NOISE REDUCTION OF TWO WHEELER BY REDESIGNING SPIRAL RESONATOR & PERFORATED TUBE

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 01, January 2019, pp , Article ID: IJMET_10_01_195 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed NOISE REDUCTION OF TWO WHEELER BY REDESIGNING SPIRAL RESONATOR & PERFORATED TUBE (Professor, Department of Mechanical Engineering, Pace IT&S, Ongole, A.P, India) ABSTRACT Background: In this study, the Component of normal exhaust system such as muffler or silencer shell, perforated tube, spiral resonator design have been carried out by SOLIDWORKS and a Finite Element Approach have presented for modeling and analysis of muffler noise developed at different locations as well as temperature distribution over silencer. The main objective of this study was to simulate and investigate the performance of a general muffler by simulation and experimental technique. Methods: In order to minimize two-wheeler noise, testing were carried out in a Bajaj pulsar two wheeler by redesigning a spiral resonator andperforator tube which is capable of attenuating noise level by about 7 dba (Decibels). Results: The results obtained from simulation that as the distance increases from inlet of silencer the sound pressure level decreases gradually. Conclusions: Obtained results shows a significance decrease of sound pressure level about 7 dba from existing silencer to new designed silencer Keywords: ANSYS-FLUENT, CFD & FEA, Mesh Controls,Noise Reduction, Perforated Tube, Spiral Resonator and SOLIDWORKS etc.. Cite this Article:, Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube, International Journal of Mechanical Engineering and Technology, 10(1), 2019, pp BACKGROUND I.C. Engines are equipped with an exhaust muffler or silencer, to suppress the acoustic pulse generated by the combustion process. A high intensity pressure wave generated by combustion inside the engine cylinder which propagates along the exhaust pipe and to attenuate this airborne noise of the engine sound reducer called muffler uses to decrease the velocity of the exhaust gases and either absorbs sound waves or cancel them by interference with reflected waves coming from the same source. Internal combustion engines are a major editor@iaeme.com

2 source of noise pollution after industries. Noise is an environmental pollutant with recognized impacts on the psychological and physiological health of humans. Noise pollution made by engines turns into a crucial concern when used in residential areas or areas where noise creates hazard. Countries like India two-wheelers are becoming increasingly prevalent as a means of transportation. If noise level of more than 80 dba (decibels) is harmful for human being. Mufflers have been developed over the last ninety years based on electro- acoustic analogies and experimental trial and error. G. W. Stewart (1922) used electro acoustic analogies in deriving the basic theory and design of acoustic filters. Later D. D. Diviset al.(1954) published results of a systematic study on mufflers. Igarashi et al. (1958) calculated the transmission characteristics of mufflers using equivalent electrical circuits. A.V Sreenath and L. Munjal (1970) gave expression for the attenuation of mufflers using the transfer matrix approach. The expression they developed was based on the velocity ration concept. Later,againL.Mujal(1975) modified this approach to include the convective effects due to flow. C. I.J. Younget al.(1975) used the finite element method to predict four-pole parameters and then the transmission loss of complex shaped mufflers for the case of no flow. A.K.M.Mohumuddin (2005) did experimental study of noise and back pressure for silencer design characteristics. The main objective of this study was to find the relationship between the back pressure and the noise level. He concludes that the relationship between the noise and the back pressure is inversely proportional. S.N.Y.Gerges et al. (2005) paper implies the basic formulation of the Transfer Matrix Method (TMM) to predict the Transmission Loss of muffler elements has been summarized. Experimental measurements were carried out for different muffler configurations and compared to the numerical results obtained from TMM. It was observed that in general a good agreement is obtained between the experimental and numerical results. Reza Kashani et al.(2011) approach were based on adding tuned acoustic damping to the combustion environment. By incorporating in-situ adjustability into acoustic damping devices, they can change their mechanical attributes, e.g., mass and/or stiffness, and adapt themselves in a semi-active manner to the varying instability frequency. Takashi Yasuda(2013) studied on an automobile muffler with the acoustic characteristic of low-pass filter and Helmholtz resonator. Based on the typical structure, a muffler with an interconnecting hole on the tail pipe was proposed to improve its acoustic performance. Acoustic performances of the proposed muffler were studied experimentally and theoretically in frequency and time domain. Results showed that the specimen muffler had attenuation performances of low-pass filter and Helmholtz resonator when an interconnecting hole was designed on the tail pipe.the paper of Vishal Vaidya et al. (2014), emphasizes the role of resonator on transmission loss in air intake system and its sound pressure level reduction. Jigar H. Chaudhari (2014) speaks on the various types of mufflers and design of exhaust system belonging engine has been studied. The object of this study is choosing muffler design which one reduces a large amount of noise level and back pressure of engine. In designing, there are various parameters which has to take in to the consideration. These parameters affect the muffler efficiency. Absorptive muffler design uses only absorption of the sound wave to reduce the noise level without disturbing the exhaust gas pressure. Ehsan Sabah M et al.(2013) were conducted an experimental test for noise attenuation in gasoline engine with different Types of mufflers. Compares between three different types of an exhaust muffler for noise attenuation of single cylinder four stroke air-cooled gasoline engine. A set of conclusions achieved about the effect of the mufflers chamber's expansion ratio, chambers length, and wall thickness. Sound attenuation of 12.5, 15 and 16 dba is achieved with, multichamber reactive Muffler, concentric-tube resonator muffler and combined reactive and dissipative muffler. Wei-Hong Tan et al.(2013) conducted an expansion chamber muffler with the use of a micro-perforated panel (MPP) to improved acoustic performance. The result showed that the performance of this muffler with an 80mm air cavity depth improved by editor@iaeme.com

3 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube 75%.At the same time they found that, the noise level was reduced by 20 dba for the frequency band of 125Hz to 4000Hz of the engine running at 3000±200 rpm. Bin Li1et al.(2013) experimented a novel and practical acoustic energy harvesting mechanism to harvest traveling sound at low audible frequency is introduced and studied both experimentally and numerically. The acoustic energy harvester in this study contains a quarter-wavelength straight tube resonator with Lead Zirconate Titanate (PZT) piezoelectric cantilever plates placed inside the tube. M. L. Munjal (2013) development of long strand fibrous materials that can be used in hot exhaust systems without binders has led to the use of combination mufflers in exhaust systems. Breakthroughs have been achieved in the prediction and control of breakout noise from the elliptical and circular muffler shell as well as the end plates of typical mufflers.yu, X et al.(2015) A muffler in the exhaust system of an internal combustion engine reduces its power and increases fuel consumption. Jesus Madrigal et al.(2017)uses transfer matrix method to calculate the frequency dependence of the transmission of longitudinal elastic waves for a layered structure where the specific acoustic impedance of the layers with odd numbering follows a Gaussian distribution, while the inserted even layers have the same impedance as the propagation medium 2. DIMENSIONS AND DESIGN OF MODELS BY SOLIDWORKS The SOLIDWORKS CAD Software is a Mechanical Design Automation application that lets designers quickly sketch out ideas, experiment with features and dimensions, and produce models and detailed drawings Design of spiral Resonator Diameter of a spiral resonator, d = 70 mm, Diameter of mandrel, d m = 25 mm Thickness of spiral profile, g = 3 mm, Lead of Spiral turn, s = 100 mm editor@iaeme.com

4 Figure 1 Basic dimensions of Spiral resonator 2.2. Design of Chamber Separator: Major Diameter of the chamber separator disk = 68 mm, Minor Diameter of the chamber separator disk = 30 mm, Thickness of disc = 10 mm, Number of discs = editor@iaeme.com

5 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube Figure 2 Basic dimensions of Chamber Separator Design of Perforated Tube Internal Diameter = 70 mm, Diameter of the perforated holes = 8 mm External Diameter = 72 mm, Length of the tube = 400 mm Figure3 Design of Exhaust Perforated Tube editor@iaeme.com

6 Figure 4 Design of Exhaust Perforated Tube 2.4. Design of silencer shell Diameter = 80 mm, Thickness=4mm, Length of the tube = 400 mm Figure 5 Design of Silencer editor@iaeme.com

7 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube Figure 6 Design of Perforated Tube 2.5. Design of Plate External Diameter = 84 mm, Internal Diameter = 30 mm, Thickness = 4 mm Figure 7 Design of Plate 3. COMPUTATIONAL FLUID DYNAMICS & FLOW ANALYSIS Computational Fluid Dynamics also generally called CFD is an important branch of fluid mechanics and it uses numerical methods and algorithms to analyse and solve fluid flow problems. It has become popular since the previous methods, experimental and theoretical are either very expensive, time consuming, or involve too much labour. In CFD, computers are used to solve the algorithms that define and analyse the fluid flow. Due to the increase in the computational capabilities over time and better numerical solving methods, most experimental and theoretical work has been done using CFD. It is not only cost effective but it helps one analyse and simulate complex geometries, heat transfer, and shock waves in a fluid flow. It also helps solve partial differential equations (PDE) of any order in a fluid flow. This mainly helps analyse the internal or external fluid flow. The use of CFD has become increasingly popular in branches of engineering such as Aerospace to study the interaction of the editor@iaeme.com

8 propellers or rotors with aircraft fuselage, Mechanical to obtain temperature distribution of a mixing manifold, Bio-medical engineering to study the respiratory and circulatory systems. Figure 8 Processes of CFD and FEA 4. FEA SOFTWARE There are many FEA software s available in the market. Some of them mostly used in Industry are ANSYS, ANSYS WORKBENCH, MSC NASTRAN and ABACUS.Apply Mesh Controls/Preview Mesh: Meshing is the process in which geometry is spatially discretized into elements and nodes. This mesh along with material properties is used to mathematically represent the stiffness and mass distribution of your structure. Model is automatically meshed at solve time. The default element size is determined based on a number of factors including the overall model size, the proximity of other topologies, body curvature, and the complexity of the feature. If necessary, the fineness of the mesh is adjusted up to four times (eight times editor@iaeme.com

9 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube for an assembly) to achieve a successful mesh. If desired, preview of the mesh is available before solving. Mesh Controls: When in Simulation, your part or multi body part is automatically meshed at solve time. The default element size is determined based on the size of the bounding box, which is the smallest box that the part or assembly will fit in, as well as the proximity of other topologies, body curvature, and the complexity of the feature. If necessary, the fineness of the mesh is adjusted up to four times (eight times for an assembly) to achieve a successful mesh using the assembly's bounding box first, then the part's bounding box in the second pass. Define Analysis Type: We can choose the analysis type based on the loading conditions and the response we wish to calculate. For example, if natural frequencies and mode shapes are to be calculated, would choose a modal analysis. There are several types of analyses we can perform in Simulation. The primary differences are in the specific types of loads that we apply and results that review. Establish Analysis Settings:Each analysis type includes a group of analysis settings that allow defining various solution options customized to the specific analysis type, such as large deflection for stress analysis. 5. ANALYSIS OF SILENCER Figure 9 Meshing of silencer 6. PROBLEM SETUP AND SOLUTION The mesh was checked. The analysis type was changed to density based type and the velocity formulation was changed to absolute. Time was changed to transient state. Models and location of receivers: Energy was set on position and viscous model selected is LES model. Subgris scale model is Smagorinsky-Lily sub model. For enabling LES model in 2-D, a TUI command is to be used. The command is (rpsetvsr les2-d? #t). Ffowcs-Williams& Hawking s acoustics model is used. The source of sound and receivers are specified. Direction Distance from Inlet (mm) Y 100 Y 200 Y 350 Y 440 Y The receivers are placed at inlet of the silencer and the distances are mentioned are above. This distance is selected so that the source becomes a point source and a distribution of acoustic pressure level does not change with angle of measurement. Materials: Air (ideal gas) as fluid and stainless steel as solid was selected from the fluent database by clicking change/create. Properties given for the used fluid are: Density : ideal gas density Specific heat : 1006 j/kg-k (constant) editor@iaeme.com

10 Thermal conductivity : W/m-K (constant) Viscosity : e-05kg/m-s (constant) Cell zone conditions The interior of the nozzle is assigned as fluid. Different boundary conditions were applied for different zones. The boundary conditions are below Type of Boundary Location Value Condition Inlet Pressure-inlet pa Outlet Pressure-outlet 0.0pa Inlet Temperature 623 k Solution methods: The solution methods were set as follows 1. Formulation =implicit 2. Flux type =Roe-FDS 3. Gradient=least square cell based 4. Flow=second order upwind 5. Transient formulation=second order implicit Initialization Hybrid initialization is done. Convergence criteria The convergence criteria were set to 10-4 Run calculationtime step size = 1s Number of time steps=500 Number of iterations per time step= EXPERIMENTAL SET-UP & PROCEDURE (METHODS) The details of the experimental set up are presented in this chapter the alternations made to the instrumentation are also described.the experimental setup is fabricated to fulfil the objective of the present work. The various components of the experimental set up including modification are presented in this chapter. The silencer existed and new designed silencer is fixed to the bike in below. The experimental set-up consists of spiral resonator, perforated tube diameter 700mm, chamber separator, divergent, perforated tube of diameter 30mm, and cylinder shell. Before starting the engine, the existing silencer is separated from the engine. The designed silencer is fitted correctly. Then the decibel meter is placed at distance of 1900mm. The engine is allowed to run for 1 minute, so that it can get steady conditions are attained. The various steps involved in the setting of the experiments are explained below 1. The Experiments were carried out after installation of the silencer. 2. Precautions were taken, before starting the experiment. 3. Always the engine was started with no load condition 4. The readings such as decibels are to be noted at intervals. 5. After completion of test, the load on the engine was completely relieved, then the engine was stopped. Finally the results were noted editor@iaeme.com

11 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube Figure 10 (A) Bike with Existing Silencer 8. RESULTS Figure 10 (B) Bike with New Designed Silencer 8.1. The Temperature Distribution over Silencer Figure 11 Temperature Distributions Over Silencer 8.2. The noise developed at different locations in the simulation areas follows

12 Figure 12(A) (SPL / St no) Receiver-1 Graph Figure 12(B) (SPL / St no) Receiver-2 Graph Figure 12(C)(SPL/St no) Receiver-3 Graph Figure 12(D)(SPL/Stno) Receiver-4 Graph editor@iaeme.com

13 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube Figure 12(E)(SPL / St no)receiver Graph 8.3. The noises developed at outlet in existing silencer areas follows Figure 13(A)Decibels of existing silencer Figure 13(B)Decibels of Experimental(New) Silencer editor@iaeme.com

14 9. CONCLUSIONS The results obtained from simulation(refer fig.12) are at 100mm distance from inlet of silencer, the sound pressure level is dBA.From 200mm distance from inlet of silencer, the sound pressure level is dBA. From 350mm distance from inlet of silencer, the sound pressure level is 95.12dBA. From 440mm distance from inlet of silencer, the sound pressure level is 84dBA. From 18728mm distance from inlet of silencer, the sound pressure level is 73.24dBA.From result of simulation, it has been concluded that the silencer design has the lowest sound pressure level of 73.24dBA is generatedexperimental testing for new designed silencer is 1900mm distance from outlet of silencer, the sound pressure level is 69 dba. From experimental test (refer fig.13), it was concluded that there is decrease of sound pressure level about 7 dba from existing silencer to new designed silencer. 10. FUTURE SCOPE Future experiments can be done with the addition of glass wool to the silencer. Experiments can be extended with addition of multi tubes with this new design. With above modification this silencer can be fitted to the sports bike to test the sound level also. The future research of sound transmission and absorption can be done with bio-based materials, wood plastic composites and carbon name tubes (CNT) also. REFERENCES [1] G. W. Stewart, Acoustic waves filters, Physics Review 20, 1922, [2] D. D. Divis, Jr. G.M. Stokes, D. Morse, and G.L. Stevens, Theoretical and Experimental Investigation of Muffler with Comments on Engine- Exhaust Muffler Design,1954,NACA [3] J. Igarashi and M.Toyama, Aeronautical Research Institute, Fundamental of Acoustical Silencers. University of Tokyo, 1958,Report no.339, [4] M. L. Munjal, A.V. Sreenath and M. V. Narasimhan.Velocity ratio in the analysis of linear Dynamical System. Journal of sound and Vibration 26, 1970, [5] M. L. Munjal Velocity Ratio Cum Transfer Matrix Method for the Evaluation of Muffler with Neon Flow.Journal of sound and Vibration 39, (1975), [6] C. I.J. Young and M. J. Crocker(1975).Prediction to Transmission loss in Mufflers by Finite Element Method.Journal of Acoustical Society of America 57, [7] A.K.M. Mohumuddin, Mohd Rashidin Ideres and Shukari Mohad Hashim, Experimental Study of Noise and Back Pressure For Silencer Design Characteristics, Journal Of Applied Science5 (7): , 2005, ISSN [8] S. N.Y. Gerges and R. Jordan, F. A. Thieme, J. L. Bento Coelho, J. P. Arenas,Muffler Modeling by Transfer Matrix Method and Experimental Verification, J. of the Braz. Soc. of Mech. Sci. &Eng, 132 / Vol. XXVII, No. 2, April-June [9] Reza Kashani and Jeff Monfort, Low-Frequency Thermoacoustic Instability Mitigation Using Adaptive-Passive Acoustic Radiators. ASME 2011 Turbo Expo, Paper No. GT , PP , 2011, DOI: / GT [10] Yasuda, T., Wu, C., Nakagawa, N., Nagamura, K. (2013).Studies on an automobile muffler with the acoustic characteristic of low-pass filter and Helmholtz Resonator. Applied Acoustics, vol. 74, no. 1, p ,2013. [11] Mr. Jigar H. Chaudhari, Muffler Design for Automotive Exhaust Noise Attenuation - A Review, Int. Journal of Engineering Research and application, ISSSN: ,2014, Vol. 4, PP editor@iaeme.com

15 Noise Reduction of Two Wheeler by Redesigning Spiral Resonator & Perforated Tube [12] Ehsan Sabah M. AL-Ameen, Experimental Test for Noise Attenuation in Gasoline Engine with Different Types of Mufflers.Journal of Engineering and Development.Vol.16, No.4, 2013, ISSN [13] Wei-hongtan, Zaidimohdripin, Analysis of exhaust muffler with micro-perforated panel, Journal of VIbroEngineering. Volume 15, Issue 2. ISSN , 2013, PP [14] Bin Li1, Jeong HoYouand Yong-Joe Kim,Low frequency acoustic energy harvesting using PZT piezoelectric plates in a straight tube resonator. IOP PUBLISHING, Smart Mater. Struct. 22, 2013, (9pp). [15] M. L. Munjal, Recent Advances in Muffler Acoustics. International Journal of Acoustics and Vibration. Vol. 18, No. 2, 2013, PP [16] Munjal, M.,Acoustics of Ducts and Mufflers with Application,Exhaustand Ventilation System Design. John Wiley & Sons, 2013, New York. [17] Yu, X., Cheng, L., Duct noise attenuation using reactive silencer with various internal configurations. Journal of Sound and Vibration. vol. 335, 2015, PP [18] Jesus Madrigal-Melchor, Agustin Enciso-Munoz, David Armando Contreras- Solorio,Xochitl Saldana-Saldana, Raul Alberto Reyes-Villagrana, A New Alternative Method for the Generation of Acoustic Filters, Modulating Acoustic Impedance: Theoretical Model. Open Journal of Acoustics, 2017, ISSN Online: editor@iaeme.com