This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Assessment of Flow Noise Mitigation Potential of a Complex Aftertreatment System through a Hybrid Computational Aeroacoustics Methodology
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 05, 2021 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
Flow noise produced by the turbulent motion of the exhaust gases is one of the main contributions to the noise generation for a heavy-duty vehicle. The exhaust system has therefore to be optimized since the early stages of the design to improve the engine’s Noise Vibration Harshness (NVH) performance and to comply with legislation noise limits. In this context, the availability of reliable Computational Aero-Acoustics (CAA) methodologies is crucial to assess the noise mitigation potential of different exhaust system designs.
In the present work, a characterization of the sound generation in a heavy-duty exhaust system was carried out evaluating the noise attenuation potential of a design modification, by means of a hybrid CAA methodology. In a first step, a steady state 3D-CFD simulation of the exhaust system in its baseline configuration was carried out with a RANS approach, to gather an analysis of the flow inside the diffusor and to obtain the turbulence intensity distribution necessary to localize and quantify the noise sources. Then, in a second step, the Stochastic Noise Generation and Radiation (SNGR) method was employed to synthetize the noise sources for the subsequent computation of the radiated acoustic field. A sensitivity analysis on the far field noise to the main method parameters was also performed, especially on the noise source region extension.
Moreover, the baseline design of the exhaust system was also studied with a Direct Noise Calculation (DNC) approach, providing absolute flow noise levels to be compared with the results obtained by the means of the hybrid CAA approach. Then, a modified version of the exhaust diffusor was analysed with the proposed hybrid CAA methodology, highlighting the impressive potential in terms of noise attenuation of the new design configuration.
The adoption of proposed hybrid CAA methodology was therefore demonstrated to allow a dramatic downscaling of the computational cost compared to DNC simulations, being fully compatible with the limited time available for the development of a new product in the automotive industry.
- Federico Millo - Politecnico di Torino
- Benedetta Peiretti Paradisi - Politecnico di Torino
- Francesco Sapio - Politecnico di Torino
- Renzo Arina - Politecnico di Torino
- Andrea Bianco - Powertech Engineering
- Antonio Benetti - CNH Industrial – IVECO – Medium Trucks
- Monica Moratti - CNH Industrial – IVECO – Medium Trucks
- Annalisa Reviglio - Cornaglia SpA
Data Sets - Support Documents
|Unnamed Dataset 1|
- Torregrosa , A.J. , Broatch , A. , Climent , H. , and Andrés , I. A Note on the Strouhal Number Dependence of the Relative Importance of Internal and External Flow Noise Sources in IC Engine Exhaust Systems J. Sound Vib. 282 3-5 2005 1255 1263 10.1016/j.jsv.2004.05.017
- Bailly , C. , Bogey , C. , and Marsden , O. Progress in Direct Noise Computation Noise Notes 9 3 2010 31 48 10.1260/1475-47184.108.40.206
- Schoder , S. and Kaltenbacher , M. Hybrid Aeroacoustic Computations: State of Art and New Achievements J. Theor. Comput. Acoust. 27 4 2019 10.1142/S2591728519500208
- Lighthill , M. On Sound Generated Aerodynamically I. General Theory Proc. R. Soc. London. Ser. A. Math. Phys. Sci. 211 1107 1952 564 587 10.1098/rspa.1952.0060
- Ffowcs Williams , J. and Hawkings , D.L. Sound Generation By Turbulence and Surfaces in Arbitrary Motion Roy Soc London-Philosophical Trans Ser A 264 1151 1969 321 342 10.1098/rsta.1969.0031
- Martínez-Lera , P. , Hallez , R. , Bériot , H. , and Schram , C. Computation of Sound in a Simplified HVAC Duct Based on Aerodynamic Pressure 18th AIAA/CEAS Aeroacoustics Conf 2012 10.2514/6.2012-2070
- Mazeaud , B. , Chronéer , Z. , Karlsson , M. , Yao , H.D. , et al. Application of SNGR Method to Compute Aero-Vibro-Acoustics of Heavy-Duty Rear-View Mirrors 25th AIAA/CEAS Aeroacoustics Conf. 2019 2019 10.2514/6.2019-2727
- Vizzini , S. , Knutsson , M. , Dybeck , M. , and Abom , M. Flow Noise Generation in a Pipe Bend SAE Technical Paper 2018-01-1525 2018 https://doi.org/10.4271/2018-01-1525
- STAR-CCM+ https://mdx.plm.automation.siemens.com/star-ccm-plus
- Actran https://www.mscsoftware.com/en-uk/product/actran-acoustics
- Millo , F. , Peiretti Paradisi , B. , Sapio , F. , Arina , R. et al. Development of a Numerical Methodology for the Assessment of Flow Noise in Complex Engine Exhaust Systems SAE Technical Paper 2021-01-1043 2021 https://doi.org/10.4271/2021-01-1043
- Krug , C. and Benetti , A. 2018
- Bailly , C. and Juvé , D. A Stochastic Approach to Compute Subsonic Noise Using Linearized Euler’s Equations 5th AIAA/CEAS Aeroacoustics Conf. Exhib 496-506 1999 10.2514/6.1999-1872
- Shih , T.H. , Liou , W.W. , Shabbir , A. , Yang , Z. et al. A New k-ϵ Eddy Viscosity Model for High Reynolds Number Turbulent Flows Comput. Fluids 24 3 1995 227 238 10.1016/0045-7930(94)00032-T
- Mesbah , M. , Meyers , J. , Baelmans , M. , and Desmet , W. Assessment of Different Parameters Used in the SNGR Method Proc. 2004 Int. Conf. Noise Vib. Eng. ISMA 389 402 2004
- Millo , F. , Peiretti Paradisi , B. , Sapio , F. , Arina , R. et al. Computational Aeroacoustic Analysis of Noise Mitigation Potential of Complex Exhaust Systems Internationales Stuttgarter Symposium 21 Springer 2021 https://doi.org/10.1007/978-3-658-33466-6_36
- Tennekes , H. and Lumley , J.L. A First Course in Turbulence The MIT Press 1972 10.7551/mitpress/3014.001.0001