Adiabatic piston in a temperature gradient

TL;DR

This paper investigates the steady states of two gases separated by an adiabatic piston under a temperature gradient, using kinetic theory and molecular dynamics simulations to analyze hydrodynamic effects and entropy production.

Contribution

It introduces a simple kinetic theory model for the system and compares its predictions with molecular dynamics simulations, highlighting the model's accuracy and limitations.

Findings

Kinetic theory predictions agree well with simulations.

The piston causes significant hydrodynamic field jumps.

Minimum entropy production principle is valid only for small temperature gradients.

Abstract

The steady states of two gases of hard spheres or disks separated by an adiabatic piston in presence of a temperature gradient are discussed. The temperature field is generated by two thermal walls at different temperatures, each of them in contact with one of the gases. The presence of the piston strongly affects the hydrodynamic fields, inducing a jump in its vicinity. A simple kinetic theory model is formulated. Its predictions are shown to be in good agreement with molecular dynamics simulation results. The applicability of the minimum entropy production principle is analyzed, and it is found that it only provides an accurate description of the system in the limit of a small temperature gradient.