三氧化二铝液滴对心碰撞直接数值模拟  

Direct Numerical Simulation of Head-on Binary Collision of Aluminum Oxide Droplets

作　　者：夏盛勇[1,2] 胡春波[1] 

机构地区：[1]西北工业大学燃烧、热结构与内流场重点实验室,西安710072 [2]剑桥大学工程系,英国剑桥

出　　处：《应用数学和力学》2014年第4期377-388,共12页Applied Mathematics and Mechanics

基　　金：国家自然科学基金(50976095)~~

摘　　要：为研究固体火箭发动机内三氧化二铝液滴碰撞的物理规律及结果预测模型，针对两个相同尺寸的三氧化二铝液滴对心碰撞，开展了直接数值模拟．首先进行了正十四烷液滴在氮气环境下的对心碰撞数值研究，数值与实验结果基本一致，验证了计算方法的可行性及准确性．针对三氧化二铝液滴开展了6MPa压强下不同Weber数的对心碰撞数值研究，计算Weber数范围为10-200，Ohnesorge数为0．0364；获得了反弹、大变形后聚合和自反分离3种结果类型，反弹与大变形后聚合的临界分离Weber数为26，大变形后聚合与自反分离的临界分离Weber数为44．根据临界Weber数对其他流体液滴碰撞模型进行修正，可以获得三氧化二铝液滴的碰撞模型．Direct numerical simulations of head-on binary collisions between equal-sized alumi- num oxide droplets were conducted to investigate the collision physics and mechanics of alumi- num oxide droplets in solid rocket motors. Trial simulations of head-on collisions of tetradecane droplets in nitrogen medium were performed firstly to give results in good agreement with those of the previous experiments. After the positive validation of the numerical method, the head-on binary collisions of equal-sized aluminum oxide droplets were numerically computed with vari- ous Weber numbers under 6 MPa ambient pressure and 3 387 K ambient temperature. The We- ber number ranged from 10 to 200, and the Ohnesorge number kept at 0.036 4, which covered three different types of outcomes： bouncing, coalescence and reflexive separation. The results show that the critical Weber number between bouncing and coalescence after substantial de- formation is 26, and the one between coalescence after substantial deformation and reflexive separation is 44. The collision model for aluminum oxide droplets can be obtained through mod- ification of the collision model for other fluid droplets with critical Weber numbers.

关 键 词：固体火箭发动机 三氧化二铝 液滴碰撞 直接数值模拟 自适应网格 VOF 

分 类 号：O242.1[理学—计算数学] O35[理学—数学]