Study On The Combustion And Emission Performance Of A Novel Integrated Staged Combustor

In order to simultaneously achieve high combustion efficiency,low pollution emissions,ideal outlet temperature distribution and good flame stability of aero-engine combustor,this thesis proposes an integrated staged combustion technology that combines the advantages of trapped-vortex combustion technology and swirling combustion technology,and designs a novel integrated staged combustor.The pilot of novel integrated staged combustor adopts two independent cavities to achieve stable combustion,and the main（mainstream）uses a swirler to obtain quick mixing between the cavity’s hot products and the mainstream fuel/air mixture.For the novel integrated staged combustor,the effects of two different cavity-air modes（case-1 and case-2）on the combustion efficiency,pollutant emissions,outlet temperature distribution,flame stability and flow characteristics were studied under the conditions of inlet temperature of 373 K and 473 K,and pressure of one standard atmospheric pressure by combining experimental research and numerical simulation.The experimental research results are as follows:1)It is found that the combustion and emission performance of the novel integrated staged combustor is influenced by the cavity-air modes.2)The atomization characteristics of fuel will also have a certain impact on the combustion and emission performance of the novel integrated staged combustor.3)When fuel is only supplied to the cavity:Under the most operating conditions,the combustion efficiency of case-2 is higher than that of case-1.The EI_COof case-1 is higher than that of case-2.WhenΔP=2.5%andΔP=3.0%,the EI_NOxof case-2 is always higher than that of case-1.WhenΔP=3.5%,the EI_NOxof case-1 is higher than that of case-2.The outlet temperature distribution of case-2 is more uniform than that of case-1.4)When fuel is simultaneously supplied to the cavity and mainstream:Under the most operating conditions,the combustion efficiency of case-2 is higher than that of case-1,and the combustion efficiency is always above 99%.The EI_COof case-2 is lower than that of case-1.The EI_NOxof case-2 is lower than that of case-1.The outlet temperature distribution of P0 plane corresponding to case-1 is more uniform than that of the P0 plane corresponding to case-2,and the outlet temperature distribution of the P1 plane corresponding to case-2 is more uniform than that of the P1 plane corresponding to case-1.In addition,the numerical simulation results are as follows:1)Two stable vortexes,which are formed inside the cavities of case-1 and case-2,are not affected by the mainstream jet,so the good flame stability of the novel integrated staged combustor is achieved.2)Under the action of the swirler,a stable mainstream vortex is formed downstream of the swirler,fast and uniform mixing between the cavity’s hot products and the mainstream fuel/air and excellent combustion and emission performance are achieved in the novel integrated staged combustor.3)The turbulence intensity inside the cavity of case-2 is higher than that inside the cavity of case-1,which proves that the flame stability of case-1 is higher than that of case-2.Moreover,whether it is only supplied fuel to the cavity or both cavity and mainstream,the combustion efficiency of case-2 is higher than that of case-1.Therefore,the simulation results based on the Reynolds averaged Navier Stokes（RANS）equation indicate that the main reason for the differences between combustion and emission performance of the novel staged combustor is the differences in flow characteristics caused by two different cavity-air modes.The novel staged combustor proposed in this thesis provides a certain reference value for the design of advanced aviation engine combustor,especially for combustor designs that achieve excellent combustion and emission performance based on different cavity-air modes.