Bevelled Blade Tips
Bevelled Blade Tips
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.
.jpg)
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.
.jpg)
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.
Related articles
Want to know more on this topic? Explore relevant articles and resources.
G2 fan series aerodynamic innovations
Building on the technological innovations of the NF-A12x25, the G2 models represent a further refined, second-generation implementation of this design approach.
NF-A12x25: interview with Lars Strömbäck (Noctua CTO)
The NF-A12x25 took over four years to develop, pushing Noctua’s R&D to new heights. Noctua’s CTO shares the innovations that make it a breakthrough in fan design.
NF-A12x25: technical backgrounds and manufacturing challenges
From material limitations to microscopic tolerances, the NF-A12x25 was one of Noctua's most challenging projects to date. But how did they overcome these obstacles?
Flow Acceleration Channels
Flow Acceleration Channels speed up airflow at blade edges, reducing flow separation, vortex noise, and improving airflow efficiency.