

:: Section 9Inertial Impaction
IV. Calculation of Cutoff SizeOnce Stk_{50 }is available, we can calculate the cutoff size as: Since C_{c} is a function of d_{p}, d_{p}_{50} 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:
