Shape and Size Effects of Glass Mini-Channels on Infrared Sensors in Air–Water Two-Phase Flow

Abstract

AbstractMultiphase fluid flows occur in biomedical, chemical and process applications, refrigeration/air conditioning systems, and heat pipes. The design of mini/microreactor requires a thorough understanding of two-phase fluid flow behavior. In the present work, wall thickness and shape effects of mini-channels on irradiation behavior of infrared (IR) sensor during two-phase flow are experimentally studied. Based on the observations, a numerical model is developed using COMSOL Multiphysics package. The irradiation behavior of IR rays on test sections having various dimensional ratios and shapes (circular, square, and triangular) is analyzed for bubble and slug flow regimes with an IR transceiver circuit. Experiments are done in horizontal circular tubes of internal diameters—5.20, 3.50, and 2.50 mm and thickness—0.60, 0.60, and 0.30 mm, respectively, and a square channel of cross section—2 × 2 mm with 0.5 mm thickness. The size of the two-phase bubble and slug flow regimes recorded with high-speed photography employing image processing techniques is compared with change in current amplitude difference measured using infrared transceiver circuit. The results are in good agreement. The numerical model developed can be further used to design an array of IR sensors capable of detecting volumetric void fraction..KeywordsTwo-phase flowImage processingIR transceiverLiquid film thicknessCOMSOL