This project aims to fundamentally understand the governing physics behind inertial two-phase gas-liquid droplet microflows, with the objective of developing novel microfluidic systems capable of microsecond processing times and tens of mL/min throughputs, simultaneously. The transformative aspect of the project resides in providing new insights into the emerging field of high speed inertial microfluidics and droplet microflows in specific. This understanding will lead to the development of next generation Lab-on-a-Chip (LOC) and micro-Total Analysis Systems (mTAS) with processing speed and throughput capabilities not seen before.
The research aims to address (1) the role and interplay between inertial, viscous and surface tension forces in the droplet detachment mechanism, (2) mapping of the different flow regimes and transitions that can lead to droplet generation, and (3) the dynamics of inertial droplet collision mixing in a confined microchannel environment. Towards these goals, research efforts will be put forward that focus on the experimental study of the fast droplet dynamics and interactions through the use of novel optical diagnostics techniques. In specific, a microfluidic droplet generation platform that allows control and monitoring of the liquid and gas flows conditions will be coupled to a high speed microscopy system to study the liquid droplet entrainment dynamics. Similarly, a microfluidic droplet pair collision platform will be coupled to a high speed epi-fluorescence microscopy system, where differential dual fluorescence measurements and mPIV will be used as tools to unravel the fast dynamics associated with inertial collision mixing. The experimental work will be complemented by first order modeling and global force analysis of the different phenomena.
The intellectual merit of the project includes elucidating the role of inertial effects in the detachment, entrainment and collision mixing of liquid droplets in confined gas carrier microflows. The test structures and experiments to be carried out in this study will provide unique insight into the effects that different flow and boundary conditions have on droplet formation and collision coalescence. The microfluidic test samples to be used are designed and fabricated so that the geometry and flow conditions under which the droplets interact can be carefully controlled, allowing for a clearer understanding of the effects that different microscopic geometrical parameters have on the entrainment and collision coalescence processes.
The research endeavors and outcomes from this work will be integrated into educational and outreach activities that will introduce the field of microscale flow and transport to underrepresented undergraduate engineering and high school students early in their career. Innovative multilayer, self-sustainable programs geared towards development of teaching content while providing research training, will be introduced. Research training of individual students will take place through summer internship programs aimed at developing microfluidic and optical diagnostics lab modules and demonstrations. These will in turn be deployed and introduced in an undergraduate experimental class and several outreach programs, respectively.
