Compressibility and rarefaction effects on entropy and entropy generation in micro/nano Couette flow using DSMC

Abstract

Abstract. In the present work, compressible flow of argon gas in the famous problem of Couette flow in micro/nano-scale is considered and numerically analyzed using the direct simulation Monte Carlo (DSMC) method. The effects of compressibility and rarefaction on entropy and entropy generation in terms of viscous dissipation and thermal diffusion are studied in a wide range of Mach and Knudsen numbers and the observed physics are discussed. In this regard, we computed entropy by using its kinetic theory formulation in a microscopic way while the entropy generation distribution is achieved by applying a semi-microscopic approach and thoroughly free from equilibrium assumptions. The results of our simulations demonstrated that the entropy profiles are in accordance with the temperature profiles. It is also illustrated that the increase of Mach number will result in non-uniform entropy profiles with increase in the vicinity of the central regions of the channel. Moreover, generation of entropy in all regions of the domain stages clear growth. By contrast, increasing the Knudsen number has inverse effects such as: uniform entropy profiles and a falling off in entropy generation amount throughout the channel.

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

“…The influence of relevant parameters on the local Nusselt number distribution is shown in Figure 5 . Ejtehadi [ 64 ] analyzed the influence of compressibility and rarefaction on micro/nanoscale Couette flow from the perspective of entropy generation. Research showed that the increase of Mach number leads to non-uniform entropy profiles near the central region of the channel.…”

Surface Roughness of Electrospun Nanofibrous Mats by a Novel Image Processing Technique

“…Measuring the roughness of nano¯brous structures by AFM has been suggested by some researchers. [10][11][12][13][14][15][16][17][18] Baltsavias compared two di®erent approaches of roughness measurement. The results show that the indirect method is more practical and useful for calculation of standard surface pro¯le measurement, compared with the stylus pro¯lometer for characterization of a surface topography.…”

Transient Velocity And Steady State Entropy Generation In A Microfluidic Couette Flow Containing Charged Nano Particles

“…The open literature shows a very small number of papers that deal with entropy generation related problems in the field of microfluidics. Ejtehadi et al (2012) numerically analyzed compressibility and rarefaction effects on entropy generation in a micro/nano Couette flow using the direct simulation Monte Carlo (DSMC) method. Under more general conditions Ibanez and Cuevas (2010) analyzed, the thermal behavior of viscous fluid flow in a parallel wall microchannel subjected to electromagnetic interaction.…”