Numerical simulation of the combustion of hydrogen–air mixture in micro-scaled chambers Part II: CFD analysis for a micro-combustor

Understanding of the flow dynamics, chemical kinetics and heat transfer mechanism within micro-combustors is essential for the development of combustion-based power MEMS devices. In Part I, CFD based numerical simulation has been proven to be an effective approach to analyse the performance of the micro-combustor under various conditions. In this paper, numerical simulations are performed to analyse the combustion behaviour in a three-dimensional micro-combustor based on the prototype used in the MIT micro-gas turbine engine. The CFD model of the micro-combustor includes fuel/air flow path, combustion chamber as well as solid walls used to construct the combustor. The simulation analysis includes not only the detailed chemical reactions occurred in the combustion chamber, but also the fluid flow dynamics, heat transfer within the combustor and heat loss to the ambient. The performance of the combustor is evaluated under various fuel/air ratio, flow rate and heat loss conditions. Through such systematic numerical analysis, a proper operation space for the micro-combustor is suggested, which may be used as the guideline for micro-combustor design. In addition, the results reported in this paper illustrate that the numerical simulation can be one of the most powerful and beneficial tools for the micro-combustor design, optimisation and performance analysis.