超燃冲压发动机多凹腔燃烧室混合与燃烧性能定量分析

为从定量上研究超燃冲压发动机多凹腔燃烧室对增强混合、燃烧的影响,用大涡模拟方法和火焰面模型对燃料当量比为0.062的流场进行数值模拟。比较了不同多凹腔构型对混合效率、燃烧效率和总压损失的影响,并结合壁面压力分布、数值纹影解释了其原因。结果表明,凹腔串联、凹腔并联均能增强混合,混合效率最大可提高20.95%和9.52%;凹腔串联、凹腔并联均能增强燃烧,燃烧效率最大可提高14%和16.94%;燃烧时凹腔串联总压损失最小,但凹腔并联燃烧放热最快,对缩短燃烧室长度有利。

Quantitative Analysis of Mixing and Combustion in the Scramjet Multi-Cavity Combustor

In order to determine the influence of multi-cavity on mixing and combustion quantitatively,numerical investigation is carried out in a multi-cavity scramjet chamber with fuel equivalence ratio 0.825 by large eddy simulation and flamelet model.Mixing efficiency,combustion efficiency,and total pressure loss are compared.In addition,wall pressure distribution and numerical schlieren are given to explain the observed results.The analysis shows that the mixing and combustion are improved for cavities mounted in both tandem and parallel.The maximum increase in mixing efficiency can be up to 20.95% and 9.52%,while the combustion efficiency can increase up to 14% and 16.94%.Cavity mounting in tandem has the least total pressure loss in reacting case,while cavity mounting in parallel has the fast heat release,which is good for shortening chamber length.