Vortex-Control Notches

AAO Frame

Our AAO (Advanced Acoustic Optimisation) frames feature integrated anti-vibration pads as well as our proprietary Stepped Inlet Design and Inner Surface Microstructures, both of which further refine the fan’s performance/noise efficiency.

Anti-Stall Knobs

The NF-S12A’s Anti-Stall Knobs reduce flow separation phenomena in medium to high impedance situations and thereby increase the fan’s stall margin. This means that the NF-S12A is even more versatile than its renowned predecessor and can achieve better performance on heatsinks and radiators.

Bevelled Blade Tips

Reducing critical rotor stator interaction, the NF-S12B's and NF-B9's Bevelled Blade Tips permit to combine a higher blade surface area with quieter operation and thus form a cornerstone of the fans' outstanding efficiency.

Flow Acceleration Channels

By speeding up the airflow at the crucial outer blade regions, Flow Acceleration Channels reduce suction side flow separation and thus lead to better efficiency and lower vortex noise.

Focused Flow™ Frame

Designed for pressure demanding applications such as heatsinks and radiators, the Focused Flow™ frame features eleven stator guide vanes that straighten, channel and focus the airflow, which allows the NF-F12 to rival the performance of conventional fans running at much faster speeds.

Inner Surface Microstructures

With the tips of the fan blades ploughing through the boundary layer created by the Inner Surface Microstructures, flow separation from the suction side of the blades is significantly suppressed, which results in reduced blade passing noise and improved airflow and pressure efficiency.

Metal bearing shell

In order to guarantee the highest possible degree of manufacturing precision, minimum tolerance and excellent long-term stability, our newest 120 and 140mm fans sport a CNC milled bearing shell made entirely from brass.

Custom-designed PWM IC with SCD

Our custom-designed NE-FD1 PWM IC integrates our Smooth Commutation Drive (SCD) technology. By providing smoother torque impulses, SCD suppresses PWM switching noises and thus makes the fan quieter at low speeds.

Smooth Commutation Drive

The latest version of our advanced Smooth Commutation Drive system ensures superb running smoothness by eliminating torque variations and switching noises. This makes our fans remarkably quiet even at very close distances.

SSO-Bearing

Combining the proven concept of hydrodynamic bearing with an additional magnet that supports the self-stabilisation of the rotor axis, our time-tested SSO-Bearing technology has become synonymous with supremely quiet operation and exceptional long-term stability.

SSO2 Bearing

SSO2 is the further optimised second generation of our renowned, time-tested SSO bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilisation, precision and durability.

Stepped Inlet Design

Our Stepped Inlet Design adds turbulence to the influx in order to facilitate the transition from laminar flow to turbulent flow, which reduces tonal intake noise, improves flow attachment and increases suction capacity, especially in space restricted environments.

Vortex-Control Notches

Vortex-Control Notches split up trailing edge vortices and thus spread the fan’s noise emission over a wider range of frequencies. This measure makes the fan sound more pleasant to the human ear.

Sterrox® liquid-crystal polymer (LCP)

Noctua’s novel Sterrox® liquid-crystal polymer (LCP) compound features extreme tensile strength, an exceptionally low thermal expansion coefficient and dampening characteristics that are ideal for reducing resonance and vibration phenomena in advanced fan-blade designs.

Vortex-Control Notches

Employing advanced noise-reduction techniques like Bevelled Blade-Tips and Vortex-Control Notches, the NF-B9's highly-optimized blade design provides superior pressure and airflow performance at extremely low noise levels.

By increasing the distance between the impeller and the frame at the outermost areas of the fan where the impeller achieves the highest velocities, bevelled blade tips help to reduce critical rotor-stator interaction. This measure makes it possible to combine the large blade surface area and high profile chord length of a high-output blade geometry with excellent quietness of operation.

Basically, an increase in static pressure usually brings about higher noise emissions. In the case of the NF-B9, this problem is dealt with by adding Vortex-Control Notches to the blades' trailing edges. Due to the two notches at the trailing edge, the flows along the suction and pressure side mix more smoothly. This allows for less turbulence and velocity loss, which leads to a significant reduction in noise emission as well as increased efficiency. In order to achieve the smoothest possible transition and maximum noise reduction, the Vortex-Control Notches are rounded in shape.

In addition to optimizing the joining of the flows at the trailing edge, the Vortex-Control Notches fulfil the task of psychoacoustic optimization: Due to the Vortex-Control Notches, trailing edge vortices are split up into several smaller vortices. Thus the noise is spread over a wider range of frequencies and therefore perceived as much less annoying.