高孔隙率通孔金属泡沫有效导热系数的实验和理论研究  

Experimental and Analytic Investigations for Effective Thermal Conductivity in High Porosity Metallic Foams

作　　者：杨肖虎[1] 邝九杰[1] 白佳希 卢天健[2] 金东范 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049 [2]西安交通大学机械结构强度与振动国家重点实验室,西安710049 [3]金山大学机械工程学院

出　　处：《西安交通大学学报》2014年第4期79-84,共6页Journal of Xi'an Jiaotong University

基　　金：国家重点基础研究发展规划资助项目(2011CB6103005);高等学校学科创新引智计划资助项目(B06024);国家自然科学基金资助项目(51206128)

摘　　要：为了研究高孔隙率通孔金属泡沫中的热传导特性及预测有效导热系数,发展了一种新的全解析有效导热系数模型。该模型通过建立更真实的十四面体三维结构作为代表单元,解析求解代表单元内稳态傅里叶热传导方程获得通孔泡沫铝的有效导热系数。该模型不含任何拟合或经验参数,有效导热系数与孔隙率之间具有简单的线性关系,且比例系数阐释了热曲折率的大小。高孔隙率下,模型预测与实验测量和文献数据吻合良好。研究结果表明:对于具有大导热系数比的实心杆与流体相(如充满空气的泡沫铝),流体相的传热可忽略不计,热量沿着曲折金属杆的一维传导占主导地位。在忽略自然对流和辐射传热时,泡沫铝有效导热系数基本不受孔密度及杆截面形状的影响。在所研究的温度范围内,泡沫铝有效导热系数可视为常数。To demonstrate a totally analytic model of effective thermal conductivity in high porosity open-cell metallic foams, a 3D tetrakaidecahedron configuration is selected as the representative unit cell for the metal foam. By solving 1D steady-state Fourier＇s equation for the representative volume, a purely analytic model without requiring any fitting or empirical coefficient is obtained. Coinciding well with the present measurements and experimental data from literature, this model suggests a linear dependence of effective thermal conductivity upon porosity, where the proportionality coefficient is the reciprocal of thermal tortuosity. The heat transfer in fluid phase is negligible due to large thermal conductivity ratio between solid ligaments and fluid phase （e. g. , air-saturating A1 foam）, 1D heat conduction along the tortuous ligaments thus dominates. Neglecting natural convection and radiation of thermal energy, the topological parameters, such as pore density （PPI） and ligament cross-sectional shape, exert little influenceon effective thermal conductivity. Furthermore, the effective conductivity remains constant within the experimental temperature range.

关 键 词：有效导热系数 通孔金属泡沫 一维热传导 十四面体 

分 类 号：TK311[动力工程及工程热物理—热能工程]