Research On Combustion Characteristics Of Lean Direct Injection Combustor

With the increasing environmental pollution and people’s awareness of environmental protection,the problem of engine emissions has been widely concerned by the society.In order to develop low emission combustion technology to reduce the emission of aircraft combustor,the numerical simulations and experimental investigation about lean direct injection(LDI)combustor was conducted in this paper.Two different kinds of axial swirlers were devised to study the influence of swirler vane angle on characteristics of LDI combustor,such as the flow characters,combustion characters,emission,ignite and blow out characters.Except that,the research subjects also include two different swirler array modes and three different swirler distances of 4-point combustors.(1)The simulations of single-point LDI combustors with different swirler vane angle show that: the swirler of 60°vane angle can form reverse flow area,while the swirler of 45°vane angle can’t.Under the same conditions,the combustor total pressure loss of the 60°vane angle swirler is higher than the 45°vane angle swirler 5%.The temperature and NO emission of combutor with 60°vane angle swirler are higer than the combutor with 45°vane angle swirler.(2)The researches of vane angle of 4-point LDI combustors show that: Under the same conditions,the combustor total pressure loss of the 60°vane angle swirler is higher than the 45°vane angle swirler.The temperature of combutor with 45° vane angle swirler are higer,while the NO emission is lower,which means the 45° vane angle swirler is conducive to improving the combustion efficiency and making the temperature distribution more uniform.(3)The researches of array modes of 4-point LDI combustors show that: the center area of 4 swirler of Case1 array forming a new rotational core,while the Case2 array can’t.The temperature of Case1 array of 45°vane angle swirler are higher than Case2 array,while the emission of this two array modes at lean are similar,which meas the Case1 array is better than Case2 array.As for the combustor of 60°vane angle swirler,the Case2 array is better.(4)The researches of center distances of 4-point LDI combustors show that: With the decrease of center distances of adjacent swirlers,the interaction of adjacent fluid is stronger.At the combustor with 45°vane angle swirlers,the temperature of the model of dc=35.23 mm is highest,the temperature of the model of dc=29.82 mm is lowest.At the combustor with 60°vane angle swirlers,with the increase of the distance,the temperature of combustor is lower.Taking the combustion efficiency and the emission into account,dc=40.64 mm is best for the combustor with 45°vane angle swirlers while dc=35.23 mm is best for the combustor with 60°vane angle swirlers.(5)The experimental results validate the theoretical simulation very well.The variations of the total pressure loss and effective area with the inlet flow are resulted.The ignite equivalence ratios and the blow out equivalence ratios of the 60°vane angle swirler combustors are higher than the 45°vane angle swirler combustors.