Causes And Control Methods Of Exhaust Noise Of Diesel Generator Set

Jiangsu Starlight Power Guide: When the diesel generator set is running, it usually produces 95-110dB (A) of noise. The noise from the unit operation will cause serious damage to the construction of the peripheral ring, so the noise must be controlled.

1. Main causes of exhaust noise.

Exhaust noise is the main part of engine noise. Its noise is generally 10-150B (A) higher than that of the engine manufacturer. The part with the largest energy and most components in the exhaust noise. Its fundamental frequency is the ignition frequency of the engine, and it should show the extension of the fundamental frequency and its higher harmonic in the entire exhaust spectrum.

The exhaust noise mainly includes the following components:

(1) Periodic exhaust noise. The frequency of low-frequency pulsating noise caused by exhaust is generally 63~125Hz, and the noise value is up to 105~125dB (A).

(2) Resonant noise of the gas column in the exhaust pipe.

(3) Resonance noise of the cylinder.

(4) The jet noise generated when the high-speed airflow passes through the exhaust valve annulus and zigzag pipes.

(5) The vortex noise and the regeneration noise generated by the exhaust system under the excitation of the pressure wave in the pipe form a continuous high-frequency noise spectrum with the frequency above 1000Hz. The frequency increases significantly with the increase of the air flow speed.

2. Control method of exhaust noise.

Muffler is the basic method to control exhaust noise. Proper selection of muffler (or muffler combination) can reduce exhaust noise by more than 30~40dB (A). According to the principle of noise elimination, muffler structures can be divided into resistive muffler and reactive muffler:

(1) Resistive muffler, also known as industrial muffler, is made of porous sound absorbing materials and arranged in the pipeline in a certain way. When the air flow passes through the resistive muffler, the sound wave will cause the vibration of air and fine fibers in the pores of the sound absorbing material. As a result of friction and viscous resistance, sound energy becomes heat energy and is absorbed, thus playing the role of noise elimination.

(2) Reactive muffler, called residential muffler, is a proper combination of pipes with different shapes and resonant cavities. With the help of reflection and interference caused by acoustic impedance mismatch caused by changes in pipe section and shape, it achieves the purpose of abdominal noise. The noise elimination effect is related to the shape, size and structure of the pipe. Generally, it has strong selectivity and is applicable to narrowband noise and low and intermediate frequency noise reduction.

The combination of a corrugated damping joint, an industrial muffler and a residential muffler is usually used to effectively isolate the transmission of air vibration and exhaust noise.

Starlight Power has advanced testing equipment, modern production technology, professional manufacturing technology, perfect quality management system, and strong technical research and development capabilities. It can provide 3KW～2500KW various specifications of ordinary, automatic, four protection, automatic switching, low noise and mobile generator sets, high quality and low energy consumption to meet the diverse power needs of customers, and can also meet users with different voltages and different frequencies. It is required to create a parallel power supply system for multiple units. If you are interested in our product or any question on generator, welcome to send email to sales@dieselgeneratortech.com.