Effect of oxygen enrichment on the combustion characteristic and pollutant emissions of kerosene-biogas mixtures on a mini jet engine combustion chamber

Abstract

There are many alternative fuel studies in gas turbine engines, which are widely used in aviation and energy production. Biogas has also become popular among alternative fuels, especially since it can be obtained from waste. Biogas not only provides a renewable energy source, but also helps to manage organic waste, reduce greenhouse gas emissions and promote sustainable practices in waste management and energy production. The most important issue for alternative fuel studies in gas turbine engines is maximum emission reduction with minimum efficiency loss. In this study, oxygen enrichment and alternative fuel simulation were performed on a mini gas turbine engine. The biogas/kerosene mixture was used together with the oxygen enrichment method, which is known to increase the flame temperature in the literature, due to the lowering effect of the biogas on the combustion chamber outlet temperature.As an alternative fuel, biogas was mixed with kerosene up to 50% in 10% increments. The geometry of the GTM-120 engine used in the study was simplified and validated with the combustion chamber outlet temperatures at 3 different rpms created with the fuel and air inlet conditions taken from the literature. While kerosene fuel is injected from 12 nozzles with Discrete Phase Method, k-e turbulence model and Discrete Ordinates radiation model are used. Alternative fuel was given from the nozzle surfaces as a mass flow inlet by calculating the flow rate so that the thermal power remains constant. All simulations were made with steady-state and 1600 iterations. As a result, it was observed that oxygen enrichment increased the flame temperature and NOX formation, while decreasing the CO emission.On the other hand, it has been observed that the CO2 in the biogas reduces both the temperature and NOX emissions due to its diluting effect, while at the same time increasing the CO emissions in the front region. Furthermore, the decrease in the total C/H mass also led to a reduction in the CO emission at the outlet. Another effect of the biogas was the reduction in the CO2 at the outlet. Thanks to this study, the use of alternative fuels and a decrease in pollutant emissions have been achieved by keeping the loss of engine efficiency at a minimum.With this study, it has been demonstrated that biogas can be used as an alternative fuel with kerosene by keeping the engine efficiency loss to a minimum and a decrease in pollutant emissions.