D214 大口径管内における気泡流のダイナミクス(OS12 温暖化対策とCO2削減技術)

概要

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In order to clarify the characteristics of bubbly flows, we researched the fluctuation of bubbly flow in a large diameter pipe of 400 mm in diameter and 2000 mm in height. The acrylic pipe with water jacket was filled up with water, and bubbles were generated via perforated plate. We employed Four-Tip Optical-fiber Probe (F-TOP) to measure the equivalent bubble diameters, bubble velocities and time-series void fractions. On the basis of the experimental results, we proposed a newly developed method to extract the long-period fluctuations from point-wise void fractions. Analyzing time-series point-wise void fractions measured via F-TOP, we demonstrate the long-period fluctuations are extracted via wave form analysis. As a result, we confirmed that the structure of the bubbly flows has the transition from inhomogeneous structure into homogeneous structure with respect to height. Furthermore, we obtained the correlation between the time-series void fractions and visualization results of the bubbly flows.
2009-06-28