AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Break-up and Bounce of TiO2 and Cu Agglomerates Due to the Inertial Impaction
MIKA IHALAINEN, Terttaliisa Lind, Tiina Torvela, Kari Lehtinen, Jorma Jokiniemi, Paul Scherrer Institut, Switzerland
Abstract Number: 330 Working Group: Aerosol Physics
Abstract Impaction behavior plays a significant role in areas of nanoparticle technology, such as powder processing, nuclear safety and health research. Whether the agglomerates adhere onto the surface, bounce and/or break-up during inertial impaction under certain conditions remains a question to be answered. For this purpose agglomerate impaction behavior was studied.
A combination of a single stage Micro Uniform Deposit Impactor (MOUDI) and a low pressure sampling chamber was used to carry out the impaction studies. TiO2 and Cu agglomerates were impacted onto an impaction plate located in the MOUDI. The particles which deposited onto the impaction plate were studied using a Transmission Electron Microscopy (TEM). The TEM-grid for this purpose was located on the impaction plate. The bounced particles were collected from the sampling chamber for analysis with the TEM and a Scanning Mobility Particle Sizer (SMPS). The following parameters of the TiO2 agglomerates were varied to find out how they affect the impaction behavior: the primary particle size, agglomerate size and degree of sintering.
Both the primary particle size and the degree of sintering affected the break-up and bounce of the TiO2 agglomerates. For instance, the geometric mean diameter (GMD) of the bounced particles increased as the primary particle size was decreased indicating that the degree of fragmentation decreased. The degree of fragmentation represents the fraction of the bonds between the primary particles of the intact agglomerate that break-up during the impaction. The degree of fragmentation of the bounced particles also decreased as the degree of sintering of the agglomerates was increased. Further data analysis will be carried out to estimate the mass based bounced particle fraction of the impacted particles. Preliminary results show that there were no bouncing or de-agglomeration with the copper agglomerates.