含化学反应膛口流场的无网格数值模拟  

Numerical simulation of a muzzle flow field involving chemical reactions based on gridless method

作　　者：吴伟[1] 许厚谦[1] 王亮[1] 薛锐[1] 

机构地区：[1]南京理工大学能源与动力工程学院,江苏南京210094

出　　处：《爆炸与冲击》2015年第5期625-632,共8页Explosion and Shock Waves

摘　　要：基于无网格方法,对包含大位移运动边界和非平衡化学反应的膛口流场进行了数值模拟。所发展算法是基于线性基函数最小二乘显式无网格方法,忽略黏性及湍流的影响,对流场采用ALE(arbitrary Lagrangian-Eulerian)形式的Euler方程描述,对流通量和化学反应源项采用多组分HLLC(Harten-Lax-van Leer-Contact)格式和有限速率反应模型计算,对于运动边界造成的点云畸形采用局部点云重构方法处理,重构过程中采用虚拟边阵面推进。对圆柱绕流和激波诱导燃烧流场进行了数值模拟,验证了重构方法和化学反应计算的有效性。最后对12.7mm口径机枪膛口流场进行了模拟,结果同实验照片、非结构网格方法结果吻合较好,数值结果清晰地再现了膛口初始冲击波、膛口冲击波、欠膨胀射流波系结构的动力学发展过程,以及膛口焰的时间、空间分布特征。A gridless method for simulation of reactive flows involving moving boundaries was investi- gated based on the linear basis least-squares gridless method. The Euler equations of arbitrary La- grangian-Eulerian form were employed as governing equations. The numerical flux and chemical sources were calculated by the multi-component HLLC （（Harten-Lax-van Leer-Contact） scheme and finite rate reaction model, respectively. An elevated restructuring technique of local cloud was adopt- ed to deal with the moving boundaries. The front advance method of fictitious boundaries was used during the restructuring. The flow around the cylinder and the shock-induced combustion flow field were simulated to validate the accuracy firstly. The muzzle flow of a 12.7 mm machine gun was simu- lated. The computational shadowgraphs agree well with the experimental photographs, the density and pressure contours are in agreement with the results by the unstructured mesh method. The nu- merical results show the coupling and interaction progress in the initial muzzle flow field, the under- expanding jet of explosive gas and high-speed projectile clearly, and the temporal, spatial distribution characteristics of the muzzle flash are reappeared plainly.

关 键 词：爆炸力学 动态点云 无网格方法 膛口流场 非平衡反应流 

分 类 号：O381[理学—流体力学]