Keywords: DSMC, direct simulation, Monte Carlo simulation, micro/, nano–Couette flow, entropy transport equations, entropy generation, Knudsen layer, continuum breakdown, nanotechnology, nanodevices
Second law analysis of micro/nano Couette flow using direct simulation Monte Carlo method
In this paper, micro–/nano–Couette flow is considered with a special focus on entropy and entropy generation rate in the framework of the entropy transport equation using direct simulation Monte Carlo (DSMC) method. To investigate the entropy generation behaviour, three different models, i.e., equilibrium thermodynamics–base (ETB), non–equilibrium thermodynamics–base (NETB) and a proposed 'combined model', are applied and the ranges of validity of the employed models are discussed. Effects of compressibility and rarefaction on entropy and entropy generation behaviours are investigated. We also suggest 'specific entropy generation' as a tool for detecting non–equilibrium regions including Knudsen layer.