In this paper Couette flow at micro/nano scale is considered, simulated and analyzed with a special focus on two quantities, namely entropy and entropy generation rate, in the framework of the entropy transport equation using the direct simulation Monte Carlo (DSMC) method.We compared microscopic solution of entropy with its corresponding solution from the classical thermodynamics. To investigate the entropy generation behavior 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.It is identified that the combined model provides more realistic results compared to other two models.Moreover, entropy generation follows the density profiles while entropy shows similar trends to the temperature profiles. Finally, physical links between the terms in the entropy transport equation are discussed.

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