Flow noise mitigation in a complex aftertreatment system through a hybrid computational aeroacoustics methodology Politecnico di Torino

Format:

Book

Conference/Event

Author/Creator:

Millo, Federico, author.

Contributor:

Arina, Renzo

Benetti, Antonio

Bianco, Andrea

Moratti, Monica

Peiretti Paradisi, Benedetta

Reviglio, Annalisa

Sapio, Francesco

Conference Name:

15th International Conference on Engines & Vehicles (2021-09-12 : Capri, Italy)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2021

Summary:

Flow noise produced by the turbulent motion of the exhaust gases is one of the main contribution to the noise generation for a heavy-duty vehicle. The architecture of the aftertreatment must be optimized since the early design phases of an engine to improve the Noise Vibration Harshness (NVH) performance and fulfill the imposed noise limits. In this context, a reliable Computational Aeroacoustics (CAA) methodology could be employed to evaluate the impact of different noise mitigation strategies. 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 carried out with the code STAR-CCM+ gives an analysis on the flow inside the diffusor of the exhaust system with a RANS approach and it provides the turbulence intensity distribution necessary to localize and quantify the noise sources in the second step. The SNGR method, implemented in the acoustics software Actran, is employed to synthetize the noise sources for the subsequent computation of the radiated acoustic field. To assess the reliability of the coupled approach, a necessary sensitivity analysis on the far field noise to the method parameters was performed, especially on the noise source extension. In addition, the baseline design of the exhaust system was also tested with a Direct Noise Calculation (DNC) providing absolute flow noise levels to assess the results obtained by the hybrid CAA approach. Then, the modified version of the exhaust diffusor was analysed with the fast approach of the proposed coupled methodology, confirming the noise attenuation in the new design configuration. The adoption of an SNGR method drastically downscales the computational cost of a CAA simulation and becomes fully compatible with an industrial process of evaluation for a new product design

Notes:

Vendor supplied data

Publisher Number:

2021-24-0091

Access Restriction:

Restricted for use by site license