HVAC Blower: A Steady State RANS Noise Prediction Method

In an ever-transforming sector such as that of private road transport, major changes in the propulsion systems entail a change in the perception of the noise sources and the annoyance they cause. As compared to the scenario encountered in vehicles equipped with an internal combustion engine (ICE), in electrically propelled vehicles the heating, ventilation, and air conditioning (HVAC) system represents a more prominent source of noise affecting a car’s passenger cabin.By virtue of the quick turnaround, steady state Reynolds-averaged Navier Stokes (RANS)- based noise source models are a handy tool to predict the acoustic power generated by passenger car HVAC blowers. The study shows that the most eminent noise source type is the dipole source associated with fluctuating pressures on solid surfaces. A noise map is generated from the noise source models data, giving indications of how changes in operating conditions affect the acoustic output of the machine throughout its operating range. The capability to predict power spectra with steady state RANS is investigated, and the overall sound power level of several operating points is validated against experimental data, showing good match.The study aims at establishing steady state RANS noise source models as a valuable tool in preliminary acoustic analyses of HVAC blower designs, in particular in the early stage of new design studies, thus helping the industry to better target quieter operation and enhanced passenger comfort.