Related Experiment Video
Updated: Aug 24, 2025

Characterization of Thermal Transport in One-dimensional Solid Materials
Published on: January 26, 2014
Boundary conditions for the Boltzmann equation from gas-surface interaction kinetic models
Kazuo Aoki1, Vincent Giovangigli2, Shingo Kosuge3
1Department of Mathematics, National Cheng Kung University, Tainan 70101, Taiwan.
Abstract:
Boundary conditions for the Boltzmann equation are investigated on the basis of a kinetic model for gas-surface interactions. The model takes into account gas and physisorbed molecules interacting with a surface potential and colliding with phonons. The potential field is generated by fixed crystal molecules, and the interaction with phonons represents the fluctuating part of the surface. The interaction layer is assumed to be thinner than the mean free path of the gas and physisorbed molecules, and the phonons are assumed to be at equilibrium. The asymptotic kinetic equation for the inner physisorbate layer is derived and used to investigate gas distribution boundary conditions. To be more specific, a model of the boundary condition for the Boltzmann equation is derived on the basis of an approximate iterative solution of the kinetic equation for the physisorbate layer, and the quality of the model is assessed by detailed numerical simulations, which also clarify the behavior of the molecules in the layer.
Related Concept Videos
Maxwell-Boltzmann Distribution: Problem Solving
This distribution function f(v) is defined by saying that the expected number N (v1,v2) of particles with speeds between v1 and v2 is given by
Distribution of Molecular Speeds
Van der Waals Equation
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision
Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation
Kinetic Molecular Theory: Molecular Velocities, Temperature, and Kinetic Energy

