Macroscopic description of nonequilibrium effects in thermal transpiration flows in annular microchannels.
نویسندگان
چکیده
Thermal transpiration flow of rarefied gases in annular channels is considered where the driving force for the flow is a temperature gradient applied in the channel walls. The influence of gas rarefaction, aspect ratio of the annulus, and surface accommodation coefficient on mass and heat transfer in the process are investigated. An analytical approach to the problem is conducted based on linearized Navier-Stokes-Fourier (NSF) and regularized 13-moment (R13) equations, and a closed-form expression for Knudsen boundary layers is obtained. The results are compared to available solutions of the Boltzmann equation to highlight the advantages of the R13 over the NSF equations in describing nonequilibrium effects in this particular thermally driven flow. Through comparisons with kinetic data, it is shown that R13 equations are valid for moderate Knudsen numbers, i.e., Kn<0.5 where NSF equations fail to describe the flow fields properly.
منابع مشابه
Thermal Transpiration Flow in Annular Microchannels
Thermal transpiration flows of rarefied gases in annular channels are considered, where the driving force for the flow is a temperature gradient applied in the channel walls. The influence of gas rarefaction, aspect ratio of the annulus, and surface accommodation coefficient on mass and heat transfer in the process are investigated. For this, the linearized Navier– Stokes–Fourier (NSF) and regu...
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ورودعنوان ژورنال:
- Physical review. E, Statistical, nonlinear, and soft matter physics
دوره 86 3 Pt 2 شماره
صفحات -
تاریخ انتشار 2012