AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
A Filter Sensor for Determining the Fractal Dimension of Nanosized Agglomerates and Fibrous Carbon Nanotubes
SHENG-CHIEH CHEN, Jing Wang, Heinz Fissan, David Y. H. Pui, University of Minnesota
Abstract Number: 81 Working Group: Instrumentation and Methods
Abstract Filtration techniques are used to mitigate PM emissions. The removal efficiency is the function of filtration conditions (filter types and properties and face velocities) and particle properties (size, morphology, concentration, etc.). Therefore, there exists a possibility to utilize the filtration method to differentiate particle shape. It has been found that there was a significant penetration difference between spherical particles and open agglomerates with the same mobility diameter through 1 micro-meter pore diameter Nuclepore filter due to the elongated shape and the accordingly enhanced interception deposition of agglomerates. A modified capillary tube model has been developed to predict the penetration accurately for aggregates and agglomerates by our previous studies. In this study, 1 micro-meter Nuclepore filter was challenged by classified monodisperse nanoparticles with different fractal dimension (determined by DMA-APM method) and carbon nanotubes. The modified capillary tube model was used to estimate the interception length (or effective length) by assuming the diffusion and impaction efficiencies are known. Results show that the calculated effective lengths of MWCNTs with different mobility diameters were close to the average values determined by the SEM analysis. The comparison of penetration between different fractal dimension Ag particles and CNT showed the higher fractal dimension the higher penetration. The penetration difference was significant between these particles. Nuclepore filter with the modified capillary tube model could be a sensor for determining particle fractal dimension.