Single-pulse dynamics and flow rates of inertial micropumps

TL;DR

This study investigates the fundamental dynamics of bubble-driven inertial micropumps using high-speed imaging, CFD simulations, and modeling to understand flow profiles, calibrate models, and analyze frequency-dependent efficiency.

Contribution

It combines experimental imaging with simulations and modeling to characterize single-pulse flow and frequency effects in inertial micropumps for the first time.

Findings

Confirmed N-shape flow profile during pump cycle

Calibrated models to determine effective bubble strength

Observed pump efficiency decrease with overlapping pulses

Abstract

Bubble-driven inertial pumps are a novel method of moving liquids through microchannels. We combine high-speed imaging, computational fluid dynamics (CFD) simulations and an effective one-dimensional model to study the fundamentals of inertial pumping. For the first time, single-pulse transient flow through U-shaped microchannels is imaged over the entire pump cycle with 4-microsecond temporal resolution. Observations confirm the fundamental N-shape flow profile predicted earlier by theory and simulations. Experimental flow rates are used to calibrate the CFD and one-dimensional models to extract an effective bubble strength. Then the frequency dependence of inertial pumping is studied both experimentally and numerically. The pump efficiency is found to gradually decrease once the successive pulses start to overlap in time.