Gas-liquid slug flow in micro/millimeter-scale channels is attractive in a broad range of applications because of its high mass and heat transfer rates [1][2]. In almost all applications, the sizes of slugs need to be known precisely, since the mass transfer characteristic depends on the slug length and velocity [1]. To estimate the slug length from design and operating conditions or efficiently design devices that can generate slugs with a desirable size, a number of models have been developed so far for micro/millimeter-scale T-shaped channels, which are often used as generators of gas-liquid slugs, but parameters of such models need to be empirically determined through many experimental trials [3]. To reduce the experimental efforts, the physically sound model has been developed [4] but are limited to micrometer-scale T-shaped channels. In this study, the applicability of the existing physically sound model is experimentally investigated in the case of millimeter-scale T-shaped channels under various channel sizes, flow rates, and channel materials. The results show that the estimation accuracy of the existing model deteriorates when the feed flow rate ratio of gas to liquid becomes small and when the channel width ratio of the gas to the liquid flow becomes small. Taking these results, the combination of physical and empirical models is newly developed. Our developed model will ensure the high accuracy in the design of the millimeter-scale T-shaped channels with gas-liquid slug flows.
[1] G. BerÄiÄ and A. Pintar, “The role of gas bubbles and liquid slug lengths on mass transport in the Taylor flow through capillaries,†Chem. Eng. Sci., vol. 52, no. 21–22, pp. 3709–3719, 1997.
[2] G. Dummann, U. Quittmann, L. Groschel, D. W. Agar, O. Worz, and K. Morgenschweis, “The capillary-microreactor: A new reactor concept for the intensification of heat and mass transfer in liquid-liquid reactions,†Catal. Today, vol. 79–80, pp. 433–439, 2003.
[3] P. Garstecki, M. J. Fuerstman, H. A. Stone, and G. M. Whitesides, “Formation of droplets and bubbles in a microfluidic T-junction - scaling and mechanism of break-up, †Lab Chip, 6 pp. 437-446, 2006
[4] V. van Steijn, C. R. Kleijn, and M. T. Kreutzer, “Predictive model for the size of bubbles and droplets created in microfluidic T-junctions.,†Lab Chip, vol. 10, no. 19, pp. 2513–2518, 2010.
