凹腔超声速燃烧室氢气燃烧流场数值模拟

对带长深比为10的凹腔结构的燃烧室二维氢燃烧流场进行数值模拟,燃料喷注方式采用凹腔上游喷注加辅加凹腔前壁、底壁、后壁喷注。采用三阶MUSCL格式求解二维含组分守恒N-S方程组,湍流模型采用剪切修正的RNGk-ε湍流模型,对喷氢燃烧工况进行了计算研究,并分别分析了凹腔中不同燃料喷注方式对燃烧特性的影响。结果表明：凹腔是火焰驻留的主要区域;凹腔上游喷注氢,可以使燃料在凹腔中混合燃烧,辅加凹腔中喷氢的三种方式对燃烧状况产生一定的影响。在凹腔前壁、底面辅加喷氢,没有增强凹腔的稳焰特性,对整个燃烧状态影响不大;在凹腔后壁喷氢,能够增加凹腔中的燃料含量,加强了回流效果,对燃烧状态影响较大。三种喷注方式都没有从根本上改变凹腔燃烧流场的特性。

Numerical simulation of hydrogen combustion on flow field in supersonic combustor with cavity

The flow fields of hydrogen burning in scramjet combustion chamber with length depth ratio cavities were simulated numerically by using the element-conservation Navier-Stokes equations with the RNG k-ε two-equation turbulence model. The injection schemes are cavity upstream injection with front wall, bottom and back wall injection assisted. The fuel burning features for different injection schemes were analyzed. The conclusions are as follows： the cavity is the pri- mary area of flame holding; upstream cavity injection of the hydrogen can finish the process of mix- ing and burning; the assistant injections can affect the flow fields. When adding the injection on front wall and bottom of cavity, the flame holding is not enhanced, and the burning case is scarcely changed; When adding the injection on the back of cavity, it increases the fuel in cavity and strengthens the circumfluence effect, the affect to burning case is obvious. The flow fields features are not radically changed by the three assistant injection schemes.