Vertical squeezing route taylor flow with angled microchannel junctions

• Main Authors: Lim, An Eng, Lam, Yee Cheong
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Mechanical engineering; Gas Flowrate; Junction Angles
• Online Access: https://hdl.handle.net/10356/160492
• Institution: Nanyang Technological University

Heretofore, the microchannel junction angle θ dependent behavior on Taylor flow with a vertical squeezing route lacks a comprehensive understanding. An experimental study was performed on the vertical squeezing route Taylor flow for θ = 20, 45, 90, 135, and 160° at different flow rates of helium (He) and ethanol. By employing extreme θ of 20 and 160°, an in-depth knowledge of the associated mechanics is gained. Through the formulated theoretical model, the sizes of the bubble and slug were predicted quantitatively for various fluid flow rates and θ, with good qualitative and quantitative agreement with experimental results. With increasing liquid or decreasing gas flow rate, all the employed junction angle channels had insensitive unit cell volumeVUvariation with flow rate changes because of the near cancellation of the effect of increased liquid slug volumeVSwith the effect of decreased gas bubble volumeVB. Using the 90° channel as the reference, the 20, 45, 135, and 160° channels generated largerVBandVSresulting in a largerVU. This is attributed to the wider junction widthWJwhen θ deviated from 90°. With the widerWJ, it produces a longer gas neck length that leads to a larger bubble lengthLBduring the blocking process. The longer time due to the slower squeezing rate from the widerWJresults inLBgrowth during the squeezing process. AsWJvalues of 20 and 160° channels are similar (similarWJfor 45 and 135° channels), parabolic (U-shaped) trends forVB,VS, andVUagainst θ were observed for the various fluid flow rates. The understanding gained may be exploited for precise bubble and slug generation control for targeted applications.