ABSTRACT
Non-equilibrium molecular dynamics simulations of liquid flow through the surface were performed to investigate the flow resistance and thermal resistance under conditions of different solid-liquid interactions and surface temperatures. A novel phenomenon was observed in the simulation, namely the rise of surface temperature increases the flow resistance when solid-liquid interaction is weak, but decreases the flow resistance when solid-liquid interaction is strong. A higher density of the boundary layer brings a larger friction force to increase the flow resistance. For heat transfer, it is innovative to calculate the heat conduction and convection of the boundary region discretely. The results showed that the heat transfer performance of the interface is not positively correlated with the boundary liquid density, and the structure of the boundary liquid is also crucial. We believe that this research can improve the existing theory of flow heat transfer and provide a more effective method for analyzing the flow heat transfer of the solid-liquid interface.
ABSTRACT
In this paper, a 2D periodic structure made of tungsten (W) grating patch on a thin Al2O3 spacer and an opaque W film is proposed, as a broadband selective thermal emitter. We numerically investigated the spectral emissivity of the structure from the deep by finite-difference time-domain method. Geometric parameters effects on the emissivity are discussed and the mechanisms of magnetic polaritons in the structure are further analyzed in detail. In addition, by adding another metal-dielectric stack upon the pre-existing grating structure, the emissivity of the composite structure can be further enhanced, and the normal emissivity exceeds 0.95 in the wavelength range of 0.65-1.95 µm, some even close to unity. Furthermore, the composite structures are found to exhibit insensitivity to polar angle and polarization.
