The present invention is a system and method to significantly reduce noise associated
with air-moving devices such as an axial flow fan using a fan shroud and barrel
combination with built in silencers such as Helmholtz resonators. The invention
can be applied to a variety of applications such as a thermal management system
for a fuel cell powered vehicle. The resonator can be a hollow cavity in networks
attached to an outer or inner barrel or shroud and tuned to reduce noise at predetermined
noise frequency ranges within the airflow. The invention can also attach stator
members on the inner surface of the outer barrel to further reduce noise. Additional
sound absorbing material, such as steel wool, can be disposed within the resonator cavity.
