Visualization of diffusion mixing in a micro-mixer with flow paths fabricated by photolithography

Toshiyuki Horiuchi; Yuta Morizane

doi:10.1117/12.2272903

5 September 2017 Visualization of diffusion mixing in a micro-mixer with flow paths fabricated by photolithography

Toshiyuki Horiuchi, Yuta Morizane

Proceedings Volume 10372, Material Technologies and Applications to Optics, Structures, Components, and Sub-Systems III; 1037206 (2017) https://doi.org/10.1117/12.2272903
Event: SPIE Optical Engineering + Applications, 2017, San Diego, California, United States

Abstract

Mixing processes of two liquids were investigated by visualizing the mixing when they were simultaneously injected in a micro-mixer with lithographically fabricated Y-shape flow paths, and the mixing phenomena was analyzed in detail. To visualize the mixing, flows were observed by an optical microscope, and a clearly detectable chemical reaction was utilized. As the two liquids, a transparent aqueous solution of a strong alkali and a phenolphthalein ethanol solution were used. When they were simultaneously injected in Y-shape flow paths of a micro-mixer, they flowed at first in parallel along the joined path as laminar flows. This is because the Reynolds’ number became very small caused by the narrow flow-path widths of 50-100 μm. However, because two liquids were always contacted at the boundary, they were gradually mixed by diffusion, and the color of the mixed parts changed to vivid red. For this reason, it was able to measure the diffusion distance from the flow path center. Because the flow speeds were much faster than the diffusion speeds, the area colored in red did not depend on the time but depended on the distance from the joint point. It was known that the distance from the joint point corresponded to the time for mixing the liquids by the diffusion. It was clarified that the diffusion distance x was proportional to the square root of the diffusion time t or the distance from the joint point. The calculated diffusion coefficient D was (0.87-1.00)×10^-9 m²/s.

Conference Presentation

Citation Download Citation

Toshiyuki Horiuchi and Yuta Morizane "Visualization of diffusion mixing in a micro-mixer with flow paths fabricated by photolithography", Proc. SPIE 10372, Material Technologies and Applications to Optics, Structures, Components, and Sub-Systems III, 1037206 (5 September 2017); https://doi.org/10.1117/12.2272903

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available