Abstract: 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.

Abstract: 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.

Abstract: A high output fan assembly for cooling the radiator of a motor vehicle. The fan assembly comprises a shaft, first and second fans, and a motor. The first fan includes a plurality of first blades, each of which has an inner portion attached to the shaft, while an outer hub is attached to an outer portion of at least one of the first blades. The second fan includes a plurality of second blades, each of which has an inner portion attached to the outer hub. The motor is drivingly connected to the shaft to drive the first and second fans at the same number of revolutions per minute. The fan assembly is situated either for pulling or for pushing air across the radiator and an air conditioning condenser of the motor vehicle.