Numerical Investigation Of Turbulent Nonpremixed Methane-air Flames

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Turbulent combustion is an important phenomenon in industrial applications, such as gas turbines, diesel engines, low NOx burners, spark-ignition engines and furnaces. Improvements are often necessary, since the applications have to be effective, economical and clean. Therefore, a better understanding of the turbulent combustion is needed. Numerical simulations, so-called Computational Fluid Dynamics (CFD), help to optimize and improve the applications in reacting flows. In comparison with experimental studies, CFD is relatively cheap. Although a complete simulation of a turbulent reacting flow, which involves all physical phenomena is not possible at present, the solutions of CFD is able to facilitate the device-scale analysis and the design of many new industrial combustion applications. The study of turbulent combustion is important from a scientific point of view as from a practical point of view. The use of the numerical models for industrial applications are first handled with a continuous cycle of 'the understanding of fundamentals of combustion', 'model developments', 'implementation of models in numerical simulations', and 'validation of the numerical results with experimental measurements'. When validating the numerical models, simple flame configurations are required. This fact brings the importance of studying the turbulent jet flows numerically and experimentally.Turbulent combustion research can be classified into two categories: non-premixed combustion and premixed combustion. In general, different modeling approaches are required to deal with each combustion category. New generation low emission/low fuel consumption combustion systems are characterized by a combined concept of two combustion categories, which is called partially premixed turbulent combustion. For example, lean premixed combustion systems for reducing NOx emissions in gas turbine combustors and gasoline direct injection spark-ignition engines fo