Ilker Yilmaz

An experimental study on premixed CNG/H2/CO2 mixture flames

Abstract In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.

Investigation of an Optimal Operating Condition for a Micro Combustor Regarding Basic Thermophotovoltaic System Requirements

In this study, effects of equivalence ratio and thermal power on combustion and emission behaviour of premixed hydrogen air mixtures were numerically investigated by constructing 3D micro combustor models. Combustion behaviour was analysed by examining combustor outer wall and centreline temperature profiles, and convective and radiative heat transfer quantities. Besides, emission behaviour was analysed in terms of centreline NOx profiles and NOx amounts emanated from exhaust of the micro combustor. Regarding these, optimal operating condition with respect to combustion performance and pollutant emissions was investigated by varying thermal power and equivalence ratio. Turbulence model used in this study is RNG k-e (Yilmaz et al. Int J Hydrog Energy 42:25744–25755, 2017). Multistep combustion reaction process with 9 species and 19 steps was simulated using Eddy dissipation concept model. Data obtained from this study was validated against published experimental data (Tang et al. Int J Hydrog Energy 40:2396–2403, 2015). Results showed that optimal operating condition can be gained at 0.8 equivalence ratio and 1200 ml/min hydrogen flux.