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arXiv · 2611.08552

An Analytical Model for Laser-Activated Two-Phase Choking and Microfluidic Suction on Surface Boundary Layers

D. Tsiklauri
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Abstract

We present a predictive fluid mechanics model to calculate pressure drops (0.25 atm) and fluid velocities (2.50 m/s) governed by localized phase change and choking phenomena in a capillary-constrained, coaxial microfluidic actuator. Driven by near-infrared thermal absorption, the analytical framework describes how energy deposition drives vapor cavity growth and subsequent cavitation bubble collapse, inducing a transient suction force across a curved, two-radii Young-Laplace capillary boundary. Velocity drops are derived from closed-form analytical equations that explicitly couple vapor volume dynamics with non-linear flow area restriction and fluid drag. The model predicts a maximum boundary layer wall shear stress of 30.06 Pa at the target interface. Crucially, this shear magnitude matches the physical threshold required to mechanically strip surface contaminant boundary layers while remaining below the damage threshold of underlying target substrates. Finally, we formulate a closed-form expression for the maximum allowable liquid inlet temperature required to prevent thermal saturation and sustain stable, continuous microfluidic suction cycles. These equations establish direct engineering design rules for optimizing phase-change microfluidic actuators and next-generation coaxial fluidic systems.

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D. Tsiklauri. 2026-11-05. An Analytical Model for Laser-Activated Two-Phase Choking and Microfluidic Suction on Surface Boundary Layers. https://arxiv.org/abs/2611.08552

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