Some effects of interface on fluid flow and heat transfer on micro- and nanoscale

Abstract

The interfacial effects on flow and heat transfer on micro/nano scale are discussed in this paper. Different from bulk cases where interfaces can be simply treated as a boundary, the interfacial effects are not limited to the interface on a microscale but could extend into a significant, even the whole domain of the flow and heat transfer field when the characteristic size of the domain is close to the mean free path (MFP) of the carriers inside an object. Most of microscale thermal phenomena result from interfacial interactions. Any changes in the interactions between the object and boundary particles, such as the force between fluid and solid wall particles, microstructure of interfaces, could affect thermal properties, flow and heat transfer characteristics and hence change thermal conductivity, velocity and temperature profiles, friction coefficient and thermal radiative properties, etc. The properties of nanostructure or flow and heat transfer features of fluid in micro/nanostructures not only depend on themselves, but also on the interaction with the interface because the interface impact can go deep inside the flow. The same fluid, same channel geometry but different wall materials could have different flow and heat transport characteristics on microscale.

An atomic level study on the out-of-plane thermal conductivity of polycrystalline argon nanofilm

“…Solid argon is selected as the simulation material for its simple potential function, and because its thermal conductivity is also widely simulated or measured by researchers [1][2][3][4][5]10]. As argon is an inert element and a dielectric material, we only consider the phonon transport that dominates the thermal conductivity, without considering the electrons or their interactions with phonons.…”

“…Molecular dynamics (MD) simulation has become a widely used method to investigate the thermal conductivity of single-crystal nanofilms during the last decade because of its low cost and high efficiency [1][2][3][4][5]. As an example, Lukes et al [1] studied the feasibility of using the MD computational technique to predict the normal thermal conductivity of solid argon thin films, and their result shows that the thermal conductivity increases with the atomic layer number.…”

Investigation of thermal rectification in bi-layer nanofilm by molecular dynamics

“…Due to the different lattices between two real crystal materials, it is hard to construct a solidesolid interface between two solid crystals with periodic boundary condition in molecular dynamics (MD) simulation. Liang [16] simply changed the atomic mass in different layers and investigated the thermal rectification in the normal conduction of a bi-layered nanofilm with solid argon structure by nonequilibrium molecular dynamics (NEMD) method. The average temperatures with opposite heat flux directions are different because of the constant heat flux used, which is possibly one of the causes of thermal rectification.…”

Size Effects on the Entropy Production in Oscillatory Flow between Parallel Plates

“…This situation will not be considered here in such a way that the velocity slip and the temperature jump at the boundaries are not included in the Navier-Stokes equations. Size effects have attracted the interest of both applied and theoretical researchers since several years ago [14][15][16][17][18][19][20][21]. In this paper we examine the size effects on the flow and heat transfer problem of a zero-mean oscillatory flow of a Maxwell fluid between infinite parallel plates with boundary conditions of the third kind.…”