Direct matching between the flow factor approach model and molecular dynamics simulation for nanochannel flows

Abstract

Mathematically formulating nanochannel flows is challenging. Here, the values of the characteristic parameters were extracted from molecular dynamics simulation (MDS), and directly input to the closed-form explicit flow factor approach model (FFAM) for nanochannel flows. By this way, the physical nature of the simulated system in FFAM is the same with that in MDS. Two nano slit channel heights respectively with two different liquid-channel wall interactions were addressed. The flow velocity profiles across the channel height respectively calculated from MDS and FFAM were compared. By introducing the equivalent value $${{\Delta_{im} } \mathord{\left/ {\vphantom {{\Delta_{im} } D}} \right. \kern-\nulldelimiterspace} D}$$ Δ im / D , FFAM fairly agrees with MDS for all the cases. The study values FFAM in simulating nanochannel flows.

Combined effects of surface roughness and physically adsorbed layer in hydrodynamic journal bearing with multiscale approach

“…The weak fluid‐bearing surface interaction gives the effective viscosity and average density of the adsorbed layer just a little bigger or even very close to the bulk viscosity and bulk density of the fluid [18]. It also results in the weak non‐continuum effect across the adsorbed layer thickness [18]. The medium interaction gives the significantly greater effective viscosity, average density and non‐continuum effect of the adsorbed layer [18, 21].…”

“…The above mentioned three types of the interaction are owing to the different interaction potential energies between the fluid and the bearing surface [18][19][20]. The weak fluid-bearing surface interaction gives the effective viscosity and average density of the adsorbed layer just a little bigger or even very close to the bulk viscosity and bulk density of the fluid [18]. It also results in the weak non-continuum effect across the adsorbed layer thickness [18].…”

“…It also results in the weak non-continuum effect across the adsorbed layer thickness [18]. The medium interaction gives the significantly greater effective viscosity, average density and non-continuum effect of the adsorbed layer [18,21]. While the strong interaction gives the much greater effective viscosity, average density and non-continuum effect of the adsorbed layer, even indicating the solidification of the adsorbed layer [20,21]…”