Open-cell foams consisting of interconnected struts are widely used in thermal applications such as volumetric solar receivers. The thermal performance of foams strongly relies on their radiative behaviors which intrinsically depends on the radiative properties of struts. This study proposed a feasible approach to determine the radiative properties of solid struts by a pore scale identification from a macro scale measurement. First, the normal-hemispherical transmittance and reflectance spectra of two nickel foams were measured by an experimental system. Second, a pore scale forward calculation was conducted by a combination of Monte Carlo Ray-tracing method and real foam structures obtained from micro-computed tomography technique. Last, an Adaptive Particle Swarm Optimization algorithm was adopted to retrieve the spectral reflectivity and specularity of nickel struts from the measured spectra. The results show that it is unreasonable to assume the reflection behavior of strut surface simply as either specular or diffused, and also, it is unreliable to assign the reflectivity of strut surface directly by Fresnel's law. Within the investigated wavebands 0.4–2.2 μm, the average reflectivity of nickel struts is 12% lower than that of a nickel mirror. The proportion of specular reflection at nickel strut surface is between 37%–52%, almost increasing with wavelengths.

由相互连接的支柱组成的开孔泡沫广泛用于热应用中，例如体积太阳能接收器。泡沫的热性能很大程度上取决于其辐射性能，而辐射性能本质上取决于支柱的辐射性能。这项研究提出了一种可行的方法，可通过从宏观测量结果中进行的孔尺度识别来确定固体支柱的辐射特性。首先，通过实验系统测量了两种镍泡沫的法向半球透射率和反射率光谱。其次，结合蒙特卡罗射线追踪法和由微计算机断层摄影技术获得的真实泡沫结构，进行了孔隙尺度的正演计算。最后的，采用自适应粒子群优化算法从测得的光谱中检索镍撑杆的光谱反射率和镜面反射率。结果表明，单纯以镜面反射或漫射来假设支撑杆表面的反射行为是不合理的，并且直接根据菲涅耳定律来指定支撑杆表面的反射率是不可靠的。在研究的0.4-2.2μm波段内，镍撑杆的平均反射率比镍镜的平均反射率低12％。镍支杆表面的镜面反射比例在37％–52％之间，几乎随波长而增加。根据菲涅耳定律直接指定支撑杆表面的反射率是不可靠的。在研究的0.4-2.2μm波段内，镍撑杆的平均反射率比镍镜的平均反射率低12％。镍支杆表面的镜面反射比例在37％–52％之间，几乎随波长而增加。根据菲涅耳定律直接指定支撑杆表面的反射率是不可靠的。在研究的0.4-2.2μm波段内，镍撑杆的平均反射率比镍镜的平均反射率低12％。镍支杆表面的镜面反射比例在37％–52％之间，几乎随波长而增加。