Large Eddy Simulation of Recirculation and Precessing Vortex Core in Swirling Flow Around a Bluff-Body

Journal of Propulsion Technology ›› 2014, Vol. 35 ›› Issue (8): 1070-1079.

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Large Eddy Simulation of Recirculation and Precessing Vortex Core in Swirling Flow Around a Bluff-Body

Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,China;Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,China;Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,China;Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,China

Published:2021-08-15

钝体绕流有旋流中回流区与进动涡核的大涡模拟

张济民,韩　超,张宏达,叶桃红

中国科学技术大学热科学与能源工程系,安徽合肥 230027;中国科学技术大学热科学与能源工程系,安徽合肥 230027;中国科学技术大学热科学与能源工程系,安徽合肥 230027;中国科学技术大学热科学与能源工程系,安徽合肥 230027

作者简介:张济民(1985—),男,博士生,研究领域为旋流的大涡模拟。E-mail:zhangjim@mail.ustc.edu.cn 通讯作者:叶桃红(1966—),男,博士,副教授,研究领域为湍流燃烧。
基金资助:
国家自然科学基金(51176178)；国家自然科学重点基金(50936005)。

Abstract

Abstract: The non-reactive flow fields of the Sydney swirl burner were studied with large eddy simulation (LES) under four swirl numbers 0.57,0.68,0.91 and 1.59. Smagorinsky eddy viscosity model with dynamic procedure was selected as the sub-grid scale turbulence model to investigate the flow structures,precession frequency and precessing vortex core (PVC) under different swirl numbers. The shortest bluff-body stabilized recirculation zone appears under swirl number 0.68. With increasing of swirl number,the swirl shear layer at the central jet nozzle damps gradually,while the one in downstream region strengthens. Power spectrum analysis indicates that the appearance and vanishment of precession motion coincide with the enhancement and attenuation of swirl shear layer,respectively. The central jet and downstream region have different precession frequency. This result indicates the existence of two independent large-scale vortices structures and it is further proofed by the correlation analysis of circumferential velocity at different probe locations. The distribution of instantaneous streamlines and pressure on the cross section at axial position of 70 mm indicates the existence of PVC in downstream region. The iso-surface of instantaneous pressure displays the spiral structure of PVC at the central jet exit and in downstream region. The downstream PVC is orthogonal to the streamlines of mean velocity. This fact demonstrates that the PVC is generated by Kelvin-Helmholtz shear layer instability.

Key words: Sydney swirl burner; Large eddy simulation; Bluff-body; Recirculation; Precession frequency; Precessing vortex core

摘要： 针对旋流数为0.57、0.68、0.91和1.59四种工况下的悉尼旋流燃烧器的冷态流场进行了大涡模拟,选取动态Smagorinsky涡黏模型作为亚格子尺度的湍流模型,研究不同旋流数下的流场结构、进动频率和进动涡核。模拟结果表明,旋流数为0.68时,钝体回流区长度最短。随着旋流数的增加,中心射流出口的旋流剪切层不断衰减,而下游的旋流剪切层不断增强。功率谱分析表明,进动现象的出现和消失对应于与旋流剪切层的增强和衰减；中心射流与下游区域具有不同的进动频率,表明流场中存在着两个独立的大尺度涡旋结构。不同取值位置的周向速度相关性分析进一步佐证了两个涡旋结构的存在。轴向位置70 mm处的横截面上瞬时流线和压强分布证实了下游流场存在着进动涡核。瞬时压强等值面显示了中心射流出口和下游流场进动涡核的三维螺旋形结构。下游流场的进动涡核均与平均速度场流线在空间上成正交关系,表明进动涡核是由剪切层Kelvin-Helmholtz不稳定性产生。

关键词: 悉尼旋流燃烧器；大涡模拟；钝体；回流区；进动频率；进动涡核

ZHANG Ji-min,HAN Chao,ZHANG Hong-da,YE Tao-hong. Large Eddy Simulation of Recirculation and Precessing Vortex Core in Swirling Flow Around a Bluff-Body[J]. Journal of Propulsion Technology, 2014, 35(8): 1070-1079.

张济民,韩　超,张宏达,叶桃红. 钝体绕流有旋流中回流区与进动涡核的大涡模拟[J]. 推进技术, 2014, 35(8): 1070-1079.

References

[1] Syred N,Beér J M.Combustion in Swirling Flows: a Review[J].Combustion and Flame,1974,23(2): 143-201.
[2] Lucca-Negro O,O'Doherty T.Vortex Breakdown: a Review[J].Progress in Energy and Combustion Science,2001,27(4): 431-481.
[3] O'Doherty T,Griffiths A J,Syred N,et al.Experimental Analysis of Rotating Instabilities in Swirling and Cyclonic Flows[J].Developments in Chemical Engineering and Mineral Processing,1998,7(3-4): 245-268.
[4] Syred N.A Review of Oscillation Mechanisms and the Role of the Precessing Vortex Core (PVC) in Swirl Combustion Systems[J].Progress in Energy and Combustion Science,2006,32(2): 93-161.
[5] Escudier M.Vortex Breakdown: Observations and Explanations[J].Progress in Aerospace Science,1988,25(2): 189-229.
[6] Esquva-Dano I,Nguyen H T,Escudie D.Influence of a Bluff-Body's Shape on the Stabilization Regime of Non-Premixed Flames[J].Combustion and Flame,2001,127(4): 2167-2180.
[7] Ge B,Zang S S.Experimental Study on the Interactions for Bluff-Body and Swirl in Stabilized Flame Process[J].Journal of Thermal Science,2012,21(1): 88-96.
[8] Al-Abdeli Y M,Masri A R.Recirculation and Flowfield Regimes of Unconfined Non-Reacting Swirling Flows[J].Experimental Thermal and Fluid Science,2003,27(5): 655-665.
[9] Al-Abdeli Y M,Masri A R.Precession and Recirculation in Turbulent Swirling Isothermal Jets[J].Combustion Science and Technology,2004,176(5-6): 645-665.
[10] Masri A R,Kalt P A M,Barlow R S.The Compositional Structure of Swirl-Stabilized Turbulent Nonpremixed Flames[J].Combustion and Flame,2004,137(1-2): 1-37.
[11] Al-Abdeli Y M,Masri A R,Marquez G R,et al.Time Varying Behaviour of Turbulent Swirling Nonpremixed Flames[J].Combustion and Flame,2006,146(1-2): 200-214.
[12] Al-Abdeli Y M,Masri A R.Stability Characteristics and Flowfields of Turbulent Non-Premixed Swirling Flames[J].Combustion Theory and Modeling,2003,7(7): 731-766.
[13] Masri A R,Kalt P A M,Al-Abdeli Y M,et al.Turbulent-Chemistry Interactions in Non-Premixed Swirling Flames[J].Combustion Theory and Modeling,2007,11(5): 653-673.
[14] 张兆顺,崔桂香,许春晓.湍流大涡数值模拟的理论和应用[M].北京:清华大学出版社,2008.
[15] Malalasekera W,Ranga-Dinesh K K J,Ibrahim,S S,et al.Large Eddy Simulation of Isothermal Turbulent Swirling Jets[J].Combustion Science and Technology,2007,179(8): 1481-1525.
[16] Ranga-Dinesh K K J,Kirkpatrick M P.Study of Jet Precession,Recirculation and Vortex Breakdown in Turbulent Swirling Jets Using LES[J].Computers & Fluids,2009,38(6): 1232-1242.
[17] Yang Y,Kaer S K.Large-Eddy Simulations of the Non-Reacting Flow in the Sydney Swirl Burner[J].International Journal of Heat and Fluid Flow,2012,36: 47-57.
[18] 胡瓅元,罗永浩,周力行.两种亚网格湍流模型的旋流扩散火焰大涡模拟[J].清华大学学报(自然科学版),2007,47(5): 742-745.
[19] Kempf A,Malalasekera W,Ranga-Dinesh K K J,et al.Large Eddy Simulations of Swirling Non-Premixed Flames with Flamelet Models: a Comparison of Numerical Methods[J].Flow Turbulence Combustion,2008,81(4): 523-561.
[20] Ranga-Dinesh K K J,Jenkins K W,Kirkpatrick M P,et al.Identification and Analysis of Instability in Non-Premixed Swirling Flames Using LES[J].Combustion Theory and Modeling,2009,13(6): 947-971.
[21] Piomelli U,Liu J.Large Eddy Simulation of Rotating Channel Flows Using a Localized Dynamic Model[J].Physics of Fluids,1995,7(4): 839-848.
[22] Issa R I.Solution of the Implicitly Discretised Fuid Flow Equations by Operator-Splitting[J].Journal of Computation Physics,1986,62(1): 40-65.
[23] Jones W P,Lyra S,Navarro-Martinez S.Large Eddy Simulation of Turbulent Confined Highly Swirling Annular Flows[J].Flow Turbulence and Combustion,2012,89(3): 361-384.
[24] García-Villalba M,Fr?hlich J,Rodi W.Identification and Analysis of Coherent Structures in the near Field of a Turbulent Unconfined Annular Awirling Jet Using Large Eddy Simulation[J].Physics of Fluids,2006,18(5): 10-17.
[25] Jeong J,Hussain F.On the Identification of a Vortex[J].Journal of Fluid Mechanics,1995,285: 69-94.(编辑:史亚红)收稿日期:2013-08-06；修订日期:2013-09-24。基金项目:国家自然科学基金(51176178)；国家自然科学重点基金(50936005)。作者简介:张济民(1985—),男,博士生,研究领域为旋流的大涡模拟。E-mail:zhangjim@mail.ustc.edu.cn通讯作者:叶桃红(1966—),男,博士,副教授,研究领域为湍流燃烧。E-mail:thye@ustc.edu.cn

Large Eddy Simulation of Recirculation and Precessing Vortex Core in Swirling Flow Around a Bluff-Body

钝体绕流有旋流中回流区与进动涡核的大涡模拟

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