摘要
【目的】为了系统研究开孔金属泡沫中空气流场的流动特性和传热传质特性。【方法】使用几何表示法构建12面体开孔泡沫模型,应用有限单元法模拟了不同入口速度下,泡沫韧带截面形状、孔径密度PPI和流场高度方向泡沫结构对称性等参数对流场分布、传质和流动阻力的影响。【结果】结果表明,随着泡沫韧带截面顶点曲率减小,韧带阻滞作用减弱,流场沿程损失h_(f)减少;增大孔径密度可以提高流场对流强度分布均匀性;在高度方向非对称边界流场对流强度更大,且韧带周围对流强度分布趋向均匀,对称结构则相反;对称边界流场的上下边界处对流速度比非对称边界略大,对称边界更有利于边界物质输运;泡沫结构特征和气体入口速度对流场分布和流动阻力的影响明显。流动问题的量纲分析结果表明,泡沫孔数量越多,流场的沿程损失与气体初始动能的比值越大,增大气体入口速度则比值减少,当入口速度超过6 m/s后,比值趋于稳定。
【Purposes】 This research is carried out in order to systematically study the flow characteristics, heat and mass transfer characteristics of air flow field of open-cell metal foam. 【Methods】 The dodecahedron as a single cell of metal foam model is constructed by geometric representation. The influences of parameters of the cross-section shape of foam ligament, pore density(PPI), and the symmetry of foam structure in the direction of flow field at altitude on flow field distribution, mass transfer, and flow resistance at different inlet velocities are simulated by finite element method. 【Findings】 The results show that with the decrease of the vertex curvature of the foam ligament cross-section, the blocking of ligaments is weakened, and the friction loss(h_(f)) of flow field decreases. Increasing the pore density can improve the distribution uniformity of convective intensity in flow field. In the height direction, the convection intensity of the asymmetric boundary field is greater, and the distribution of the convection intensity around ligaments tends to be uniform, while that of the symmetric structure is opposite. The convection velocities at the upper and lower boundaries of the symmetric boundary are slightly larger than those at the asymmetric boundary structure, and the symmetric structure is more conducive to mass transport at boundaries. The characteristics of open-cell metal foam structure and gas inlet velocity have obvious influences on the flow field distribution and flow resistance. The dimensional analysis results of the flow problem show that the more the number of pores, the greater the ratio of friction loss of flow field to the initial kinetic energy of the gas, and the ratio is reduced as the inlet velocity increasing. When the inlet velocity is greater than 6 m/s, the ratio tends to be stable.
作者
郑紫君
王根伟
宋辉
韩鹏飞
ZHENG Zijun;WANG Genwei;SONG Hui;HAN Pengfei(College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,Chin;College of Aeronautics and Astronautics,Taiyuan University of Technology,Taiyuan 030024,Chin;Shanri Key Lab.of Material Strength&Structural Impact,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《太原理工大学学报》
CAS
北大核心
2024年第4期581-590,共10页
Journal of Taiyuan University of Technology
基金
山西省关键核心技术和共性技术研发攻关专项(2020000017)。
关键词
开孔金属泡沫
韧带截面形状
泡沫结构对称性
孔径密度
沿程损失
传质能力
open-cell metal foam
ligament cross-section
symmetry of foam structure
pore size density
friction loss
mass transfer
