Abstract: In order to investigate the effects of the secondary combustion on the drag reduction rate of base bleed，a H2-CO combustion model which consists 8 components and 12 reactions was used for the secondary combustion simulations. Two-dimensional axisymmetric equations were programmatically computed using a set of uniform numerical process methods. The base flow with chemical non-equilibrium of base bleed was simulated. The base pressure of the base bleed equipment with different injection parameters of the simulations were basically in agreement with the experimental data. The results show that the base pressure of the base bleed equipment first increases rapidly with the increase of the injection parameters I. When the injection parameters I reaches 0.007，the growth of the base pressure gradually slows. When I=0.01～0.015，the base pressure is basically unchanged with the increase of the I，and the effect of drag reduction with base bleed is best. When the injection temperature Tj≤1025K，the drag reduction rate of base bleed is relatively small，because the secondary combustion has not happened in the base region of the base bleed equipment. When 1025K1100K，the secondary combustion is complete. The injection temperature of the base bleed equipment should be larger than 1100K.

Key words: Fluid mechanics；Base bleed；Secondary combustion；Numerical simulation；Base flow field；Chemical non-equilibrium flow

摘要： 为了研究二次燃烧对底排增压减阻的影响，采用8组分12步反应的H2-CO燃烧模型作为二次燃烧模型，运用统一算法的思路编程求解二维轴对称多组分N-S方程，对底排装置尾部化学非平衡流进行数值模拟。底排装置的底压随排气参数变化的模拟结果和现有实验数据比较吻合。数值模拟结果表明:底排装置底部压力随着排气参数I的增加先迅速增大，当I达到0.007时，底压增长速度逐渐变慢，在I=0.01～0.015的范围内底压基本不变，此时底排增压减阻的效果最好。当排气温度Tj≤1025K时，底排装置尾部没有发生二次燃烧，底排减阻率相对较小。当1025K1100K时，二次燃烧充分。底排装置的排气温度应大于1100K。

关键词: 流体力学；底部排气；二次燃烧；数值模拟；尾部流场；化学非平衡流