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(181f) A Molecular Dynamics Simulation Study of the Kapitza Heat Transfer Resistance

Stephan, S., Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern
Hasse, H., University of Kaiserslautern
The heat transfer across a solid-fluid interface was systematically investigated by molecular dynamics simulations of a model system [1]. The studied system consists of a fluid confined between two parallel planar walls. There is no convection. Both the fluid and the solid were modeled with the Lennard-Jones truncated and shifted potential. The following parameters were varied systematically: channel height, temperatures of the wall and the fluid, density of the fluid, strength of the solid-fluid and the solid-solid interaction, and the mass of the solid particles. From the simulation results, numbers for the Kapitza length LK were obtained, which characterizes the heat transfer resistance at the solid-fluid interface. A correlation of the results for the Kapitza length LK as a function of the studied variables was developed. Moreover, a dimensionless number is introduced, the Kapitza interface number Ki, that describes the Kapitza effect in the stagnant fluid and is zero in the absence of the Kapitza effect. It is discussed, how the results from the present work can be used to assess the influence of the Kapitza effect in practical applications and how they can be applied to cases in which convection plays a role.

[1] S. Schmitt, T. Vo, M.P. Lautenschlaeger, S. Stephan, H. Hasse, Mol. Phys. (2022), in press.