超级燃烧室混合室掺混特性数值研究

Numerical Study of Mixing Characteristics in Hyper-burner Mixing Chamber

关键词:  超级燃烧室  波瓣混合器  总压恢复系数  热混合效率  动量混合系数

Key words:  Hyper-burner  Lobed mixer  Total pressure recovery coefficient  Thermal mixing efficiency  Momentum mixing coefficient

摘要:

为了满足TBCC超级燃烧室的各工作模式下的低阻高效混合,设计了两种采用方形波瓣混合器和结构可调的导流片相结合的强化掺混方案。方案A由上下扩张角不等的波瓣混合器和处于波谷上方的离散状导流片组成,波瓣混合器正对于分流环；方案B由全环形导流片和上下等扩张角的波瓣混合器组成,波瓣混合器的中径小于分流环直径。通过数值研究对比分析了两种混合方案的流动特征发现,两种方案都未出现倒流和流动分离现象；除冲压模态时的波峰截面方案B的流线分布较为理想外,其它工作状态下方案A波峰和波谷截面流线分布均优越方案B。通过对总压恢复系数、热混合效率及动量混合系数的对比发现,混合方案A在飞行Ma=0～3的各工作状态下的总压恢复系数均高于方案B,最多高3.5%,且能在较短的掺混距离内使内外涵气流的温度和速度混合均匀。考虑到兼顾飞行Ma=0～3范围内的低阻高效混合要求,方案A具有良好的强化掺混特性。

Abstract:

Two enhanced mixing schemes were proposed to achieve high mixing efficiency and low resistance in the turbine based combined cycle hyper-burner in all the operating modes using square lobed mixer combined with adjustable deflectors. Scheme A is composed of the scattered deflectors located just above the trough and the unequal penetration angle of lobed mixer located directly behind the split ring. While,scheme B is composed of the annular deflector and equal penetration angle of lobed mixer in which diameter is less than the split ring. The flow characteristics of these two mixing schemes was numerically simulated. The results indicate that the appearance of reflow blockage and flow separation were not observed for both schemes. Apart from the streamline distribution of scheme B at the peak section better at ramjet mode,the streamline distribution of scheme A at the peak and though section was superior to scheme B at other modes. With comparing of the total pressure recovery coefficient,thermal mixing efficiency and momentum mixing coefficient,it is found that the total pressure recovery coefficient of scheme A is 3.5% higher than that of scheme B with flight Mach number from 0 to 3. Furthermore,scheme A provides a uniform-mixed velocity and temperature in a shorter mixing distance. On the whole,the mixing scheme A has superior enhanced mixing features in flight Mach number from 0 to 3.