PD__BOOSTAcoustics_2010_06[1]

AVL – Advanced Simulation Technologies 2010 AVL List GmbH Hans-List-Platz 1, A-8020 Graz, Austria E-mail: ast@avl.com, http://www.avl.com AVL PRODUCT DESCRIPTION BOOST LINEAR ACOUSTICS Preprocessor showing the layout of a rock drill silencer model LINEAR ACOUSTICS Overview Advanced demands regarding acoustics within engine design projects can be covered by the linear acoustics module BOOST SID. This frequency domain solver is based on the Sound In Ducts (SID) code that has been developed and validated for a period of over ten years at KTH/MWL, Sweden. The linear acoustics solver is able to simulate the acoustics of intake and exhaust components and provides accurate predictions of • Transmission loss • Insertion loss • Noise reduction. The solver is extremely quick with individual models typically taking less than five seconds to generate the acoustic results. The existing Graphical Interface of BOOST is used to build and create the acoustic models. This means that the layout and connection of the model elements can be visualised in the same manner as other BOOST models. The program is available as • Standalone program • or as extension to BOOST Cycle Simulation Tool Advantages • Extremely fast • No detailed engine data necessary for boundary conditions • Smaller data sets required for model elements • End corrections and higher order modes included System Information p1 p2 q2 q1 Engine Exhaust system Termination The linear acoustics solver calculates in the frequency domain to determine the acoustic properties of a system. A model is made up of a source (an engine), a system (the exhaust line) and a termination (the tailpipe) Linear Acoustic Model The AVL BOOST-Linear Acoustics code uses the transfer matrix method. This compares two pairs of state variables, the temporal Fourier transforms of the acoustic pressure and sound volume velocity at the inlet and outlet of an element. The relationship between these two states, at a certain frequency f, can be described by a 2*2 complex matrix known as the Transfer Matrix ⎥⎦ ⎤⎢⎣ ⎡⎥⎦ ⎤⎢⎣ ⎡=⎥⎦ ⎤⎢⎣ ⎡ 2 2 MatrixTransfer 2221 1211 1 1 q p TT TT q p 43421 Capabilities • Pipes o Lined Duct o Perforated o Horn • Resonators o Quarterwave o Conical o Helmholtz • Restrictions o Expansion o Contraction • Aftertreatment o Catalyst o DPF • Plenums o Flush Eccentric o Extended o Concentric • User o Transfer Matrix o User Element o Lumped Impedance o Active Ports 2 AVL – Advanced Simulation Technologies 2008 AVL List GmbH Hans-List-Platz 1, A-8020 Graz, Austria E-mail: ast@avl.com, http://www.avl.com AVL – Advanced Simulation Technologies 2010 AVL List GmbH Hans-List-Platz 1, A-8020 Graz, Austria E-mail: ast@avl.com, http://www.avl.com AVL PRODUCT DESCRIPTION BOOST LINEAR ACOUSTICS Processing of Calculation Results Results are post-processed by the AWS Standard post-processor Impress Chart. The following results are available from the Linear Acoustics: • Transmission Loss TL • Insertion Loss IL • Noise Reduction NR • Positive Sound Pressure p+ • Negative Sound Pressure p- • Sound Pressure • Volume Flow • Sound Pressure Levels • Sound Power Tasks • sound engineering • noise reduction • layout of mufflers Papers ON EXTRACTION OF IC-ENGINE LINEAR ACOUSTIC SOURCE DATA FROM NON-LINEAR SIMULATIONS Hans Boden, KTH/AVE, Marcus Wallenberg Laboratory, Sweden Robert Fairbrother, Markus TonsaI, AVL List GmbH, Graz, Austria CSV11, St Petersburg, July 2004. LINEAR ACOUSTIC EXHAUST SYSTEM SIMULATION USING SOURCE DATA FROM NON LINEAR SIMULATION Robert Fairbrother, AVL List GmbH, Graz, Austria DEVELOPMENT OF A GENERIC 3D CELL FOR THE ACOUSTIC MODELLING OF INTAKE AND EXHAUST SYSTEMS Robert Fairbrother, Siwei Liu and Andreas Dolinar, AVL List GmbH, Graz, Austria Gianluca Montenegro and Angelo Onorati, Politecnico Di Milano, Milan, Italy, ICSV 16, Krakow 2009 Transmission loss for Muffler