Analysis On Biofuel Combustion Characteristics Of DGEN380 Engine

In recent years,with the development of Chinese economy and the improvement of people's living standards,air-transport industry of China has developed rapidly.The demand for traditional aviation fuels,especially aviation kerosene,have gradually increased,resulting in a sharp increase in aviation carbon emissions.In addition,with the awareness of environmental protection and the attention to the greenhouse effect increasing,the air-transport industry faces enormous pressures to reduce emissions of CO2.The carbon emissions of biofuels are reduced by 50%compared with aviation kerosene.It is of great significance to study the application of biofuels in aero-engines.The purpose of this paper is to study the combustion characteristics of biofuels on aero-engines by numerical simulation,mainly to study the lean blowout characteristics of biofuels,and to study the feasibility of replacing aviation kerosene with biofuels in the future.Furthermore,by modifying the model of the combustion chamber,the effect of the swirl cup sleeve outlet form on the combustion performance of the biofuel is investigated.This paper takes the DGEN380 engine as the research object.Bioethanol and biodiesel are selected as the representatives of biofuels.Firstly,the size data of the combustion chamber is obtained by Geomagic Studio and reverse modeling is carried out in UG.The numerical simulation is carried out with Fluent and the simulated values are compared with the experimental values to verify the correctness of the combustion chamber model.Then,the steady combustion process is simulated.The fuel steady state successive approximation method and the characteristic node method are used to predict the lean blowout limit of aviation kerosene,and the lean blowout limit of aviation kerosene is compared with that of biodiesel and bioethanol.Finally,by changing the combustion chamber model,mainly changing the form of the swirl cup sleeve outlet,the influence of the swirl cup sleeve outlet form on the combustion characteristics of biofuels is studied.The research content of this paper can provide theoretical support for the large-scale use of biofuels in the civil aviation field.The simulation results show that the lean blowout limit of aviation kerosene is 0.0052,and the lean blowout limit of biodiesel and bioethanol are 0.0066 and 0.0083,which is 26.9%and 59.6%higher than that of aviation kerosene respectively.Biodiesel meets the existing regulations for the lean blowout limit of civil aviation engines,which is less than 0.007.The effects of different expansion angles on the temperature distribution and the shape of the recirculation zone are studied and the optimum expansion angle of the combustion chamber is selected as 80~?.The lean blowout limit of biodiesel at the expansion sleeve outlet is 3%lower than that of the smooth sleeve outlet.The expansion sleeve outlet is more suitable for biodiesel.