# Aeration Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Aeration Number, abbreviated as $$N_a$$, a dimensionless number, is used for the agitated mixing of gas and liquids.

## Aeration Number formula

$$\large{ N_a = \frac{ Q }{ n \; d^3 } }$$
Symbol English Metric
$$\large{ N_a }$$ = Aeration number $$\large{dimensionless}$$
$$\large{ Q }$$ = volumetric flow rate of gas $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$
$$\large{ n }$$ = rotational speed $$\large{\frac{deg}{sec}}$$ $$\large{\frac{rad}{s}}$$
$$\large{ d }$$ = diameter of impeller $$\large{in}$$ $$\large{mm}$$