H_2O污染对超燃冲压发动机燃烧室性能影响的三维数值模拟

Three-dimensional simulation of H_2O vitiation effects on combustor performance for scramjet

为了解来流污染对超燃冲压发动机性能的影响,需要大量的实验和CFD模拟。基于纯净空气和污染空气(H2O)来流下燃烧对比实验,采用较为详细的化学反应动力学模型(13组分33方程),对三个试验条件的燃烧室反应流场进行了三维大规模并行CFD模拟。模拟结果与对比试验测得的壁面压强比较接近,能"分辨"试验气体中H2O的污染影响。模拟结果显示,从燃烧室整体性能看,7.4%H2O和18.3%H2O污染导致燃烧室单位流量的空气对应推力分别下降4.1%和10.7%,而燃烧室燃烧效率分别下降5.5%和9.5%。

Understanding the complicated issues with regard to the effects of airstream vitiation on scramjet test performance requires a lot of efforts involving experiment,modeling and CFD simulation.Based on comparative experiments for combustion in clean air and air vitiated with H2O,massively parallel CFD simulations of reacting flowfield in the combustor for three cases corresponding to experimental conditions were conducted with a relatively detailed chemical kinetic model involving 13 species and 33 reactions.The simulated results are close to measured wall pressures of comparative experiments,and could ＂distinguish＂ the vitiation effects of H2O in test gas.The simulated results show that for overall performance of the combustor,7.4% H2O and 18.3%H2O contaminants of inflow decrease the thrust by 4.1% and 10.7% for unit air mass flow rate,and the combustion efficiency by 5.5%and 9.5%,respectively.