Computational Aero-Acoustics Simulation of Compressor Whoosh Noise in Automotive Turbochargers

Abstract

<div class="section abstract"><div class="htmlview paragraph">The advent of Eco-Boost technology in gasoline engines creates new challenges that need to be addressed with innovative designs. One of them is flow induced noise caused by flow, entering the turbocharger, at off design operation. At certain vehicle operation conditions, the mass flow rate and pressure ratio are such that compressor wheel generates a broad band frequency noise caused by flow separation from blade surfaces, which is called ‘whoosh’ noise.</div><div class="htmlview paragraph">Flow bench and engine testing can be used to detect flow induced noise, but understanding the fundamental mechanisms of such noise generation is necessary for developing an effective design. This paper describes Computational Aero-Acoustic (CAA) analyses performed to study the effects of inlet condition on the whoosh noise. A 3D Computational Fluid Dynamics (CFD) simulation performed including the entire compressor wheel and volute. The wheel consisted of six main and six splitter blades.</div><div class="htmlview paragraph">Based on the CAE results, a Leading-Edge Step at the compressor inlet in conjunction with an Inlet Guide Vane (or swirl vane) (IGV) were proposed to lower whoosh noise. Effectiveness of such innovative design is demonstrated in experimental testing.</div></div>