scholarly journals Experience and perspectives of using active noise and vibration control for reduction of low frequency noise and vibration in gas guide systems of power plants

2020 ◽  
Vol 32 ◽  
pp. 123-128
Author(s):  
Andrey V. Vasilyev
Keyword(s):  
Vibration Control ◽  
Power Plants ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise And Vibration ◽  
Active Noise

APPROACHES TO CLASSIFICATION OF REDUCTION METHODS OF LOW FREQUENCY NOISE AND VIBRATION OF POWER PLANTS

Akustika ◽  
2021 ◽  
pp. 52-60
Author(s):  
Andrey Vasilyev
Keyword(s):  
Power Plants ◽  
Internal Combustion Engines ◽  
Vibration Reduction ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise And Vibration ◽  
Reduction Methods ◽  
Noise And Vibration Reduction

The importance of the problem of low-frequency noise and vibration reduction now may be considered as urgent. Increased influence of low-frequency noise and vibration may cause both human health problems and equipment damage. Power plants (internal combustion engines, compressors, heat-exchanges etc.) are one of the main low-frequency noise and vibration sources. The principles of classification of methods of power plants low-frequency noise and vibration reduction are suggested. Author is proposing energetic approach, according of which all the methods and arrangements of reduction may be classified as passive (adaptive and non-adaptive), active and hybrid passive-active. The classification is illustrated by the different examples, including constructions of mufflers and dampers, some of which are developed by author.

Experiences with Flow-Induced Vibration and Low Frequency Noise Due to Rotating Stall of Centrifugal Fan

1987 ◽  
Vol 6 (2) ◽  
pp. 76-87 ◽  
Author(s):  
Ken Okada
Keyword(s):  
Power Plants ◽  
Low Frequency ◽  
Rotating Stall ◽  
Frequency Noise ◽  
Centrifugal Fan ◽  
Low Frequency Noise ◽  
Flow Induced Vibration ◽  
Rotating Speed ◽  
Duct Systems ◽  
Centrifugal Fans

In recently constructed electric power plants, the forced draft fan (FDF), induced draft fan (IDF) and boost up fan (BUF) centrifugal fans and duct-systems have become larger in capacity and limited in space every year. As a centrifugal fan is enlarged, the diameter of the impeller is enlarged and its rotating speed is lowered. Therefore, there is an increasing tendency to generate a low frequency noise.5 In the case of an IDF or BUF, the rotating stall of the centrifugal fan frequently causes low frequency noise, since the inlet flow is often throttled during operation. If the hydrodynamic and acoustical characteristics are insufficient, a strong flow-induced vibration with low frequency noise is generated in the fan-duct system, and not only are problems caused in terms of structural strength, but also physical and physiological problems are induced due to low frequency noise.

EFFECTS OF AN ADAPTIVE-FEEDBACK ACTIVE NOISE CANCELLATION HEADSET ON WIDEBAND NOISE AND SPEECH INTELLIGIBILITY IN MANDARIN

2008 ◽  
Vol 20 (02) ◽  
pp. 123-131
Author(s):  
Jiun-Hung Lin ◽  
Shih-Tsang Tang ◽  
Wei-Ru Han ◽  
Chih-Yuan Chuang ◽  
Ping-Ting Liu ◽  
...  
Keyword(s):  
Speech Intelligibility ◽  
Low Frequency ◽  
Processing System ◽  
Noise Cancellation ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Signal Processing System ◽  
Adaptive Feedback ◽  
Active Noise Cancellation ◽  
Active Noise

Many industrial workers must wear hearing protectors in order to avoid hearing loss. Conventional passive methods, such as earmuffs, are ineffective against low-frequency noise, and so the present study developed a headset equipped with a digital signal processing system that implements adaptive-feedback active noise cancellation (FbAANC) to reduce the low-frequency noise. The proposed FbAANC headset system reduced the noise level by 40–60 dB at frequencies down to 63 Hz. We also evaluated the effects of the FbAANC headset on speech intelligibility on a disyllabic Mandarin word discrimination test (WDT) platform. For an SNR below–10 dB, the mean WDT score was 13%–32% higher with the FbAANC headset than without the headset in 30 subjects with normal hearing thresholds. These results suggest that the FbAANC headset would be useful for hearing protection in workplaces with high levels of wideband industrial noise.

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