SBIR Phase I: Multi-Environment Probability Density Function (PDF) Method for Modeling Turbulent Combustion Using Detailed Chemistry

This Small Business Innovation Research (SBIR) Phase I project will investigate the applicability and merit of applying the multi-environment probability density function (MEPDF) method to model turbulent combustion problems with realistic chemical kinetics within comprehensive CFD simulations of practical combustion equipment. MEPDF retains many of the desirable properties of the transported probability density function (PDF) method but at a fraction of the computational cost, including the ability to treat the chemical source term exactly and address the nonlinear interaction between turbulence and finite rate chemical reactions with great accuracy. MEPDF originated from multi-environment micro-mixing models used in the chemical engineering community to simulate chemical processes with little heat release. Recently this method has been extended to model gas phase combustion problems, but for only very simple chemistry. This project aims to further advance this method by extending it to incorporate realistic chemical kinetics for modeling combustion problems where turbulent-finite rate reaction interaction is crucial for accurate prediction such as pollutant emission (e.g., NOx, soot). The work would eventually extend the MEPDF method to model heterogeneous combustion problems, such as coal combustion, and provide means to simulate low NOx firing systems that are widely used in the power generation industry. The activities of extending the MEPDF method to simulate practical combustion systems using complex chemical kinetics would lead to a solid foundation of the scientific and engineering knowledge and understanding base. The value of an improved modeling tool to provide more reliable predictions of complex combustion processes is clearly evidenced by commercial concerns from various industries. The development of advanced tools from this project provides means for companies in the power generation, chemical process, mineral process, and incineration industries to improve product designs and services that would ultimately benefit the environment, global competitiveness, and national/homeland security. An improved understanding of pollutant formation and destruction processes, currently limited by the ability to accurately model these complex processes, will result in reductions of pollutant emissions. Reducing pollutant emissions from power plants, process furnaces, and incinerators will continue to be both a necessary environmental objective and a challenging engineering problem requiring the best investigational tools possible.