. Other holes that cause sound leakage are blocked with brick walls.