Molecular dynamics study on the effect of external electric field on thermal properties of ammonia/copper nano-refrigerant in a nanochannel equipped with different types of cavities

Abstract

Optimizing and increasing the efficiency of heat transfer systems was one of the main challenges for engineers and designers in recent years. Therefore, the use of nanoparticles in base fluids is known as a passive method to improve heat transfer and shrink heating and cooling systems. In this research, the heat transfer of copper nanoparticles with ammonia refrigerant in a nanochannel was investigated by molecular dynamics simulation. The results show that, with increasing the electric field frequency from 0.1 1/ps to 0.5 1/ps, the phase change time increases from 2 ns to 3 ns and the thermal conductivity decreases from 0.76 W/m.K to 0.72 W/m.K. Also, the effect of the different cavities (hermetic, spherical, and cube shape) in the nanochannel on the atomic and thermal behavior of the simulated atomic samples is investigated. The results show that the maximum thermal conductivity of the sample with a cubic cavity is 0.80 W/m.K. The particle phase change value and the phase change time of samples with hermitic, spherical, and cube atomic cavities are obtained 65, 66, and 68%, and 2.88, 2.87, and 2.85 ns, respectively.