Study for the particle's scale effect on some thermophysical properties of nanofluids by a simplified molecular dynamics method

For a stationary nanofluids of the volume fractions (α) less than 8%, a simplified molecular dynamics (MD) simulation method is constructed and used to simulate the thermophysical properties of nanofluids: thermal conductivity and viscosity. The better agreement between present numerical results and experimental data is presented in this paper. It shows the simplified dynamics simulation method to be an effective method to forecast some thermal properties of nanofluids. Many former experiments have shown that this new heat transfer fluids–nanofluids can greatly enhance the heat-transfer efficiency. This work further gives the effects of the volume fraction and the size of nanoparticles on the thermal conductivity and the viscosity of nanofluids. Numerical results show that, decreasing size of nanoparticle or increasing the volume fraction can increase thermal conductivity with increasing viscosity; for suitable volume fraction and size, increasing viscosity with improving heat transfer capability is acceptable.