Noise Generated by Low Pressure Axial Fans

End-plate for noise-by-flow control in axial fans

The paper presents a design procedure for anti-vortex endplates that are fitted to tip limited blades of the subsonic axial fans utilised in compact cooling units. The authors study the impact of tip leakage vortex bursting on the performance of the studied class of fans. The vortex breakdown occurs in the swirling flows at a blade’s tip, and is found to be a flow feature associated with the pr...

Synergistic Noise-By-Flow Control Design of Blade-Tip in Axial Fans: Experimental Investigation

Local improvement of flow and noise performances of axial-flow fans in a household refrigerator

In this paper, numerical and experimental investigations on an axial-flow fan with grooved/double-sectional blades are performed to improve its performance in terms of volume flow rate and noise at a local operating point. The target fan is used to cool a mechanical room of a household refrigerator. However, it is found that the target system has more resistance than that for which the fan is o...

Global Active Control Of Tonal Noise From Small Axial Cooling Fans

An active noise control system has previously been developed for the reduction of tonal noise radiated by small axial cooling fans, such as those found in desktop computers. This system uses four small actuators surrounding the fan in a mock computer casing. Due to industry volume constraints, a smaller fan and speaker configuration is desirable. If the smaller configuration is able to maintain...

Twin axial vortices generated by Fibonacci lenses.

Optical vortex beams, generated by Diffractive Optical Elements (DOEs), are capable of creating optical traps and other multi-functional micromanipulators for very specific tasks in the microscopic scale. Using the Fibonacci sequence, we have discovered a new family of DOEs that inherently behave as bifocal vortex lenses, and where the ratio of the two focal distances approaches the golden mean...