超声速条件下燃料和空气之间的高效混合是超然冲压发动机技术上的主要挑战。基于大涡模拟和流动稳定性分析，针对超声速尾迹-剪切流动开展了混合增强方法研究。尾迹的存在改变了混合层流动的速度剖面，对流动稳定性产生了重要影响，使混合层由三维最不稳定变为二维最不稳定，最不稳定扰动波频率和增长率增大。基于流动稳定性结果引入扰动的混合增强方式依然有效，根据稳定性结果设计了波纹隔板。数值结果表明：二维波纹壁引入的扰动未能增长，不具备混合强化效果，而三维波纹壁引入的扰动能够快速增长，具有混合强化效果，且波纹壁参数越接近最不稳定扰动波参数，混合强化效果越明显。
The efficient mixing of fuel and air at supersonic speed is the main challenge of scramjet technology. Based on analysis of large eddy simulation and hydrodynamic stability, the methods of mixing enhancement are studied in the supersonic wake shear flow. The existence of a wake component alters the profile of mean velocity, and has an important influence on the hydrodynamic stability. The existence of a wake component makes the most unstable modes of mixing layer from the three-dimensional to the two-dimensional, and the frequency and growth rate of the most unstable wave increase. The method of mixing enhancement of introducing disturbances in the mixing layer is still effective based on the analysis of hydrodynamic stability. According to the stability analysis, the parameters of wavy wall are designed. The numerical simulations observe that the disturbance introduced by the two-dimensional wavy wall cannot grow and almost has no mixing enhancement effect, while the disturbance introduced by the three-dimensional wavy wall can grow rapidly and has mixing enhancement effect. The closer the parameter of the wavy wall is to the parameter of the most unstable disturbance, the more obvious the mixing enhancement effect is.
[1] SEINER J M, DASH S M, KENZAKOWSKI D C. Historical survey on enhanced mixing in scramjet engines[J]. Journal of Propulsion and Power, 2001, 17(6):1273-1286.
[2] SUN Z Z, SCARANO F, VAN OUDHEUSDEN B W, et al. Numerical and experimental investigations of the supersonic microramp wake[J]. AIAA Journal, 2014, 52(7):1518-1527.
[3] ZHANG Y J, LIU W D, SUN M B. Effect of microramp on transverse jet in supersonic crossflow[J]. AIAA Journal, 2016, 54(12):4041-4045.
[4] BRINKERHOFF J R, ORIA H, YARAS M I. Experimental and computational study of mixing mechanisms in an axisymmetric lobed mixer[J]. Journal of Propulsion and Power, 2013, 29(5):1017-1030.
[5] 张冬冬, 谭建国, 李浩, 等. 基于三角波瓣混合器的超声速流场精细结构和掺混特性[J]. 物理学报, 2017, 66(10):104702. ZHANG D D, TAN J G, LI H, et al. Fine flow structure and mixing characteristic in supersonic flow induced by a lobed mixer[J]. Acta Physica Sinica, 2017, 66(10):104702(in Chinese).
[6] BURNES R, PARR T, WILSON K, et al. Investigation of supersonic mixing control using cavities:Effect of fuel injection location:AIAA-2000-3618[R]. Reston:AIAA, 2000.
[7] ZANG A, TEMPEL T, YU K, et al. Experimental characterization of cavity-augmented supersonic mixing:AIAA-2005-1423[R]. Reston:AIAA, 2005.
[8] SHI H T, WANG G L, LUO X S, et al. Large-eddy simulation of a pulsed jet into a supersonic crossflow[J]. Computers & Fluids, 2016, 140:320-333.
[9] ZHAO M J, YE T H. URANS study of pulsed hydrogen jet characteristics and mixing enhancement in supersonic crossflow[J]. International Journal of Hydrogen Energy, 2019, 44(36):20493-20503.
[10] BARZEGAR GERDROODBARY M, MORADI R, TLILI I. The influence of upstream wavy surface on the mixing zone of the transverse hydrogen jet at supersonic free stream[J]. Aerospace Science and Technology, 2019, 94:105407.
[11] LI Z X, MANH T D, BARZEGAR GERDROODBARY M, et al. The effect of sinusoidal wall on hydrogen jet mixing rate considering supersonic flow[J]. Energy, 2020, 193:116801.
[12] TAN J G, ZHANG D D, LV L. A review on enhanced mixing methods in supersonic mixing layer flows[J]. Acta Astronautica, 2018, 152:310-324.
[13] HUANG W, DU Z B, YAN L, et al. Supersonic mixing in airbreathing propulsion systems for hypersonic flights[J]. Progress in Aerospace Sciences, 2019, 109:100545.
[14] 黄伟, 杜兆波. 超声速流动中燃料混合增强方法研究进展[J]. 航空兵器, 2020, 27(4):1-10. HUANG W, DU Z B. Progress in research on mixing enhancement approaches in supersonic crossflow[J]. Aero Weaponry, 2020, 27(4):1-10(in Chinese).
[15] 郭欣, 王强. 基于PSE的单股剪切混合流稳定性分析[J]. 航空学报, 2011, 32(8):1411-1420. GUO X, WANG Q. Stability analysis of single-stream shear mixing layer based on parabolized stability equations[J]. Acta Aeronautica et Astronautica Sinica, 2011, 32(8):1411-1420(in Chinese).
[16] YANG W B, ZHUANG F G, SHEN Q, et al. Experimental and numerical study on instability structure of the supersonic mixing layer (Mc=0.5)[J]. Science in China Series G:Physics, Mechanics and Astronomy, 2009, 52(10):1624-1631.
[17] URBAN W D, MUNGAL M G. Planar velocity measurements in compressible mixing layers[J]. Journal of Fluid Mechanics, 2001, 431:189-222.
[18] 罗纪生, 吕祥翠. 超音速混合层稳定性分析及增强混合的研究[J]. 力学学报, 2004, 36(2):202-207. LUO J S, LÜ X C. Investigation on stability of 3-d supersonic mixing layer and method of enhancing the mixing[J]. Acta Mechanica Sinica, 2004, 36(2):202-207(in Chinese).
[19] 郑忠华, 范周琴, 王子昂, 等. 流场可压缩性对涡相互作用影响的数值研究[J]. 航空学报, 2020, 41(2):123295. ZHENG Z H, FAN Z Q, WANG Z A, et al. Numerical study of compressibility effect on flowfield evolution of vortex interaction[J]. Acta Aeronautica et Astronautica Sinica, 2020, 41(2):123295(in Chinese).
[20] WALLACE D, REDEKOPP L G. Linear instability characteristics of wake-shear layers:AIAA-1991-1644[R]. Reston:AIAA, 1991.
[21] ZHUANG M, DIMOTAKIS P E. Instability of wake-dominated compressible mixing layers[J]. Physics of Fluids, 1995, 7(10):2489-2495.
[22] MARTINI E, CAVALIERI A V G, JORDAN P. Acoustic modes in jet and wake stability[J]. Journal of Fluid Mechanics, 2019, 867:804-834.
[23] YANG R, WANG Z G, WU J P. Instability of an asymmetric supersonic planar wake[J]. Acta Astronautica, 2020, 173:86-90.
[24] MAYER C S J, VON TERZI D A, FASEL H F. Direct numerical simulation of complete transition to turbulence via oblique breakdown at Mach 3[J]. Journal of Fluid Mechanics, 2011, 674:5-42.
CJA