Modeling of Turbulent Nonpremixed Combustion

Abstract

As for industrial combustion apparatuses, turbulent nonpremixed combustion systems are widely used due to the facility for stabilization; i.e., the safety. However, the systems produce easily unexpected gases such as NOx and soot. The information in advance based on numerical simulation is crucial for the design of combustion apparatus to optimize the system. In the present review paper, regimes of nonpremixed combustion are given and the modeling is explained. The eddy dissipation model is empirical or intuitive, but robust. The flamelet model is widely used in industrial and academic levels, but in controversy for assumptions. The conditional moment closure method is an improvement of the flamelet model. The PDF method can deal with reaction exactly, but costly. The presumed multivariate PDF method may be a solution of the turbulent combustion modeling. This method is between the flamelet model and the PDF method, with the ability of exact evaluation of reaction.