Noise Character of Cooling Tower and Control Discussion

2012 ◽  
Vol 217-219 ◽  
pp. 2674-2677
Author(s):  
Huan Liu ◽  
Chang Zheng Chen ◽  
Hao Zhou
Keyword(s):  
Noise Reduction ◽  
Sound Absorption ◽  
Cooling Tower ◽  
Noise Control ◽  
Sound Insulation ◽  
Controlling Measures ◽  
And Control

This article takes the noise control of a cooling tower for a residence area as an example. On the base of measuring data, the noise resource is analyzed and the character of the noise resource is discussed. In the aspects of sound elimination, sound absorption and sound insulation, a set of practical controlling measures are elaborated. The result shows that the effect of noise reduction in this scheme is evident, and in the meantime the wind volume and temperature for the equipment are satisfying as well. Perfect effects of noise reduction can be obtained in the working project.

Study on Sound Insulation Performance of Pressure Relief Wall of Transformer Chamber

2021 ◽  
Vol 263 (1) ◽  
pp. 5197-5202
Author(s):  
Fabing Rong ◽  
Zhongjie Cheng ◽  
Peijie Liu
Keyword(s):  
Noise Reduction ◽  
Sound Absorption ◽  
Vibration Isolation ◽  
Noise Control ◽  
Sound Insulation ◽  
Noise Emission ◽  
Pressure Relief ◽  
Actual Case ◽  
Noise Interference ◽  
Insulation Performance

The problem of noise nuisance in indoor substation becomes more and more sensitive. The noise emission index of substation has become an important technical index of substation design. The noise control of indoor substation mainly adopts "auxiliary noise reduction technology" such as sound absorption, sound insulation and vibration isolation. The sound insulation performance of the pressure relief wall in the main transformer room of indoor substation is the key link of noise control. In order to reduce the noise interference, this paper selects the common sound insulation structure of the pressure relief wall, analyzes the main influencing factors of noise reduction, selects the sound insulation structure suitable for the pressure relief wall in the main transformer room of indoor substation, and tests the effectiveness of noise reduction of the sound insulation structure in the actual case. Based on the research results, the sound absorption structure in the main transformer room is arranged on the other indoor wall outside the pressure relief wall, and the pressure relief wall mainly considers the structure of sound insulation, which can effectively reduce the noise impact of the main transformer room.

scholarly journals Методы определения характеристик звукопоглощения строительных материалов и звукоизоляции конструкций (обзор)

2020 ◽  
Vol 45 (4) ◽  
Author(s):  
Keyword(s):  
Noise Reduction ◽  
Sound Absorption ◽  
Building Materials ◽  
Developed Countries ◽  
Reduction Factor ◽  
Sound Insulation ◽  
Reverberation Chamber ◽  
Normative Documents ◽  
Urban Conditions ◽  
First Time

Исследование акустических характеристик строительных материалов и конструкций необходимо для комфортной жизни людей в городских условиях. Несмотря на то что в нормативных документах развитых государств есть ряд методов их определения, единого понимания самих характеристик и путей их адекватного определения до сих пор нет. В настоящей работе мы попытались систематизировать и дать критический обзор нормативных документов, содержащих методы определения звукопоглощающих свойств материалов и звукоизоляционных характеристик конструкций. Впервые выявлены присущие разным методам закономерности определения характеристик звукопоглощения и звукоизоляции. Определены наиболее характерные показатели звукопоглощения. Произведено ранжирование по коэффициенту уменьшения шума NRC наиболее часто применяемых строительных материалов. Названы области применения рассматриваемых методик, проанализированы их преимущества и ограничения. Ключевые слова: коэффициент уменьшения шума, звукопоглотитель, импедансная труба, реверберационная камера The study of the acoustic characteristics of building materials and structures is necessary for provision of comfortable life of people in urban conditions. Despite the fact that in the normative documents of developed countries there are a number of methods for their determination, there is still no common understanding of the characteristics themselves and the ways of their adequate determination. In this work we tried to systematize and give a critical review of regulatory documents containing the methods for determining the sound-absorbing properties of materials and the sound-insulating characteristics of structures. For the first time the regularities in determination the characteristics of sound absorption and sound insulation inherent in different methods have been revealed. The most characteristic indicators of sound absorption have been determined. The ranking of the most commonly used building materials was made according to the noise reduction factor (NRC). The areas of application of the considered methods are presented, their advantages and limitations are analyzed. Keywords: noise reduction factor, sound absorber, impedance tube, reverberation chamber

Study on Automation Control with Noise Control of Oil Sucking Machine

2013 ◽  
Vol 738 ◽  
pp. 195-198 ◽  
Author(s):  
Huan Liu ◽  
Han Cui
Keyword(s):  
Finite Element ◽  
Noise Reduction ◽  
Practical Problem ◽  
Noise Control ◽  
Electric Machine ◽  
Sound Insulation ◽  
Technical Requirement ◽  
Finite Element Models ◽  
Local Domain ◽  
Automation Control

Sound insulation encasing is an effective device for noise reduction. The paper used the electric machine and reductor of oil sucking machine as an example, a controlling approach of installing sound insulation encasing has been found based on a analysis of noise characteristic, at the same time, the effectiveness of sound insulation encasing is analyzed, after establishing finite element models by using sysnoise software, and the deficiency of noise reducing effectiveness in local domain is shown. Effectiveness of noise reducing is better and meets the technical requirement, after amendment design, and this provides some reference to solve practical problem.

Development of Natural Fibre Non-Woven Materials’ Application as Car Interiors for Noise Reduction

2011 ◽  
Vol 332-334 ◽  
pp. 1531-1534 ◽  
Author(s):  
Ming Ma ◽  
Yuan Bai ◽  
Xiao Ming Qian
Keyword(s):  
Noise Reduction ◽  
Reference Point ◽  
Sound Absorption ◽  
Noise Control ◽  
Natural Fibre ◽  
Noise Sources ◽  
Absorption Properties ◽  
Vehicle Noise ◽  
Nonwoven Materials ◽  
Potential Market

This document mainly introduces the evaluation of vehicle noise, noise sources and noise control. The development of fibers used for noise reduction materials is described as well. Besides, it analyzes the advantages and the necessities of the natural fibre nonwoven materials applied for the noise control, illustrates the present research status and the factors that introduces the sound absorption properties of the natural fibre nonwoven composites used for noise reduction. The paper also gives some reference point for advice to the development of automotive nonwoven materials. it shows that natural fibre nonwoven materials have a huge potential market and worthy for scholars to make a further study.

Considerations for the Reduction of Noise in Ship Installations of Gas Turbines

1960 ◽  
Vol 82 (3) ◽  
pp. 205-214
Author(s):  
Edward M. Herrmann
Keyword(s):  
Noise Reduction ◽  
Gas Turbines ◽  
Sound Absorption ◽  
Sound Insulation ◽  
Specific Information ◽  
Airborne Sound

General noise reduction considerations for shipboard installation of gas turbines are discussed. Specific information relating to sound-absorption materials, duct treatments, structureborne sound isolation, and airborne sound insulation is graphically presented.

Research and Application of Building Enclosing Structure Used in Equipment Noise Control

2013 ◽  
Vol 423-426 ◽  
pp. 1272-1278
Author(s):  
Nan Xu
Keyword(s):  
Porous Material ◽  
Sound Absorption ◽  
Noise Control ◽  
Building Envelope ◽  
Sound Insulation ◽  
Hard Material ◽  
Noise Elimination ◽  
Control Engineering ◽  
Airborne Sound ◽  
Properties Of Materials

Porous material has a function of sound absorption, dense hard material can prevent the spread of airborne sound. The building envelope which is made up of different properties of materials, with good effects on sound insulation, sound absorption and noise elimination, can be widely used in noise control engineering.

scholarly journals Study on Noise Prediction Model and Control Schemes for Substation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chuanmin Chen ◽  
Yang Gao ◽  
Songtao Liu
Keyword(s):  
Noise Reduction ◽  
Power Transmission ◽  
Noise Control ◽  
Noise Pollution ◽  
Electrical Equipment ◽  
Excess Noise ◽  
Control Schemes ◽  
Negative Effect ◽  
Reduction Methods ◽  
And Control

With the government’s emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation’s acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation’s design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods.

Noise reduction performance of a low energy façade-integrated mechanical ventilator

2020 ◽  
pp. 1351010X2096618
Author(s):  
Marco A Oliveira ◽  
Luis Bragança ◽  
Sandra M Silva ◽  
Dinara Paixão ◽  
Julieta António
Keyword(s):  
Energy Consumption ◽  
Noise Reduction ◽  
Energy Demand ◽  
Noise Control ◽  
Control Strategies ◽  
Minimum Energy ◽  
Sound Insulation ◽  
Mechanical Ventilator ◽  
Noise Emission ◽  
Acoustic Comfort

Acoustic comfort and indoor air quality are essential for the health and wellbeing of the occupants of the building. Thus, the façade must guarantee enough sound insulation and ventilation conditions. However, these aspects conflict because opening windows or using ventilation openings reduces the sound insulation of the envelope and allows the exterior noise entrance. To limit noise transmission into the building, ventilators use passive, active or hybrid noise control techniques. This work addresses the noise reduction performance of a mechanical ventilator for façades, evaluating the effect of different options of passive noise control strategies in the sound insulation of the proposed ventilator. In addition, the air change rate and energy consumption of the ventilator were also investigated. Three prototypes were fabricated and tested at an acoustic chamber, along with ventilation tests carried out in a room equipped with a blower door. CFD simulations were used to enhance the aeraulic geometry of the prototypes, prior to its fabrication. The acoustic experiments showed Dn,e,w values up to 55 dB and noise emission levels lower than 25 dB(A). The use of resistive sound absorbers proved to be more effective in mitigating noise than reactive absorbers, over the entire frequency range. The ventilation tests revealed air change rates of 3.7 h−1 at 50 Pa, while the ventilator’s annual energy consumption was 17.52 kWh. The results highlight the proposed device as a viable alternative for decentralised mechanical ventilation, capable of ensuring noise protection and satisfactory ventilation rates, under a sustainable perspective of minimum energy demand.

Theoretical End Experimental Evaluation of Perforations Effect on Sound Insulation

2017 ◽  
Author(s):  
Olga Khrystoslavenko ◽  
Raimondas Grubliauskas
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Sound Absorption ◽  
Low Frequency ◽  
Experimental Methods ◽  
Glass Wool ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Sound Reduction

To design a sound-absorbing panel, it is important to identify factors that affect the maximum sound absorption of low, middle and high frequency sounds. Perforation effect is very important for the noise-reducing and noiseabsorbing panels. Perforations are often used for sound reduction. Experimental data shows that the perforation is very effective to absorb low-frequency noise. In the presented study, influence of perforation coefficient of noise reduction was analyzed with theoretical and experimental methods. The experiments were conducted in noise reduction chamber using an perforated construction with glass wool filler. Sound reductions index of 15 dB indicates good acoustic properties of the panel.

scholarly journals Sound-Absorption Coefficient of Bark-Based Insulation Panels

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1012 ◽  
Author(s):  
Eugenia Mariana Tudor ◽  
Anna Dettendorfer ◽  
Günther Kain ◽  
Marius Catalin Barbu ◽  
Roman Réh ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
Residential Buildings ◽  
Coarse Grained ◽  
Sound Absorption Coefficient ◽  
Sound Insulation ◽  
Formaldehyde Resin ◽  
Frequency Interval ◽  
Spruce Bark

The objective of this study was to investigate the sound absorption coefficient of bark-based insulation panels made of softwood barks Spruce (Picea abies (L.) H. Karst.) and Larch (Larix decidua Mill.) by means of impedance tube, with a frequency range between 125 and 4000 Hz. The highest efficiency of sound absorption was recorded for spruce bark-based insulation boards bonded with urea-formaldehyde resin, at a level of 1000 and 2000 Hz. The potential of noise reduction of larch bark-based panels glued with tannin-based adhesive covers the same frequency interval. The experimental results show that softwood bark, an underrated material, can substitute expensive materials that involve more grey energy in sound insulation applications. Compared with wood-based composites, the engineered spruce bark (with coarse-grained and fine-grained particles) can absorb the sound even better than MDF, particleboard or OSB. Therefore, the sound absorption coefficient values strengthen the application of insulation panels based on tree bark as structural elements for the noise reduction in residential buildings, and concurrently they open the new ways for a deeper research in this field.

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