FAN LAWS
The fan laws are a set of proportionalities relating each of the following parameters of airflow with fan speed (n), air density (ρ) and impeller diameter (d).
o Air pressure (p)
o Airflow quantity (Q)
o Power developed (Ppow)
Through extensive experimentation and derivation the following direct proportionalities have been arrived.
For varying speed but with constant air density and impeller diameter :
- Quantity varies directly as the speed
- Pressure varies as the square of the speed
- Power varies as the cube of the speed
- Efficiency is constant
For varying density but with constant speed and impeller diameter :
- Quantity remains constant
- Pressure varies directly as the density
- Power varies directly as the density
- Efficiency is constant
For varying impeller diameter but with constant speed and airdensity :
- Quantity varies as the cube of the impeller diameter
- Pressure varies as the square of the impeller diameter
- Power varies as the fifth power of the impeller diameter
- Efficiency is constant.
Comentários