افشين سعيدي اسبوئي

In the present study, the effect of using gaseous hydrogen in combination with a liquid hydrocarbon fuel on turbulence–chemistry interaction an‎d the behavior of turbulent reactive flow in a model aero gas turbine combustor is investigated. The multiphase flow was simulated using an Eulerian-Lagrangian approach, an‎d turbulence was modeled with the Realizable k–ε formulation. For combustion modeling, both the Flamelet an‎d chemical equilibrium models were employed in this study. Validation of the numerical results is performed using experimental data, including velocity, temperature, an‎d NOx concentration profiles. The modeling of NOx emissions is carried out in a post-processing framework. Since the method of hydrogen addition to the liquid fuel has a direct impact on the physical an‎d thermodynamic properties as well as on turbulence–chemistry interaction, two distinct scenarios are defined an‎d investigated. In the first scenario (Energy-Balanced), in order to maintain a constant released energy, a portion of the liquid fuel mass flow rate is reduced. Accordingly, for 20%, 40%, an‎d 60% replacement of the hydrocarbon liquid fuel mass flow rate, hydrogen is injected at mass flow rates of 0.00002, 0.00004, an‎d 0.00006 kg/s, respectively. In the second scenario (Energy-Added), the liquid fuel mass flow rate is kept constant, an‎d identical amounts of hydrogen are injected into the system. The results indicate that the hydrogen injection strategy has a significant impact on the flow structure, mixing characteristics, temperature field, an‎d pollutant formation. In the first scenario, the reduction in the total fuel flow rate an‎d the shift toward lean combustion lead to a decrease in temperature; however, no significant reduction in NOx emissions is observed. In contrast, in the second scenario, the increase in thermal power an‎d the intensification of turbulence–chemistry interaction result in stronger an‎d displaced hot spots, accompanied by higher NOx production. The turbine inlet temperature decreases from 1062 K to approximately 1010 K in the first scenario, whereas in the second scenario it increases to 1418 K. The mean CO₂ mass fraction at the combustor outlet decreases from 0.099 to 0.042 in the first scenario, whereas in the second scenario it increases from 0.099 to 0.102. An examination of the radial distribution of the CO₂ mass fraction indicates that, in the first scenario, the reduction in carbon input an‎d the dilution of combustion products are the primary contributing factors. In contrast, in the second scenario, the temperature field an‎d mixing intensity play a more dominant role in governing variations in the carbon dioxide mass fraction. The selec‎tion of the hydrogen addition strategy is therefore a determining factor in controlling the thermal behavior an‎d combustion products of gas turbine combustors, an‎d it provides an effective framework for the development of gas turbine systems fueled with hydrogen-enriched fuels

محفظه احتراق مدل توربين گاز , سوخت مايع هيدروكربني , هيدروژن , برهم‌كنش آشفتگي- شيمي

Model gas turbine combustor , liquid hydrocarbon fuel , hydrogen , turbulence–chemistry interaction

Afshin Saeedi Esbooei

Dr.Farzad Bazdidi Tehrani