Exhaust manifold radiation in the 5 kHz range: prediction of structural and interior acoustic excitation noise radiation of an exhaust manifold - (PPT)

摘要

Vibro-acoustic response of an exhaust manifold up to 5kz predicted: Taking in account separated structural and acoustic effects; Based on a Test/CAE correlated exhaust structural model; Model correlation strategy validated; Good correlation level mainly on the upper part of the exhaust, most interesting for the vibro-acoustic study; Dynamic behavior of the exhaust manifold well predicted around 4kHz critical frequency for the vibration and noise level. For the prediction of the response from the interior pressure excitation, the acoustic source estimation process has been set-up; Acoustic source then updated and improved for: Temperature effect, Effect of excitations phase extended up to 4.5Kz; Possible causes for still existing difference Test-CAE: Structural coupling, Acoustic damping, e.g. inlet impedance, Additional excitation due to flow noise (all over domain); Response from the structural excitation shown to be dominant; Resulting noise peak at 4000 Hz shown to be related to vibration of upper manifold part.