Free-molecule heat transfer in a conservative force field between parallel surfaces.
The heat flux between parallel surfaces is computed analytically assuming that heat is transferred by particles moving ballistically under the influence of a conservative force field. Particle reflection at the surfaces is governed by a Maxwell-type boundary condition. It is found that the force field can give rise to a substantial reduction, but also to an enhancement of the heat flux, depending on the ratio of the temperatures at the two surfaces. The influence of the accommodation coefficients is studied. An asymmetry introduced by the force field and/or the boundary conditions at the two surfaces causes a significant heat-flux rectification, characteristic for a thermal diode.
Institute for Nano- and Microfluidics, Center of Smart Interfaces, Technische Universität Darmstadt, Germany.
Steffen
S
Hardt