Aero-acoustic optimization of flow-induced noise through biomimetic serrations on Automotive HVAC system components

The present work studies the effect of Owl Wing feather inspired Leading-edge serrations for minimizing Aero-Acoustic Noise. The aim of this research was to systematically study the effect of serrations by applying Box–Behnken experimental design for modeling the varied serrations in the Heating, ventilating and air conditioning (HVAC) system vent blade geometry. The variables of the serration model studied were Serration Height, Serration Thickness, Serration Spacing and the combination effect of variation in number of serrations. The Sound Pressure Levels at 1/3rd Octave bands in the Audible range of 800Hz to 4000Hz were studied and the Response Surface Response surface methodology approach was used for optimization of the process parameters and identifying the optima geometry parameters. An Optimized Geometry with 6 Serrations was found to have significant improvement in comparison to the No Serration base geometry. These results were further improved by Increasing the Maximum number of possible serrations from 9 to 16. The effect of these selected geometries in noise reduction at different octave bands was verified through further Experimental Trials. This study proved that Box–Behnken design and Response Surface Methodology could efficiently be applied for minimizing the Sound Pressure Level.