| Combustor is a critical part of aero-engine,and its capability have an important influence on the performance of the aircraft.Combustor in active service can not meet requirements of high combustion efficiency,low total pressure loss,low pollutants emissions and uniform temperature distribution at exit of the aero-engine simultaneously,so it is of great significance to improve the engine performance by enhancing and proposing new combustor.A three-duct annual advanced vortex combustor(AVC)and it's improvements was proposed and studied in this paper by numerical simulation and theoretical analysis,meanwhile the performance of a three-dimensional annular AVC with vane was also explored.First of all,a three-duct annul AVC was proposed in this paper.Numerical simulations of different duct parameters,ratios of different heights of rear bluff and the front bluff body(H2/H1),ratios of different cavity width and the front bluff body(L/H1)were conducted.The results show the dual-vortex pair can be achieved in the range of L/H1=0.4~0.5 when H2/H1=0.4~0.7 and L/H1=0.6~0.7 when H2/H1=0.4~0.5in the AVC.The H2/H1 parameter makes total pressure loss coefficient and combustion efficiency of the AVC decrease firstly,and then increase,with no influence in the L/H1 and the duct parameters.A raising combustion efficiency of 11.59% is obtained with total pressure loss coefficient increased by only 0.12% by comparisons of the three-duct AVC developing dual-vortex pairs with the dual-duct AVC.Secondly,to enhance mixing ration between mainstream and heat source in the cavity and to improve the performance of the three-duct AVC for technological reserve to engineering applications,a three-duct combustor equipped with wedge flame stabilizer was proposed and the effect of the wedge parameters on the performance of the proposed combustor was numerically simulated.The results show the wedge can increase combustion efficiency significantly,reduce emission NO and contribute to better temperature distribution at the exit of the AVC,with little increment on total pressure loss coefficient.The best overall performance was achieved when ? = 80o,D/S = 3.5%,L/H1 = 1 ~ 2(where ? is defined as angle of wedge,D is the width of wedge,S is the length of combustor,L is the distance between the wedge and blunt body,and H1 the height of the blunt body)Thirdly,for a 3-D annular AVC with guide vane,the influence of the structural parameters of the guide vane on the performance of the AVC was conducted in this paper.A dual-vortex pair is formed in the cavity and the largest one is in the middle section in the AVC,the dual-vortex pair becomes smaller,when the cross section closer to the side section in the AVC,and it becomes single vortex pair when the cross section is on the sides of rear blunt body.The best overall performance was achieved when c/H1 = 0.2,e/B = 0.2 and b/L=0.1.The effect of velocity,temperature and equivalent ratio of mainstream of air and fuel on the performance of the AVC was studied based on the obtained structural parameters of the guide vane.The results show that the position of the vortex core keeps almost unchanged with increasing on the equivalent ratio of mainstream of air and fuel,but the inner vortex pair becomes smaller,the combustion efficiency is reduced and the total pressure loss coefficient is increased.The raising of inlet temperature is benefit to the vortex stable,reducing total pressure loss coefficient and raising combustion efficiency.But the increasing of inlet temperature and equivalent ratio of mainstream of air and fuel both makes the combustion temperature and emission NO higher.The mainstream velocity demonstrates less effect on the performance of the AVC compared with the inlet temperature and the equivalent ratio of mainstream of air and fuel.Finally,summarizations and conclusions were conducted in the paper,and the direction of further research was indicated. |
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