AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Measurement of Dust Dispersity by Shadowgraphy Method—Direct Image Particle Analysis (DIPA)
Seungkoo Kang, SHENG-CHIEH CHEN, Wing-Tak Lai, David Y. H. Pui, University of Minnesota
Abstract Number: 449 Working Group: Instrumentation and Methods
Abstract For measuring the size distribution of resuspended dust particles by dust dispersers, real-time sampling instruments are normally used. However, different instruments usually reported different size distributions for the same dust stream and most likely it was due to the different measurement principles of the instruments. Besides, the occurrence of particle transport loss during the sampling by the instruments can also alter the size distributions, especially, for the dust particles larger than 1.0 micro-meter. In this study, the noninvasive shadowgraph imaging technique was applied to measure the dust size distribution at the area of interest to avoid sampling errors caused by the transport loss. Besides, the 2-D images taken for the resuspended dusts were expected to directly have better and clearer morphology information than the embodied equilibrium optical or dynamic diameter by the real-time instruments. With the 8 and 29 Mpixel CCD camera equipped with a high magnification lens, monodisperse PSL particles of 1.0, 2.0, 4.0, 17.0, 26.0 micro-meter were first used to demonstrate the sizing accuracy of the measurement system. Then the validated system was applied to the size distribution measurements of polydisperse ISO 12103-1 A2 fine dusts from different dust dispersers, including ISO light duty injector and ISO heavy duty injector. This newly developed system was able to measure dusts as large as 500 micro-meter which was unlikely by the conventional optical particle counter and aerodynamic particle sizer. It was also observed the changes in size distribution of the A2 dusts generated by the ISO injectors operated at different mass feeding rates and supply pressures indicating one should consider the effect of the operation condition for determining the size distribution of dusts.