In this area of research, we study the combustion dynamics of an isolated droplet surrounded by a near-spherical flame, which is the canonical combustion configuration for liquid fuels. The spherical symmetry is experimentally achieved by burning fuel droplets in an environment with reduced Reynolds and Rayleigh numbers. Techniques used for this purpose include burning small fuel droplets, dropping the experimental package in a drop tower, or conducting experiments onboard the International Space Station. Liquid fuels of interest include practical transportation fuels (gasoline, diesel, and jet fuel), surrogate fuels, and bio-derived fuels (e.g., butanol and algae-derived biofuels). The current work in this area focuses on building a high-pressure combustion apparatus to study the burning characteristics of hydrocarbons and biofuels at elevated pressures representative of practical engines.

In this area, we work on a nonintrusive and cost-effective method to obtain quantitative soot volume fraction measurements that provide spatial and temporal resolution of sooting dynamics for liquid fuel combustion. A full-field light extinction technique is being developed for this purpose. It is based on the attenuation of light when a single-wavelength light beam passes through the soot-containing region of the flame. This technique can be incorporated into various combustion systems. Experimental results from this technique will be extremely useful in evaluating the soot emissions during the combustion of biofuels and providing data for model validation.

This research area focuses on fabricating mechanical devices at the micro-/nano-scale and exploring their applications in energy and biomedical research. Projects in this area include the following: (1) developing a novel method based on Leidenfrost levitation and exploring its potential as a biomass reactor and (2) developing microfluidic biosensors for the detection of pathogens.