Aerosol Transport – Inertia

:: Section 9

Inertial Impaction

IV. Calculation of Cutoff Size

Once Stk₅₀ is available, we can calculate the cutoff size as:

Since C_c is a function of d_p, d_p50 cannot be obtained conveniently. Iteration is needed. i.e. assume a particle size, calculate its C_c, and compare the values on both sides of the equation. Repeat until both sides are equal.

Now, try some jet diameters and flow rates to design your impactor, and compare the cutoff sizes: