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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Visualization and Analysis of Heat and Mass Transfer with Chemical Reactions in Microchannels

Get access (open in a dialog) DOI: 10.1615/IHTC15.min.009380
pages 4961-4971

Resumo

Micro-sensing techniques of temperature and concentration are essential to investigate mixing, chemical reaction, and matter generation processes in micro-reactor technology. We have developed a simultaneous imaging method of the temperature and solute concentrations of aqueous solutions in microchannels using two different wavelengths in near-infrared (NIR); one is 1412 nm at which the absorbance is sensitive to the temperature of water and the other is 1442 nm at which the absorbance is insensitive to the temperature and dependent only upon solute concentrations. In this study, when two aqueous solutions of hydrochloric acid (HCl) and sodium hydroxide (NaOH) flow at a flow rate of 60 ?L·min-1 and merge in a Y-shaped channel with a depth of 0.5 mm, absorption variations at the two wavelengths are investigated. The absorbance difference images indicate that the concentrations ratio of the two solutions determine the merging condition. Particularly in the case that the molar fraction of hydrochloric acid is 0.67 (HCl:NaOH = 2 M : 1 M), an interface between the solutions is formed. The interface, however, disappears and mixture area appears at the other molar fractions. Also, the absorbance images is converted to solute concentration ones of HCl and NaOH by a multiple regression analysis on the absorbance difference spectra of the two solutions.