Inertial impactors have been used widely to measure the particle size distribution, analyze the chemical composition, and obtain the sample aerosol. A cavity plate was used as a inertial impaction plate to enhance the separation efficiency in this papar.. The separation efficiency of the conventional impactor and the cavity impactor was investigated for different Reynolds numbers.
The experimental results showed that the 50% cut-off aerodynamic particle diameter was smaller in the cavity impactor than in the conventional impactor because more particles were deposited in the cavity inner surface. Fine particle contamination and reentraunment were reduced in the cavity impactor. When Reynolds number increased, reentrainment was increased in the conventional inpactor, but it was decreased in the cavity impactor. The experimental results also showed that the cavity impaction plate could be used high temperature enviroment and bio aerosol sampling. Finally, the enhanced efficiency was obtained by using the cavity impaction plate due to the flow direction changes.
