Experimental and Numerical Study on Pore-Scale Spectral Radiative Properties of Ni Foam

The experiment involves normal-hemisphere reflectance/transmittance from foam slices with different thickness at incident wavelength of 0.4-2.2 μm. The pore-scale radiative transfer simulation is modeled with Monte Carlo method applied in foam reconstruction from computed tomography. The radiative properties of Ni foam obtained from experiment and simulation are compared and the pore-scale distributions of radiative properties are analyzed. The results show that the pore-scale radiative transfer model is valid to simulate the radiative properties of Ni foam. The absorptance decreases and reflectance increases as the incident wavelength becomes longer. With samples thick enough, the absorptance increases to a stable value, while the transmittance decreases to zero. In addition, the pore-scale distributions of radiative properties are strongly dependent on the local structure. With incident wavelength of 1.5 μm, the absorptance in void pores is 1.5 times of that on solid skeletons. However, the reflectance on solid skeletons is 3.7 times of that in void pores.