摘要
为了揭示高空低压环境下底排减阻率减小的机理,建立底排装置尾部流场的化学非平衡流数学物理模型。其中二次燃烧模型采用10组分25步反应的H2-CO燃烧模型,运用统一算法的思路编程求解二维轴对称方程组,对底排尾部流场进行数值模拟。模拟结果和实验进行对比验证,基本吻合。在此基础上,对底排尾部流场以及燃烧特性进行数值预测,研究环境压力降低对底排尾部二次燃烧的影响。结果表明:二次燃烧对底部加能的贡献是热排气的6.4倍,是底排加能减阻的关键;随着环境压力的降低,模型尾部的环状回流区内H2的燃烧效率逐渐降低,中间产物H逐渐增多,燃烧逐渐变得不充分,导致底排减阻率明显下降。
In order to investigate the mechanism of the decrease in drag reduction rate of base bleed in the subatmospheric pressure, a mathematical and physical model about the base flow with chemical non- equilibrium of base bleed is established. H2-CO combustion model which consists of 10 components and 25 reactions is used for secondary combustion. Two-dimensional axisymmetric equations are programmati- cally computed using a set of uniform numerical process methods. The base flow field of base bleed is simulated. Simulation results are validated with experiment data. On this basis, the base flow field and combustion characteristics are numerically predicted. The results show that the added energy released from secondary combustion is 6.4 times of the added energy of hot base bleed. Secondary combustion is a key for energy increase and drag reduction. With the decrease of the ambient pressure, the combustion efficiency of H2 decreases gradually in the annular recirculation zone of the tail of the model,meanwhile the intermediate product of H increases gradually. These make the secondary combustion become more and more insufficiency, resulting in decreasing significantly the drag reduction rate of base bleed.
出处
《兵工学报》
EI
CAS
CSCD
北大核心
2015年第3期443-450,共8页
Acta Armamentarii
基金
国家自然科学基金项目(51176076)
关键词
兵器科学与技术
底部排气
二次燃烧
数值模拟
尾部流场
化学非平衡流
ordnance science and technology
base bleed
secondary combustion
numerical simulation
base flow field
chemical non-equilibrium flow
