Abstract:
The speaker has been conducting research that is sponsored by General Electric and by the U.S. Department of Energy to understand how to minimize nitric oxide using new Lean Premixed Prevaporized (LPP) technology. Another study involves syngas (hydrogen and carbon monoxide). In both cases, realistic swirl burners are used that produce very low levels of nitric oxide, but further improvements are limited by undesirable combustion dynamics, including acoustic instabilities. A challenge is to understand these combustion dynamics to find ways to avoid them to operate at ultra-lean conditions.
Kilohertz PLIF and PIV laser imaging methods were used to take high-speed movies of the flames and the velocity fields (at 4,000 images/second) to measure the turbulent mixing within an ultra-lean gas-turbine like combustor with different fuels. Low nitric oxides are achieved and the boundaries are measured where the combustion instabilities begin. Another challenge is to develop a CFD model of the unsteady dynamics. A reduced-order model was developed that contains two ordinary differential equation; it adequately explains the trends associated with the combustion instability (frequency, intensity, phase angles). The simple model is a useful tool to help develop more accurate CFD simulations of combustion dynamics in the future.

Driscoll abreviated resume 2015-short.pdf