Micro-combustor is a major component in which thechemical energy of hydrocarbon is converted to thermal energy via combustion. Themajor challenge in micro combustor is maintaining stable combustion. Most micro-combustorsoperate with heterogeneous (catalytic) combustion rather than with pure gaseouscombustion.
This is mainly because of large surface-to-volume ratios of micro combustorsthat result in improved stability compared to those of pure gaseous combustion.Conducting experiments in combustion characteristics in micro-scale devices aredifficult because measuring instrument causes disturbance to the microflame. Therefore,computational fluid dynamics (CFD) simulation is applied to investigate themicro-combustion mechanism. The development of multidimensional CFD models isessential for the advancement of catalytically stabilized combustion (CST) tocommercial systems.
In power generation there is increased interest forhydrogen-assisted CST. Hydrogen and hydrogen-based fuels are gaining rapidattention in recent years due to high energy densities compared to that ofbatteries. Addition of small amounts of H2 in natural gas can reducethe catalyst light-off temperature and can improve stability by dampingcombustion-induced pulsations.
In the present work, Computational Fluid Dynamics (CFD)based numerical simulations will be performed to study the combustion of hydrogenassisted catalytic ignition of lean methane/air mixtures on platinum. The flamestructure and wall flame interactions will be studied extensively. Mainobjective of this study is to evaluate flame stability of this micro-combustorthrough numerical experiments. Thermal performance of the micro-combustor willbe analysed for variable inlet mass flow rates and different wall thermalconductivities. The effects of micro-combustor dimension, thickness of wall andcombustion characteristics will be studied. Computational fluid dynamics codeFLUENT will be used to perform numerical simulations by solving theconservation equations of energy, mass and momentum.
The results of the numericalsimulations will then be compared to that of experimental results. Results ofthis study will tell whether hydrogen assisted catalytic ignition of leanmethane/air mixtures is a viable choice for fuelling the micro-combustor.