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Evaporating Thin Film Flow Field Mapping - Molecular Fluorescence Velocimetry (MFV)

Molecular Fluorescence Velocimetry (MFV) system has been developed to use for meso- to micro-scale flow fields, such as evaporating thin film of a capillary meniscus flow. The system uses caged molecular fluorescent probes of less than 10 nm in size for tracking particles, whose low photo affinity with non-fluorescence emission until UV light make them uncaged to a higher photon affinity to fluorescence. A very thin and distinct fluorescence line is marked in the flow field by a pulsed UV source, and this tagged fluorescence line is tracked to evaluate the Lagrangian velocity profiles. The MFV technique has shown a potential advantage in using for micro-scale thermal flow applications.

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Thin Film Thickness Contour Mapping - Fizeau Fringes Interferometry

Micro heat transport devices such as Capillary Pumping Loops (CPLs) and heat pipes have capillary meniscus developed in the evaporator. The evaporating film thickness profile is essential to know to understand the fundamental fluid physics and heat transfer phenomena. Fizeau Fringes Interferometry has been implemented and used to measure the thickness of evaporating thin film of a capillary meniscus. The developed system utilizes a monochromatic light, a microscope and a tilted plate meniscus test cell. The thickness of evaporating thin film is measured with resolution of  /4n. When white light is used, the slope of thin film can also be determined by the rainbow fringes that change their R-Y-G-B order depending on the slope.

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Micro Scale Electroosmotic Flow Measurements - Micro-PIV

Electroosmosis is the flow produced by the action of an electric field on a fluid with a net charge, which is created by the surface Zeta potential and confined in the Debye layer. This classical phenomena of electroosmosis reclaims its importance in devising a pumping means for micro-channel flows occurring in a wide range of MEMS devices. Using the micro-PIV and molecular tagging fluorescence velocimetry techniques, electroosmotically driven flows in various micro-channel configurations have been measured to examine their feasibility to use for micro-pumping and micro-valve applications.

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