直管内胞格爆轰的基元反应数值研究  

Numerical study on cellular detonation in a straight tube based on detailed chemical reaction model

作　　者：王昌建[1] 徐胜利[1] 

机构地区：[1]中国科学技术大学力学和机械工程系

出　　处：《爆炸与冲击》2005年第5期405-416,共12页Explosion and Shock Waves

基　　金：国家自然科学基金项目(10172083);中国工程物理研究院和国家基金委联合基金项目(10076018);北京理工大学爆炸科学与技术国家重点实验室开放基金项目(KFJJ03-2)

摘　　要：基于基元反应和二维欧拉方程,对直管内胞格爆轰进行了数值模拟。采用5阶WENO(we ightedessentially nonosc illatory schem e)求解对流项,采用2阶附加半隐的龙格-库塔法处理化学反应源相引起的刚性。获得了密度、压力、温度和典型组元质量分数流场及数值胞格结构等。结果表明:网格精度的差异明显影响胞格的规则性和爆轰的平衡模数,随着网格尺度的减小,胞格由不规则变为规则。预混气组成、初压、初温及管道宽度给定,三波点数收敛为确定值。足够强度的初始扰动可再现胞格爆轰,最终形成的自持胞格爆轰模数与初始扰动的形状、大小、位置均无关。沿胞格中心线,爆轰波速度变化范围为0.88DC J^1.5DC J,爆轰波平均速度与CJ爆轰速度仅偏差0.88%。峰值压力与初压之比为14~50。计算爆轰波平均速度、胞格宽长比与实验值基本一致,但计算胞格宽度比实验值略小。数值模拟加深了对横波的产生和发展、未反应气囊、爆轰胞格的二次起爆等胞格爆轰特性的认识。Cellular detonation in a straight tube was numerically studied, based on two-dimensional reactive Euler equations and detailed chemical reaction model. The 5th order WENO scheme was employed to resolve the convective terms, and the additive semi-implicit Runge-Kutta methods was used to treat the stiffness caused by the chemical source terms. The contours of density, pressure, temperature and typical species mass fraction as well as numerical cellular pattern etc. were obtained. The results show that, the different grid resolutions evidently influence the regularity of detonation cells and the equilibrium detonation mode number. As grid size increases, the detonation wave developes more irregular cells and more additional triple points. For the given gas mixtures, initial pressure, initial temperature and tube width, the final self-sustaining detonation mode number is converged to a fixed value. It is also independent of the variety of initial perturbations, provided that the initial perturbations are sufficiently strong to reproduce the self-sustaining cellular detonation. Detonation velocity ranges from 0.88DCJ to 1.5DCJ along the cell centerline, and the average detonation speed is only 0.88% different from the CJ value. The ratio of peak pressure to initial pressure ranges from 14 to 50 along the cell centerline. The average detonation speed and cell aspect ratio are remarkably agreeable with experimental values, but the computational cells are slightly smaller than the experimental cells. Some complicated detonation physics including transverse waves, un-reacted gas pocket, re-initiation of detonation cells etc. was recognized.

关 键 词：爆炸力学 基元反应 数值模拟 胞格爆轰 二次起爆 胞格结构 

分 类 号：O381[理学—流体力学]