摘要
燃料的掺混均匀度是爆轰发动机起爆和爆轰波稳定传播的主要影响因素之一。为了探究不同燃烧室结构对吸气式旋转爆轰发动机内燃料与氧化剂掺混效果的影响,开展了爆轰发动机冷态流场三维数值模拟。采用密度基隐式格式求解三维N-S方程,以小孔进行燃料喷注的吸气式旋转爆轰发动机为模型,保持空气/乙烯的来流条件不变,分析了燃烧室入口扩张方式、凹腔燃烧室结构以及阻塞比对冷态流场掺混效果的影响。研究结果表明:燃烧室入口扩张方式的不同会影响超声速气流进入燃烧室形成的反射波结构,从而改变回流涡的位置,影响空气/乙烯的掺混效果;在燃烧室内壁面增加凹腔后,燃烧室头部的凹腔区域形成的低速回流区会卷吸流经的气体,可明显改善双侧扩张和内侧扩张型燃烧室的掺混效果;增加阻塞比,空气主流速度降低,凹腔内回流涡影响区域增大,空气与乙烯在燃烧室内掺混位置前移,掺混效果提升。
The mixing characteristic of the fuel is one of the main factors affecting the ignition of the rotating detonation engine and the stable propagation of the detonation wave.In order to investigate the effects of different combustor structures on the cold flow mixing of fuel and oxidant in air-breathing rotating detonation engine,a three-dimensional numerical simulation of the cold flow field was carried out.The density-based implicit format solver was adopted to solve the three-dimensional N-S equations.Based on the air-breathing rotating detonation engine with fuel injected from the small holes,the inflow conditions of air and ethylene remained unchanged,and the effect of area-expansion structure of combustor,cavity structure and blocking ratio on the cold flow mixing was analyzed.The results show that different area-expansion strucures will affect the reflected wave structure formed by the supersonic airflow entering combustor,thereby changing the position of the recirculation vortex and affecting the mixing of air/ethylene.The mixing effect of the double-sided expansion and inner expansion combustor improve may be by adding a cavity on the inside of the combustor when ethylene through the low velocity area of the cavity.After increasing the blocking ratio,the velocity of the main air flow decreases,the influence area of the recirculation vortex in the cavity becomes larger,and the air and ethylene begin to be mixed at the front position of the combustion chamber,and the mixing effect is improved.
作者
曹琦
郑权
肖强
冯文康
翁春生
续晗
CAO Qi;ZHENG Quan;XIAO Qiang;FENG Wenkang;WENG Chunsheng;XU Han(National Key Lab of Transient Physics,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《弹道学报》
CSCD
北大核心
2023年第2期36-45,共10页
Journal of Ballistics
基金
瞬态物理国家重点实验室基金(6142604210202)。
关键词
爆轰发动机
扩张结构
凹腔
回流涡
冷流掺混
rotating detonation engine
area-expansion structure
cavity
recirculation vortex
cold flow mixing
