Using the Conditional Moment Closure Method to Assess the Effects of Turbulence Chemical Kinetics

The ability to accurately design and predict the performance of combustion-based machinery like gas turbine engines is important in improving their performance, increasing their fuel economy, lowering operating costs, and decreasing pollutant emissions. Almost all of the flows are turbulent in industrial combustion applications, therefore understanding the interaction between turbulence and combustion chemistry is also important. Currently most reacting flow CFD codes employ subgrid combustion models tuned with the reaction kinetics measured in laminar flows. As a result, it is possible that we are not accounting for the chemistry-turbulence interaction correctly, ultimately resulting in sub-optimized combustion system hardware designs. We are therefore proposing to investigate this interaction on a simple, small-scale level as a means to identify and quantify kinetic reaction path differences between the laminar and turbulent flame regimes. Success in this effort will allow us to extract new reduced kinetic mechanisms applicable to both regimes and improve the solution quality of reacting flow CFD codes. We also expect this effort will improve our ability to economically extract reduced mechanisms with lower overall computational costs, materially improving the productivity of reacting flow CFD simulations.