A novel imaging system for concurrent measurement of particle velocity and size distribution in a pneumatic suspension

There are many industrial and research based situations where the analysis of dynamic particles is of interest. In particular the measurement of pulverized fuel in power generation and the monitoring of environmental particulate contaminants are both topical and important. Both particle size and dynamic properties are required to be known but where both particulate quantity (solids concentration - derived from size and numbers data) and velocity are known important mass flow information - i.e. quantity over time - can be derived. The measurement of both quantities often requires the use of two different technologies and therefore two different instruments, leading to high cost and size, which can be prohibiting factors in industrial situations. These problems are avoided if both functions can be performed by one instrument. The authors have in the past developed an imaging based particle sizing instrument. The present paper presents a study into a new strategy, based on past work, which enables both particle size and velocity to be established using one imaging based system. The paper introduces a novel cross correlation strategy, based on dividing the image into overlapping zones, which overcomes problems observed with real industrial images. This strategy is tested with both simulated images and real industrial data and results are compared to more traditional cross correlation methods. Results are encouraging, showing that the new strategy gives good results that are comparable to more time consuming approaches, suggesting that the present method may result in a useful solution to a real industrial need.