scholarly journals Experimental Study of Pipes Shape Effect on Noise Reduction

2017 ◽  
Vol 5 (1) ◽  
pp. 71-86
Author(s):  
Muna S. Kassim ◽  
Ammar Fadhil Hussein Al-Maliki
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Noise Reduction ◽  
Power Plants ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Shape Effect ◽  
Pipe Length ◽  
Exhaust Noise

Internal combustion engine is a major source of noise pollution. These engines are used for various purposes such as, in power plants, automobiles, locomotives, and in various manufacturing machineries. The noise is caused by two reasons; the first reason is the pulses which created when the burst of high pressure gas suddenly enters the exhaust system, while the second reason is the friction of various parts of the engine where the exhaust noise is the most dominant. The limitation of the noise caused by the exhaust system is accomplished by the use of silencers and mufflers. The aim of this study is the reduction of the noise by changing its inlet and outlet pipe length and shape. Also the losses in noise for different length and shapes have been investigated experimentally. The results show that the corrugated pipe is preferable for noise reduction.

Attenuation analysis and acoustic pressure levels for double expansion chamber reactive muffler: Part 2

2018 ◽  
Vol 49 (6) ◽  
pp. 241-245
Author(s):  
Mahesh V Kulkarni ◽  
Ravindra B Ingle
Keyword(s):  
Acoustic Pressure ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Exhaust Pipe ◽  
Expansion Chamber ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Maximum Contribution ◽  
Exhaust Noise

The major source responsible for noise pollution is internal combustion engine. These engines are used for various purposes such as in automobiles, locomotives, and in various manufacturing machineries. In an engine, the exhaust noise and the noise produced due to friction of various parts of the engine share maximum contribution to noise pollution. Muffler is a device used to reduce noise within the exhaust system. It is arranged along the exhaust pipe for the purpose of noise attenuation. The paper describes the propagation of pressure wave in a double expansion chamber reactive muffler. The approach is useful in analysis of damping for propagation of harmonic pressure waves. The purpose of paper is to describe the finite element analysis of double expansion chamber reactive muffler using pressure acoustics and to validate it with experimental evaluation using two-load method.

Analysis for effect of pores on acoustic performance of reactive muffler

2021 ◽  
pp. 095745652110307
Author(s):  
Pravin P Hujare ◽  
Vishal R Mote ◽  
Ashok R Mache ◽  
Deepak P Hujare ◽  
Sandeep S Kore
Keyword(s):  
Numerical Analysis ◽  
Transmission Loss ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Engine Exhaust ◽  
Target Frequency ◽  
Acoustic Performance ◽  
Outlet Pipe ◽  
Exhaust Noise

The major source of noise pollution was an internal combustion engine. Henceforth, the design of the engine exhaust system was a tough challenge for automotive industries. The mufflers have been used to moderate the exhaust noise from the engine to the neighboring atmosphere. So in domestic as well as the industrial application, it is required to reduce noise levels to prevent human hazards. The performance of muffler is measured in terms of transmission loss. The transmission loss of reactive muffler is depending on its geometry. This article describes the effects of pores at the inlet pipe and outlet pipe of the reactive muffler on its performance capacity at a target frequency. It is found that the muffler performance is dependent on the number and position of pores. The single chamber and double chamber reactive mufflers are used for the study. The numerical analysis is performed by COMSOL Multiphysics software. The numerical analysis result of the different models of the muffler is compared with experimental analysis. The purpose of the study is to investigate the effect of pores in inlet and outlet pipe to maximize the TL at the target frequency of reactive muffler.

scholarly journals Experimental Study of Orifice Shape Effect on Noise Reduction of Silencer

2020 ◽  
Vol 7 (2) ◽  
pp. 1-12
Author(s):  
Muna S. Kassim ◽  
Ammar Fadhil Hussein Al-Maliki ◽  
Hayder M. Mohammed
Keyword(s):  
Experimental Study ◽  
Noise Reduction ◽  
Transmission Coefficient ◽  
Internal Combustion Engines ◽  
Noise Pollution ◽  
Shape Effect ◽  
Combustion Engines ◽  
Transmission Losses ◽  
Matlab Program ◽  
Different Shapes

Abstract: Noise pollution is one of the most problems caused by internal combustion engines. In this study, the reduction of noise by changing the orifice shapes and inserting tape is experimentally investigation. The effect of orifice shape on noise reduction of silencer is presented. The calculation of transmission losses and transmission coefficient of noise for different shapes of orifice by using MATLAB program is obtained. In addition, the frequency for maximum and minimum losses is obtained. The results showed that the use of the square orifice and helical tape were better options to reduce the noise in the silencer.

Calculation of Acoustic Efficiency of Exhaust Silencers for Automotive Internal Combustion Engines

2021 ◽  
pp. 41-47
Author(s):  
Vladimir Tupov ◽  
O. Matasova
Keyword(s):  
Acoustic Waves ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Control Point ◽  
Plane Waves ◽  
Exhaust System ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Exhaust Noise ◽  
Insertion Losses

Insertion losses as the main characteristic that mathematically describes the acoustic efficiency of a noise silencer has been considered. This characteristic shows the reduction of noise generated by its source, in particular by the internal combustion engine’s exhaust system, at the control point as a silencer use result. Has been presented a mathematical description of the insertion losses, and have been considered parameters necessary for calculating this characteristic. Has been demonstrated the analytical dependence of impedance for the sound emission by the exhaust system’s end hole from the coefficient of acoustic waves reflection by this hole. The performed analysis of the widely used formulas for calculating the coefficient of sound reflection by the end hole has showed their insufficient accuracy for project designs performing. Have been proposed calculation dependences providing high accuracy for calculations of the reflection coefficient modulus, and the attached length of the channel end hole without a flange in the entire range of the existence of plane waves in it. It has been shown that the end correction of this hole at ka = 0 is 0.6127, and not 0.6133, as it was mistakenly believed until now in world acoustics. Has been proposed a method for calculation the exhaust noise source internal impedance. This method more accurately, in comparison with the already known ones, describes the acoustic processes in the internal combustion engine’s exhaust manifold, thanks to increases the accuracy of calculation the silencer acoustic efficiency, that allows develop the silencer at the early stages of the design of an automotive internal combustion engine.

SOFTWARE DEVELOPMENT FOR ESTIMATION OF LOW FREQUENCY SOUND PROPAGATION IN GAS GUIDES OF POWER PLANTS TAKING TO ACCOUNT ACTIVE SOUND SOURCES

2020 ◽  
Vol 5 (4) ◽  
pp. 36-44
Author(s):  
A V Vasilyev
Keyword(s):  
Sound Source ◽  
Power Plants ◽  
Sound Propagation ◽  
Combustion Engine ◽  
Source Parameters ◽  
Low Frequency ◽  
Sound Sources ◽  
Software Application ◽  
Frequency Sound ◽  
Exhaust Noise

This paper is devoted to the problems of modelling and calculation of propagation of low frequency sound in gas guides of power plants taking to account active sound sources. The structure of software for prediction and calculation of low-frequency sound propagation in gas guides have described. Software uses four-pole method and takes to account radiation from additional (active) sound course. By using software it is possible to estimate sound source parameters to provide efficient sound attenuation. Examples of software application to calculation of intake and exhaust noise of internal combustion engine are described. The results of calculations show the possibilities of four-pole method software using to design acoustically the parameters of gas guides and mufflers for the different fields of applications.

scholarly journals Calculation of the required noise reduction of a engine exhaust system

2020 ◽  
Vol 320 ◽  
pp. 00017
Author(s):  
Olga Matasova ◽  
Vladimir Tupov
Keyword(s):  
Noise Reduction ◽  
Combustion Engine ◽  
Early Stage ◽  
Power Level ◽  
Exhaust System ◽  
Vehicle Design ◽  
Engine Exhaust ◽  
Sound Power Level ◽  
Initial Stage ◽  
Theoretical Assessment

The problem of reduction of internal combustion engine (ICE) noise is most urgent at present when the fleet of vehicles has significantly expanded and their power has increased. Reactive mufflers are often used to solve it. The initial stage in the design of mufflers is a theoretical assessment of the frequency spectrum of sound power level (SPL) of an unmuffled ICE noise source, comparing it with the calculated maximum permissible spectrum and determining the required amount of its reduction in standard frequency bands. The paper presents a method for calculating the required noise reduction of a transport engine exhaust using the example of a two-stroke ICE of the class of 125 cm3. Thus, the designer has the opportunity to develop mufflers, the acoustic efficiency of which meets the calculated required noise reduction values, already at an early stage of the vehicle design.

Validation of set up for experimental analysis of reactive muffler for the determination of transmission loss: Part 1

2018 ◽  
Vol 49 (6) ◽  
pp. 237-240
Author(s):  
Mahesh V Kulkarni ◽  
Ravindra B Ingle
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Experimental Analysis ◽  
Transmission Loss ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Exhaust Pipe ◽  
Set Up ◽  
Element Method

The internal combustion engine is the major source responsible for noise pollution. In an engine, the exhaust noise and the noise produced due to friction of various parts of the engine share maximum contribution to noise pollution. A muffler is a device used to reduce noise within the exhaust system. It is arranged along the exhaust pipe for the purpose of noise attenuation. In this article, the set up for experimental analysis is developed to predict the acoustic performance of reactive muffler using the two-load method, and it is validated by measuring transmission loss of known reactive muffler model by using finite element method. For the model, transmission loss obtained from experimental analysis was compared with that obtained from the finite element method. From the result, it can be concluded that the setup developed for experimental analysis is reliable to determine transmission loss of exhaust muffler, for low to mid frequency range.

Research on Tail Pipe for Engine Performance and Exhaust Noise

2014 ◽  
Vol 945-949 ◽  
pp. 770-776
Author(s):  
Shou Li Yuan ◽  
Chao Zhang
Keyword(s):  
Engine Performance ◽  
Exhaust System ◽  
Exhaust Pipe ◽  
Pipe Length ◽  
Tail Pipe ◽  
Engine Model ◽  
Calculation Results ◽  
Exhaust Noise ◽  
Pipe Geometry ◽  
System Coupling

The whole engine model，including intake system, coupling with exhaust system, is established by the software GT-POWER. Through the parameter change of tail pipe geometry, it is analyzed in this paper how the tail pipe geometry affect tail pipe noise. With the test data and the simulation calculation results, it analyses the influence of the tail exhaust pipe length, diameter, shape, terminal bending angle on engine performance and tail pipe noise, so as to choose suitable design parameter of tail pipe to meet the requirements of engine performance and the tail pipe noise.

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