Molecular dynamics simulation on the microstructure of absorption layer at the liquid–solid interface in nanofluids ☆

Abstract The microstructure of absorption layer at the liquid–solid interface in nanofluids is investigated by molecular dynamics simulation, with consideration of various influential factors including: nanoparticle shape, nanoparticle size, and nanoparticle material. By analyzing number density distribution, radial distribution function, and potentials of mean force the microscopic mechanism in absorption layer is depicted. It is found that the microstructure of absorption layer due to the adding of nanoparticles is entirely different from that of single-phase base fluid. The absorption layer has two denser locations of liquid atoms. The microscopic structure of absorption layer is more ordered and is close to that of solid material. A large energy barrier with a different cis–trans direction of energy barrier is found in potentials of mean force which reveals the mechanism of absorption layer formation. Furthermore, through calculating the mean square displacement and self-diffusion coefficient, the microscopic behavior of liquid atoms is connected to the macroscopic thermal conduction of nanofluids.