Analysis on near field radiative heat transfer for surface morphology of semitransparent particles

In this work, random surface morphology of particles have been built to discuss the morphology's influence on near-field radiation. The method which combines Finite Difference Time Domain (FDTD) and disperse dipole approximation (DDA) is proposed to simulate the radiative heat flux between particles. This method has been verified with the Temperature-DDA method's results, so it can be applied in other appropriate cases. The paper uses random Gaussian distribution to constructed the rough surface and calculates radiative conductance in several deviation with different conditions such as particle shapes, material spectral properties and rotation. As results, it shows that the low deviation σ₁ = r/50 (r is radius of sphere particle) has smaller influence in short spectral. When σ₃ = r/10, radiative conductance reduce 10% ~ 35% in the 1–10 µm sizably, and this is caused by the particles’ irregular surface. After changing other conditions, the deviation's influence almost keeps same standard, and the maximum radiative conductance deviation always occur in long wavelength. This work uses the real material's properties to discuss silica particles’ radiative heat transfer, which shows that the surface morphology's influence is finite, because radiative conductance peak also happen at about 8.5 µm wavelength.