摘要
超燃冲压发动机是吸气式高超声速飞行器的关键部件之一,超燃冲压发动机燃烧室内火焰结构的研究对揭示超声速燃烧的稳焰机理具有重要意义。利用平面激光诱导荧光(Planar Laser-Induced Fluorescence,PLIF)技术测量了超声速燃烧直连式试验台燃烧过程中重要自由基CH的二维分布,实现了超声速燃烧火焰放热区结构的可视化。在开敞空间的低速射流火焰炉中使用甲烷/空气预混火焰对CH-PLIF技术进行了初步验证和系统优化,再利用CH-PLIF技术在凹腔稳焰的超燃直连台上实现了超声速燃烧火焰放热区结构的二维可视化,并与OH-PLIF和CH自发辐射测量结果进行了对比。实验结果表明,在开敞空间的低速射流预混火焰中,火焰放热区会发生扭曲、褶皱和分裂等现象,随着雷诺数的增大,火焰锋面褶皱程度更加显著;在凹腔稳焰的超声速燃烧中,火焰放热区高度褶皱和破碎,放热区结构的厚度为0.5～6.5 mm,同时也存在放热区的分裂与剥离等现象。CH-PLIF技术能够以较高的空间分辨率更准确地呈现凹腔超声速火焰放热区的结构,其在凹腔稳焰的超声速燃烧诊断中具有重要的应用价值。
Scramjet engine is one of the most important components of air-breathing hypersonic vehicles,and the research on flame structures in the combustion chamber of scramjet engines plays a significant role in studying the mechanism of flame stabilization of the supersonic combustion.Two-dimensional distributions of CH were measured at a direct connect test facility using the PLIF(planar laser-induced fluorescence)technique to visualize the flame heat-release structures in a cavity-stabilized scramjet combustor.Verification and optimization of the CH-PLIF technique were conducted in a methane/air premixed low-speed flame generated by a jet flame burner.Two-dimensional distributions of flame heat-release structures in the scramjet combustor were achieved by using the CH-PLIF technique.OH-PLIF images and CH chemiluminescence images were also performed in the scramjet combustor to compare these images with the CH-PLIF images.Experimental results show that the heat-release zones of the low-speed premixed jet flames can become distorted,wrinkled and separated.The heat-release zones are highly wrinkled with the increasing Reynolds numbers.The heat-release zones with a thickness of 0.5~6.5 mm in the cavity-stabilized scramjet combustor become highly distorted and wrinkled,and the separation of the heat-release zones can be observed.It is found that the CH-PLIF technique is able to visualize the heat-release zones in cavity-stabilized scramjet combustors and can play a promising role in understanding cavity stabilization mechanisms of the supersonic combustion.
作者
梁剑寒
李韵
孙明波
吴戈
朱家健
高强
李博
LIANG Jianhan;LI Yun;SUN Mingbo;WU Ge;ZHU Jiajian;GAO Qiang;LI Bo(Science and Technology on Scramjet Laboratory,National University of Defense Technology,Changsha 410073,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《国防科技大学学报》
EI
CAS
CSCD
北大核心
2019年第1期27-33,共7页
Journal of National University of Defense Technology
基金
国家自然科学基金资助项目(51606217
91741205)
关键词
CH-PLIF
超声速燃烧
火焰结构
放热区
激光诱导荧光
湍流火焰
CH-PLIF
supersonic combustion
flame structure
heat-release zone
laser-induced fluorescence
turbulent flame
