旋转爆轰发动机燃烧室掺混特性数值研究

旋转爆轰发动机燃烧室掺混特性数值研究

徐雪阳,武晓松,卓长飞,马虎

(南京理工大学 机械工程学院,南京 210094)

摘要:为探索旋转爆轰发动机燃烧室内气体射流冷流掺混的情况,采用高精度高分辨率迎风通量分裂格式(AUSMPW+),求解三维欧拉方程。以环缝/小孔喷注方式的发动机模型为基础,在保证当量比不变情况下,分析了燃料喷注位置、喷注角度、单侧孔或双侧孔喷注、入口总压及出口反压对冷流掺混效果的影响。研究结果表明:随着H2喷注位置的前移,掺混效果有明显提高;喷注角度的改变对H2/Air的掺混效果有很大的影响;顺喷的掺混均匀度变化幅度较大,在燃烧室的头部,顺喷的掺混效果比垂直喷注和逆喷差,在燃烧室尾部的掺混效果优于其他2种;对单侧孔或双侧孔喷注而言,双侧孔喷注方式的掺混效果明显高于单侧孔喷注方式;掺混效果与入口总压成反比,与出口反压成正比。

关键词:流体力学;旋转爆轰发动机;掺混;喷注;数值仿真

中图分类号:TJ303.4文献标识码:A

Numerical Simulation of Mixing Characteristics in Rotating Detonation Engine Combustor

XU Xue-yang,WU Xiao-song,ZHUO Chang-fei,MA Hu

(School of Mechanical Engineering,NUST,Nanjing 210094,China)

Abstract:In order to research the mixing effect of the gas jet in the combustion of rotating detonation engine,three dimensional Euler equations were solved by high-resolution upwind flux split scheme(AUSMPW+).Based on an engine model with slot/hole injection mode,the effects of jetting parameters on mixing effectiveness were analyzed under the same equivalence ratio,such as different fuel injection position,injection angle,and unilateral or bilateral injection,inlet stagnation pressure and back pressure.As the injection position moves forward,the H2/Air mixing effect obviously improves.The change of the injection angle has a great influence on mixing effectiveness.Due to the large variations of the mixing uniformity with forward injection,the mixing effect in the first half of distance of the combustion chamber is worse than that of vertical injection and reverse injection,but it is better than the other two in the second half.For the injection method through unilateral and bilateral injection holes,the mixing effect of injection with holes from double side is significantly better than that of the unilateral injection.The mixing effectiveness is inversely related to inlet stagnation pressure,and it is proportional to back pressure.

Key words:fluid mechanics;rotating detonation engine;mixing;injection scheme;numerical simulation

旋转爆轰发动机(rotating detonation engine,RDE)是一种利用爆轰波在环形燃烧室内连续旋转传播的发动机。RDE的概念最早由Voitsekhovskii[1-2]等人于20世纪60年代提出。1966年Nicholls[3-4]等人完成了RDE可行性验证。与传统的脉冲爆轰发动机(pulse detonation engine,PDE)相比,RDE除了具有PDE的优点(如热循环效率高,推重比大,比冲大,单位燃料消耗率(SFC)低,工作范围宽,可以用吸气式和火箭式2种模式工作等)外,还克服了PDE工作频率低(单管一般不超过100 Hz)、对点火系统要求高(每个循环都需点火)等缺点。……