Study On Flow Field And Combustion Performance Of Dual-fuel Combustor In Aviation Gas Turbine

Gas turbines have developed rapidly in recent years.As the main component of gas turbines,the emission of pollutants from combustion chambers needs to be solved urgently.At present,aviation gas turbines use aviation kerosene as fuel,and pollution caused by combustion has become a major concern.Therefore,the development of low emission combustion technology and the search for new aviation alternative fuels have become a development direction.LNG has the characteristics of high calorific value,high combustion efficiency and low pollutant emission,and has been widely used in ground power equipment.In order to explore the feasibility of LNG as aviation fuel,this paper studies the combustion characteristics of an aviation kerosene/LNG dual fuel combustor.A low-emission dual fuel combustor with three-swirl central stages is studied in this paper.The combustion chamber model is established,and the flow field,temperature field and pollutant generation characteristics are analyzed by numerical simulation.The combustion performance of the dual fuel combustor with LNG as the main fuel and aviation kerosene as the duty fuel is studied by experimental test,and the established mathematical model is validated.Finally,the mathematical model established by the simulation simulates the combustion performance of the combustion chamber under three different fuel ratio schemes.Under the condition of determining the optimal fuel ratio,the influence of the change of air inlet temperature on the combustion characteristics of the dual fuel combustor is further explored.The results show that the designed dual fuel combustor is feasible in principle.The flow field in combustion chamber and the distribution of fuel flow accord with the operational requirements of aero-gas turbine.The experimental data analysis shows that the lean oil quenching characteristic of the combustor is good,and can be stably operated under different working conditions.With the increase of fuel flow rate in the main stage,the combustion efficiency increases and the pollutant emission decreases.When the ratio of duty fuel flow to main fuel flow is 1:3,the pollutant emission is lower,which meets the pollutant emission standard of aviation gas turbine.The numerical simulation analysis shows that with the increase of fuel flow rate in the main combustion stage,the main combustion zone of the combustor moves forward gradually,the area of the combustion zone increases,the total pressure recovery coefficient basically remains unchanged,the pollutant emission at the exit of the combustor decreases gradually,and the combustion efficiency increases gradually.When the air inlet temperature increases,the temperature of the main combustion zone in the combustor rises,which improves the atomization performance of fuel and the mixing degree of air and fuel.The combustion efficiency increases gradually,and the emission of CO and NO decreases gradually.However,with the increase of the air inlet temperature,the totalpressure recovery coefficient of the combustor decreases slightly,which has little effect on the stable combustion of the combustor.