Effects of various temperature and pressure initial conditions to predict the thermal conductivity and phase alteration duration of water based carbon hybrid nanofluids via MD approach

Abstract

Due to the presence of fluid flow inside channels in many natural and artificial systems and their widespread applications in recent years, attention to the issue of improving heat transfer is growing at an increasing rate. On the other hand, poor fluid heat transfer properties like water are a major obstacle to increasing heat transfer and making heat exchangers more efficient. At present work, hydrodynamic and thermal performances of liquid water in the attendance of two carbon structures (nanosheets of graphene and nanotubes of carbon) were examined by molecular dynamics simulation (MDS). At first, the atomic behavior of hybrid nanofluids was investigated by velocity and density profiles. Then, by studing the coefficient of conductivity (k) and duration of phase alteration in different initial conditions (different initial temperatures (t) and pressures (p)), the hydrodynamic and thermal performances of this mixture were presented. The results revealed with increasing initial t, the thermal conductivity and phase change duration changed from 0.68 W/m.K and 1.29 ns to 0.80 W/m.K and 1.05 ns. This change was due to the increase in the oscillation amplitude and the mobility of the particles in the box of simulation. Moreover, With increasing pressure in the structures, the amount of oscillation amplitude and the mobility of atomic structures decreased.