椭圆形超燃燃烧室内燃料喷射和掺混性能研究
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摘要
为了优化超燃燃烧室的工作效率和性能,针对椭圆形超燃燃烧室内的燃料壁面垂直喷射方案,通过求解雷诺平均Navier-Stokes方程的数值模拟方法对不同燃料喷射方案进行研究,着重分析了不同喷注位置的壁面曲率值、喷嘴直径以及反射激波干扰对流场特征及燃料掺混特性的影响。研究表明,喷注位置的壁面曲率对燃料掺混的影响程度与喷嘴直径相关。当喷嘴直径较大时,壁面曲率值越小,燃料的掺混效率越高,但总压恢复系数越低;当喷嘴直径较小时,壁面曲率的改变对燃料横向喷流方案的掺混效率和总压恢复影响很小。在相同喷射动压比下,不同喷嘴直径方案的流场特征以及燃料喷射掺混特性均存在相似性,缩小喷嘴直径能够提高燃料的掺混效率。就本文的研究状态,喷嘴直径为4mm的方案在燃烧室出口处的掺混效率比直径为10mm方案的高出约46.7%。此外,通道中的激波/掺混层相互干扰会大幅降低燃料穿透深度,但产生的剧烈剪切运动能够提高燃料掺混效率。
In order to optimize operating efficiency for a scramjet combustor, different injection cases in an elliptical scramjet combustor were numerically investigated by using Reynolds-Averaged Navier-Stokes(RANS),and effects of wall curvature of different injection positions,injector diameters and reflected shock interaction on injection and mixing performance of transverse jet were analyzed.Results show that effects of wall curvature of injection positions on mixing performance are highly related to injector diameters.For the case with larger injector diameter,decreasing the wall curvature enhances mixing efficiency of the fuel,but damps out the total pressure recovery.However,for the smaller diameter case,variation of wall curvature rarely affects the mixing performance and total pressure recovery.At the same momentum ratio condition,similarities of different diameter cases are found regarding the flow characteristics,injection and mixing performance of different diameter cases.To reduce the injector diameter can effectively improve mixing efficiency of the fuel.For the cases studied in this paper,the mixing efficiency at the combustor outlet of 4mm injector diameter case is higher than that of 10 mm case by 46.7%.Additionally,interaction between reflected shock and mixing layer in the combustor substantially reduces penetration height of the jet,but enhances mixing efficiency due to the intense shearing motion induced by the interaction.
In order to optimize operating efficiency for a scramjet combustor, different injection cases in an elliptical scramjet combustor were numerically investigated by using Reynolds-Averaged Navier-Stokes(RANS),and effects of wall curvature of different injection positions,injector diameters and reflected shock interaction on injection and mixing performance of transverse jet were analyzed.Results show that effects of wall curvature of injection positions on mixing performance are highly related to injector diameters.For the case with larger injector diameter,decreasing the wall curvature enhances mixing efficiency of the fuel,but damps out the total pressure recovery.However,for the smaller diameter case,variation of wall curvature rarely affects the mixing performance and total pressure recovery.At the same momentum ratio condition,similarities of different diameter cases are found regarding the flow characteristics,injection and mixing performance of different diameter cases.To reduce the injector diameter can effectively improve mixing efficiency of the fuel.For the cases studied in this paper,the mixing efficiency at the combustor outlet of 4mm injector diameter case is higher than that of 10 mm case by 46.7%.Additionally,interaction between reflected shock and mixing layer in the combustor substantially reduces penetration height of the jet,but enhances mixing efficiency due to the intense shearing motion induced by the interaction.
引文
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[21]Fuller R,Wu P K,Nejad A,et al.Fuel-Vortex Interactions for Enhanced Mixing in Supersonic Flow[C].Lake Buena Vista:32nd Joint Propulsion Conference and Exhibit,1996.
[22]Mcclinton C R.Effect of Ratio of Wall Boundary Layer Thickness to Jet Diameter on Mixing of a Normal Hydrogen Jet in a Supersonic Stream[R].NASA-TM-X-3030.
[2]Mai T,Sakimitsu Y,Nakamura H,et al.Effect of the Incident Shock Wave Interacting with Transversal Jet Flow on the Mixing and Combustion[J].Proceedings of the Combustion Institute,2011,33(2):2335-2342.
[3]Shekarian A A,Tabejamaat S,Shoraka Y.Effects of Incident Shock Wave on Mixing and Flame Holding of Hydrogen in Supersonic Air Flow[J].International Journal of Hydrogen Energy,2014,39(19):10284-10292.
[4]You Y,Luedeke H,Hannemann K.Injection and Mixing in a Scramjet Combustor:DES and RANS Studies[J].Proceedings of the Combustion Institute,2013,34(2):2083-2092.
[5]Huang W,Liu J,Jin L,et al.Molecular Weight and In-jector Configuration Effects on the Transverse Injection Flow Field Properties in Supersonic Flows[J].Aerospace Science and Technology,2014,32(1):94-102.
[6]Wei H.Design Exploration of Three-Dimensional Transverse Jet in a Supersonic Crossflow Based on Data Mining and Multi-Objective Design Optimization Approaches[J].International Journal of Hydrogen Energy,2014,39(8):3914-3925.
[7]高振勋,李椿萱.几种超声速横向射流方案混合特性的数值研究[J].中国科学:技术科学,2011,41(7):1010-1020.
[8]孙得川,蔡体敏.超声速流动中横向射流流场的影响参数[J].推进技术,2001,22(2):147-150.(SUN De-chuan,CAI Ti-min.Effecting Parameters of Supersonic Flowfield with Secondary Injection[J].Journal of Propulsion Technology,2001,22(2):147-150.)
[9]贾真,朴英,吴迪.浅凹槽底壁横向燃料喷射对流动和燃烧特性的影响[J].推进技术,2013,34(1):81-87.(JIA Zhen,PIAO Ying,WU Di.Effects of Transverse Injection from Bottom Wall of Shallow Cavity on Flow and Combustion Characteristics of Supersonic Combustor[J].Journal of Propulsion Technology,2013,34(1):81-87.)
[10]Smart M,Ruf E.Free-Jet Testing of a REST Scramjet at Off-Design Conditions[R].AIAA 2006-2955.
[11]黄伟,王振国,罗世彬,等.高超声速乘波体飞行器机身/发动机一体化关键技术研究[J].固体火箭技术,2009,32(3):242-248.
[12]黄伟,罗世彬,王振国.临近空间高超声速飞行器关键技术及展望[J].宇航学报,2010,31(5):1259-1265.
[13]Gruber M R,Nejadt A S,Chen T H,et al.Mixing and Penetration Studies of Sonic Jets in a Mach 2 Freestream[J].Journal of Propulsion and Power,2012,11(2):315-323.
[14]Yasuhiro W,LIOU M.A Flux Splitting Scheme with High-Resolution and Robustness for Discontinuities[R].AIAA 94-0083.
[15]Menter F R.Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications[J].AIAA Journal,2012,32(8):1598-1605.
[16]Aso S,Okuyama S,Kawai M,et al.Experimental Study on Mixing Phenomena in Supersonic Flows with Slot Injection[R].AIAA 91-0016.
[17]谭大刚,唐功建,宋冈霖,等.气动斜坡/燃气发生器方案燃料掺混性能研究[J].航空发动机,2015,41(1):41-47.
[18]Doster J C,King P I,Gruber M R,et al.In-Stream Hypermixer Fueling Pylons in Supersonic Flow[J].Journal of Propulsion and Power,2009,25(4):885-901.
[19]Viti V,Neel R,Schetz J A.Detailed Flow Physics of the Supersonic Jet Interaction Flow Field[J].Physics of Fluids,2009,21(4).
[20]YOU Y,Lüdeke H,Hannemann K.On the Flow Physics of a Low Momentum Flux Ratio Jet in a Supersonic Turbulent Crossflow[J].Europhysics Letters,2012,97(2):24001-24006.
[21]Fuller R,Wu P K,Nejad A,et al.Fuel-Vortex Interactions for Enhanced Mixing in Supersonic Flow[C].Lake Buena Vista:32nd Joint Propulsion Conference and Exhibit,1996.
[22]Mcclinton C R.Effect of Ratio of Wall Boundary Layer Thickness to Jet Diameter on Mixing of a Normal Hydrogen Jet in a Supersonic Stream[R].NASA-TM-X-3030.