(117c) Experimental Study on Flow Characterization in a Rectangular Spouted Bed By Image Processing

Jingsi Yang ^a, Ronald W. Breault ^b*, Steven L. Rowan ^a, Justin M. Weber ^b

^a Oak Ridge Institute for Science and Education, 3610 Collins Ferry Road, Morgantown, WV 26505, United States

^b National Energy Technology Laboratory, U.S. Department of Energy, 3610 Collins Ferry Road, Morgantown, WV 26505, United States

*Corresponding author: E-mail address: ronald.breault@netl.doe.gov (R. W. Breault)

Abstract

In this study, a systematic image processing procedure is applied to characterize gas-solid flow under different operating conditions in a 30.2 mm × 101.6 mm rectangular spouted bed. Nozzle size, static bed height, and superficial gas velocity are investigated as influence factors. By applying image adaptive threshold and logical operation, the original color images are transformed into binary images exhibiting detailed boundary information. To analyze the binary image by means of a self-developed algorism and mask processing, the bed height can be determined, through which the variation of the bed expansion ratio with superficial gas velocity can be obtained. In combination of image dilation and erosion operations, the contour and bounding box of the gas jet can be identified accurately, from which the jet vertical height and the jet area can be calculated. An equivalent diameter, calculated by the number of pixels occupied by the jet image, is introduced to characterize the jet size. Furthermore, an equivalent jet voidage is calculated by dividing the total number of pixels belongs to the air with the total number of pixels in the entire jet image. Based on statistical analysis of obtained images, the variation of jet size and equivalent voidage with the three influence factors mentioned above will also be discussed. The current study highlights the application of image analysis in investigating the flow characterization and obtaining more hydrodynamic information in a rectangular spouted bed.

Keywords: Image processing; Bed expansion ratio; Jet size; Jet voidage; Rectangular spouted bed