Applied Turbulent Combustion
Improved combustion devices that result from the use of predictive simulation-based design concepts enables industry to produce cleaner and more efficient turbine/reciprocating engines for power generation and vehicle transport. Substantial efficiency gains, of 20 to 50 percent, would dramatically enhance national energy security while simultaneously mitigating the effects of climate change. However, current predictive simulations offer limited accuracy due to lagging science-based numerical submodel development, which itself is hindered by a lack of high-fidelity measurements from well-characterized combustion experiments.
Within the Turbulent Combustion Laboratory (TCL), quantitative datasets are collected from a suite of characteristic turbulent flames types, and they form the basis for the creation of validated submodels that bridge fundamental energy sciences with applied device engineering and optimization.
Complementary burner facilities with identical gas handling, flow control, and data-acquisition capabilities have been built to separately examine the impact of convective transport and combustion chemistry on overall flame characteristics. Stereo-particle image velocimetry and laser Doppler velocimetry have been used to measure three-component turbulent flow velocities, while planar laser Rayleigh scatter and OH/CH planar laser induced fluorescence have been used to examine precombustion and ignition phenomena. Furthermore, combined spontaneous Raman spectroscopy, Rayleigh scatter, and OH/CO-laser-induced fluorescence measurements have been used to quantify in situ turbulent flame mixture fraction and scalar dissipation distributions. From all of these measurements, the fundamental drivers for flame kernel ignition and extinction have been illuminated, and the impact of turbulence/chemistry interactions have been explored.
Although the primary mission of the TCL is to investigate basic turbulent flame phenomena, more applied research activities have involved combined experimental/numerical efforts to examine synthetic and hydrogen enriched natural gas combustion within characteristic swirling turbine combustion chambers. Detailed fuel spatial distributions, combustion chamber flow measurements, and identified emission formation regions have served as benchmarks for large eddy simulation predictions performed by CRF numerical modelers. Due to the improved physical understanding of the thermochemical processes within the combustion chamber, new engineering models have been developed and existing models have been optimized.