Anderson Cascade Impactors is designed to impinge air onto a metal collection plate at increasing velocities as the air travels through the impactor. In the initial stage of the impactor, where the velocity is the lowest only larger particles with more thermal momentum impact on the collection plates. As the velocity of the air impinging on the surface increases smaller and smaller particles are collected. The plates can then be weighed for mass of impacted particle or sent for HPL analysis.
Inspite of these impactors serving a relatively important roll in dry powder delivery research little work has been done to evaluate the ability of these impactors to differentiate between different particle size distributions of similar size. The goal of this work is utilize currently available computational tools to determine how much information can be be taken from the ACI devise. Special focus will be placed on what practical information can be derived from the output of the ACI test (mass on each stage).
In order to achieve this a computational model has been developed that closely matches real world ACI performance. Variable realistic PSD have been used as inputs and mass impaction is the model output. Various methods for inverting the output of the model back to an approximate PSD. These estimated PSD are then compared to the original input PSD and the method of inversion can be characterized for its accuracy.