基于表观BRDF的泡沫金属辐射特性反演测量方法

Inversion measurement method for radiative properties of foam metal based on apparent BRDF

泡沫金属是通过在金属基体上形成大量孔隙结构而得到的一类新型多功能材料,在太阳能利用、强化换热等领域有重要应用价值,其辐射特性参数是分析其内部辐射传递的必要物性数据。提出一种基于表观双向反射分布函数(BRDF)测量数据反演泡沫金属热辐射物性的方法,利用测量的多角度入射的表观BRDF数据结合辐射传递方程求解来反演泡沫金属的等效辐射特性。对泡沫铁镍(50 ppi)、泡沫铜(90 ppi)及泡沫镍(30 ppi)三种泡沫金属样品在波长660 nm激光照射下1/2半球空间的表观BRDF分布进行了实验测量,并对其辐射特性进行了反演,首次获得了这三种材料的辐射特性参数,其辐射物性表现出明显的半透明性质,散射反照率随着孔隙数密度的增加而增加,散射相函数呈后向散射占优。

Foam metal is a new kind of multi-functional materials produced by forming a large number of pores in metal substrate,which finds important applications in solar energy harvesting,enhanced heat transfer,etc,its radiative properties parameter are essential physical data for analysis on radiative transfer in metal foams. An inversion measurement method is presented to measure radiative properties of foam metal based on apparent bidirectional reflectance distribution function（ BRDF） data,radiative properties are inversely identified by using the measured BRDF data at multi incidence angles combined with numerical solution of radiative transfer equation. The apparent BRDF distribution of 1 /2 hemisphere space of three foam metal samples,namely,ironnickel foam（ 50 ppi）,copper foam（ 90 ppi） and nickel foam（ 30 ppi） are experimentally measured at laser wavelength 660 nm and analyzed,furthermore,their radiative properties are inversed. These foam metal show obvious semitransparent characteristics,scattering albedo increases with increase of pore density,scattering phase function show backward dominant characteristics.