Broadband Noise Source Models as Aeroacoustic Tools in Designing Low NVH HVAC Ducts

Computational Fluid Dynamics (CFD) is an integral part of product development at Visteon Climate Systems with a validated set of CFD tools for airflow and thermal management processes. As we increasingly build CAE capabilities to design not only thermal comfort, but quiet systems, developing noise prediction capabilities becomes a high priority.

Two Broadband Noise Source (BNS) models will be presented, namely Proudman's model for quadrupole source and Curle's boundary layer model for dipole source. Both models are derived from Lighthill's acoustic analogy which is based on the Navier-Stokes equations. BNS models provide aeroacoustic tools that are effective in screening air handling systems with higher noise levels and identifying components or surfaces that generate most of the noise, hence providing opportunities for early design changes.

In this paper, BNS models were used as aeroacoustic design tools to redesign an automotive HVAC center duct with high levels of NVH. The design direction suggested by BNS tools were later supported by physical test data. These models were found to be valuable and cost effective tools in providing reliable design direction early in the development cycle.