Investigating the effect of wall temperature on the thermal performance of NH3 in the presence of suspended roughness in the 2D and 3D nanochannels: A molecular dynamics study

Abstract

In thermal channels, the heat transfer coefficient increases by variations the fluid conditions, boundary conditions, or wall temperature. This article investigated the ammonia fluid manner with suspended roughness, in a nanochannel via molecular dynamics (MD) approach and LAMMPS open-source software. The change in thermal conductivity and heat flux were investigated to investigate the nanostructure's thermal behaviour. And its atomic behaviour in the nanochannel was investigated by examining the density and velocity profiles. In this study, two 2D and 3D copper nanochannels have been used. At first step, the equilibrium in the simulated structure was checked by examining the kinetic energy and potential changes. The results show that the peak point of fluid density in the areas near the wall of the nanochannel is higher than the middle areas in the nanochannel. This is because the intermolecular interaction is greater in the fluid molecules near the wall and eventually becomes smaller and more uniform in the middle regions of the fluid. Also, the results show that 2D and 3D nanochannel thermal conductivity converges to a numerical value of 0.53143 and 0.6063 W/mK after 10 ns. By changing the nanochannel wall's temperature, the motion of the particles in the channel increases. So the thermal conductivity in 2D and 3D nanochannel increase to 0.7176 and 0.7677 W/mK. The results will be effective in improving the performance of heating systems.