Abstract

Non-premixed combustion process is an important subject in most applications of combustion. Understanding of this phenomenon is crucial in the design of reliable, efficient, economical power generation systems. Microfabrication technologies in the development of power micro electro-mechanical systems is also becoming an increasing trend nowadays and the complete understanding of microfluid dynamics and non-premixed micro-combustion phenomena will lead the success in this field. In recent years numerical simulations have become an essential tool to understand combustion process to overcome experimental problems without losing accuracy. In this study, two numerical simulations were performed on the analysis of the effect of injection on the turbulent mixing quality in a simple combustor and on the dynamics non-premixed flame street in a mesoscale channel using the commercial software Fluent®. The effect of inlet geometries were first investigated for a Lockwood-type combustor in terms of combustion and energy efficiency and an efficient design configuration is deduced. The effect of wall temperature and flow velocities on the dynamics of non-premixed flame in a scaled combustion channel was investigated in the second part of this study. The results suggest that the two main parameters affecting the development of a non-premixed flame street in a mesoscale channel are the heat transfer to and from the wall and the diffusion time of the flow. The analysis of numerical details such as grid resolution, turbulent and chemistry models is emphasized throughout the study to understand the influence of these numerical parameters on the simulated phenomenon by comparing with experimental observations.