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| 剪切稀化非牛顿射流撞击液膜破碎直接数值模拟 | |
| 引用本文： | 朱呈祥,吴猛,陈荣钱,尤延铖. 剪切稀化非牛顿射流撞击液膜破碎直接数值模拟[J]. 航空学报, 2018, 39(5): 121982-121982. DOI: 10.7527/S1000-6893.2018.21982 |
| 作者姓名： | 朱呈祥 吴猛 陈荣钱 尤延铖 |
| 作者单位： | 厦门大学 航空航天学院, 厦门 361005 |
| 基金项目： | 国家自然科学基金（51606161，91441128，11602209）；中央高校基本科研业务费专项资金（20720170055）；福建省软科学基金（2017R0099） |
| 摘 要： | 液态射流撞击是液体火箭推进系统中广泛采用的一种燃料雾化方法，其破碎特征直接影响燃料最终的掺混及燃烧效率。采用直接数值模拟（DNS）工具，研究了低雷诺数（Rel=41）和中等韦伯数（Wel=163）条件下剪切稀化非牛顿射流撞击液膜破碎的问题，着重分析了对角液膜的三维结构、破碎特征和非牛顿特性等。研究结果表明：在所研究的射流参数下，该非牛顿撞击液膜破碎属于Open Rim类别，破碎过程具有三维特性并伴随液丝与边缘的融合、液丝向液滴的转变等时域流动特征。液体的总表面积随时间不断增长，但单位表面积随液膜破碎的发生而下降，液膜扩张半角随时间逐渐增加并趋于恒定值43°，而后部液膜的长度几乎不随时间发生变化。此外，撞击液膜表现出明显的剪切稀化特性，液体内部最低黏性系数仅为零剪切黏性系数的1/5。 |
| 关 键 词： | 撞击射流 非牛顿流体 液膜破碎 直接数值模拟(DNS) 剪切稀化 |
| 收稿时间： | 2017-12-29 |
| 修稿时间： | 2018-03-26 |
Direct numerical simulation of sheet breakup formed by two impinging jets with non-Newtonian shear thinning properties |
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| ZHU Chengxiang,WU Meng,CHEN Rongqian,YOU Yancheng. Direct numerical simulation of sheet breakup formed by two impinging jets with non-Newtonian shear thinning properties[J]. Acta Aeronautica et Astronautica Sinica, 2018, 39(5): 121982-121982. DOI: 10.7527/S1000-6893.2018.21982 | |
| Authors: | ZHU Chengxiang WU Meng CHEN Rongqian YOU Yancheng |
| Affiliation: | School of Aerospace Engineering, Xiamen University, Xiamen 361005, China |
| Abstract: | Impinging liquid jets have been widely used in liquid rocket propulsion systems as a fuel atomization method. The breakup mechanism of impinging liquid jets directly affects the mixing and combustion efficiency of the fuel. In the present work, a Direct Numerical Simulation (DNS) tool is applied to study the sheet breakup formed by two impinging jets with non-Newtonian shear thinning properties under low Reynolds number (Rel=41) and moderate Weber number (Wel=163), including in particular the three-dimensional structure, breakup mechanism, and non-Newtonian feature of the diagonal liquid sheet. The results indicate that the breakup regime of the impinging sheet under current conditions belongs to the Open Rim type. Collison of ligament with rim as well as transition from ligament to droplet can be observed during the sheet breakup. The total liquid surface area increases with time, whereas the specific surface area decreases with the occurrence of sheet breakup. The half-expansion angle of the liquid sheet increases with time and eventually tends to be a constant 43°, but the length of the back sheet shows no tendency of change with time. Additionally, a strong shear thinning feature can be found within the liquid sheet, with the lowest viscosity of the liquid sheet being only 1/5 of that at zero shear rate. |
| Keywords: | impinging jets non-Newtonian fluid sheet breakup Direct Numerical Simulation (DNS) shear thinning |
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