Effects of turning mixing duct on lobed mixer performance
-
摘要: 针对波瓣混合器进行了一系列的数值计算和模型实验研究,揭示了带拐弯混合管对波瓣混合器性能的影响.实验结果表明:混合管长径比小于2时,带拐弯混合管会造成高温气流在出口截面呈月牙形分布,月牙形包围着一个回流区,该回流现象对引射性能不利,计算结果则验证了该气流分布,认为带拐弯混合管降低了波瓣混合器的引射效率,为改善其引射性能,应该加长混合管使得混合管的长径比大于等于2.计算结果还发现了波瓣混合器的最佳长径比为2,且该值不随面积比变化,和最佳长径比为6的圆管混合器相比,波瓣混合器可以有效缩短混合管的长度.另外,进一步给出了引射比与长径比的拟合关系式.Abstract: Based on a series of numerical computations and model experiments on the lobed mixer, the effects of turning mixing duct on the lobed mixer performance were revealed. The experimental results show that a crescent-shaped high temperature flow area is formed at the outlet cross section caused by turning mixing duct if the length-diameter ratio of mixing duct is less than 2. And a backflow zone is also found in the center of this area which is disadvantageous to the pumping performance. However, the numerical results not only verify the air flow distribution, but also show that the turning mixing duct lower the pumping efficiency of lobed mixer, and the mixer duct length should be increased for better pumping performance. To achieve a satisfied lobed mixer performance, the length-diameter ratio should not be less than 2. The numerical results also show that the optimum length-diameter ratio of lobed mixer is 2, which may not vary with the area ratio. Compared with pipe mixer whose optimum length-diameter ratio is 6, the lobed mixer could shorten the mixing duct effectively. Furthermore, fitting relations between the pumping ratio and length-diameter ratio are also presented.
-
Key words:
- lobed mixer /
- turning mixing duct /
- pumping ratio /
- optimum length-diameter ratio /
- area ratio
-
[1] Crouch R W, Coughlin C L, Paynter G C.Nozzle exit flow profile shaping for jet noise reduction[J].Journal of Aircraft, 1977, 14(9):860-867. [2] Presz W M.Thrust augmentation with mixer/ejector systems[R].AIAA 94-0200, 1994. [3] Power G D, McClure M D, Vinh D.Advanced IR suppress or design using a combined CFD/test approach[R].AIAA 94-3215, 1994. [4] 张靖周, 单勇, 李立国.直升机排气系统用波瓣喷管混合器引射-混合式红外抑制器研究[J].航空学报, 2007, 28(1):32-36. ZHANG Jingzhou, SHAN Yong, LI Liguo.Investigation on lobed nozzle mixer-ejector infrared suppressor for helicopter exhaust system[J].Acta Aeronautica et Astronautica Sinica, 2007, 28(1):32-36.(in Chinese) [5] Presz W M.Mixer/ejector noise suppressors[R].AIAA 91-2243, 1991. [6] Presz W M, Gousy R G, Morin B L.Forced mixer lobes in ejector designs[R].AIAA 86-1614, 1986. [7] Skebe S A, Paterson R W, Barber T J.Experimenta1 investigation of three-dimensional forced mixer lobe flow fields[R].AIAA 88-3785, 1988. [8] Belovich V M, Samimy M.Mixing process in a coaxial geometry with a central lobed mixer-nozzle[R].AIAA 96-0118, 1996. [9] Presz W M, Werle M.Multi-stage mixer/ejector systems[R].AIAA-2002-4064, 2002. [10] Cooper N J, Merati P.Numerical simulation of the vortical structures in a lobed jet mixing flow[R].AIAA-2005-635, 2005. [11] Presz W M, Morin B L, Blinn R F.Short efficient ejector systems[R].AIAA 87-1837, 1987. [12] Yu S C M, Xu G X.Turbulent mixing of coaxial nozzle flows with a central-lobed mixer[J].Journal of Propulsion and Power, 1997, 13(4):517-523. [13] Mickelsen J, Yarrington C, Bons J, et al.The effect of core flow turbulence on planar lobed-mixer nozzle effectiveness[R].AIAA-2006-18, 2006. [14] 路玉霞, 吴寿生, 黄勇.红外抑制器地面模拟试验研究[R].江西 景德镇:602所科研报告, KT-01-13, 2002. [15] 张靖周, 李立国, 高潮.直升机排气系统红外抑制器的模型实验研究[J].红外与毫米波学报, 2005, 24(2):125-129. ZHANG Jingzhou, LI Liguo, GAO Chao.Model experiments of infrared suppressor for helicopter exhaust system[J].Journal of Infrared Milim Waves, 2005, 24(2):125-129.(in Chinese) [16] 刘友宏, 陈锵, 李立国.圆排波瓣圆柱混合管的气动特性实验研究[J].南京航空航天大学学报, 2000, 32(4):375-380. LIU Youhong, CHEN Qiang, LI Liguo.Experimental investigation of internal aerodynamics of periodically axis-symmetry lobed exhaust-ejector mixers[J].Journal of Nanjing University of Aeronautics and Astronautics, 2000, 32(4):375-380.(in Chinese) [17] 单勇, 张靖周.波瓣喷管引射-混合器的数值研究与验证[J].推进技术, 2004, 25(4):320-324. SHAN Yong, ZHANG Jingzhou.Numerical computation and examination of a lobed mixer-ejector[J]. Journal of Propulsion Technology, 2004, 25(4):320-324.(in Chinese) [18] 陈懋章.粘性流体力学[M].北京:高等教育出版社, 2002.
点击查看大图
计量
- 文章访问数: 951
- HTML浏览量: 0
- PDF量: 747
- 被引次数: 0