Noise Reduction Techniques
Noise is a critical metric in many applications:
● Sources of Noise:
o Blade turbulence
o Motor and bearing harmonics
o Structural vibration
Mitigation Strategies:
● PWM control for optimized RPM
● Aerodynamically shaped blades
● Anti-vibration mounts and dynamic balancing
● Use of acoustic isolation chambers
For calculating combined noise for 2 sources with the same noise magnitude you can use the tomb role and just add 3DBA. For more sources or where you have different noise magnitudes to be added you can use the following formula:
L1,L2... are the different noises where Ltotal is the combined noise level.
Countermeasures:
● Increase fan speed (within thermal/mechanical limits)
● Use larger diameter impellers
● Optimize ducting to maintain flow efficiency and backpressure
● Select high-efficiency blade profiles to compensate for reduced density