摘要
泡沫金属是一类新型功能材料,特殊的多孔结构使其具备多种优良性能。泡沫金属的孔隙及支架尺寸根据不同的准备工艺可以达到微米至亚微米尺寸.对于具有微米尺寸孔隙结构的泡沫金属,其内部热辐射传输的分析需要考虑热辐射的波动相干效应.本文使用时域有限差分法(FDTD)研究了入射波长与孔径尺寸相当时单层及多层周期性立方体元胞泡沫铝的光谱等效衰减系数,分析了层数不同引起的等效衰减系数的尺寸效应。结果表明,等效衰减系数随层数的增加存在一个复杂的非线性关系,尺寸效应引起单层结构等效衰减系数与多层结构(20层)等效衰减系数的偏差达到约20%,但采用2层结构与多层结构(20层)等效衰减系数的偏差小于6%,随着层数的增加获得的等效衰减系数趋于稳定。FDTD计算所得的透过率的结果与经典多层介质的净辐射热量法获得的不同厚度泡沫铝的透过率预测结果吻合较好,说明将泡沫铝等效为半透明介质再利用经典辐射传递理论进行辐射换热的分析是可行的。
Metal foam is a new functional material having a variety of excellent performances because of its special porous structure. The size of the porosity and stent can achieve micron and submicron depending on the preparation process. For the micron-sized pore, its internal analysis of the thermal radiation transfer needs to consider the coherence effect. This article uses the finite-difference time-domain （FDTD） method to study the spectra equivalent attenuation of the monolayer and multilayer periodic cube cells of aluminum foam and analyze the size effect when the incident wavelength is comparable with the pore size. The results show that there was a complex nonlinear relationship between the equivalent attenuation coefficient and the number of layers and the equivalent attenuation coefficient of monolayer structure reaches approximately 20% of the deviation with that of the multilayer structure （20 layers） due to the size effect, however, the deviation was less than 6% between the two-layer structure and the multilayer structure （20 layers）, and the effective spectral extinction coefficient stabilizes as the number of layers increases. The transmittance of aluminum foam with different thickness calculated by FDTD was in good agreement with the classical multilayer net radiation method which indicated that the method in which aluminum foam was equivalent to semitransparent media using the classical theory of radiative transfer was feasible.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2013年第10期1899-1901,共3页
Journal of Engineering Thermophysics
基金
国家自然科学基金(No.50906017
No.50836002)
哈尔滨工业大学优秀青年教师培养计划项目(No.HITQNJS.2009.020)
关键词
微尺度泡沫金属
多层结构
FDTD
净辐射热量法
光谱等效衰减系数
microscale metal foam
multilayer structure
FDTD
net radiation method
effectivespectral extinction coefficient
