Extended Thermodynamic Approach for Non-Equilibrium Gas Flow

Publisher: Cambridge University Press

E-ISSN: 1991-7120|13|5|1330-1356

ISSN: 1815-2406

Source: Communications in Computational Physics, Vol.13, Iss.5, 2013-05, pp. : 1330-1356

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Abstract

Gases in microfluidic structures or devices are often in a non-equilibrium state. The conventional thermodynamic models for fluids and heat transfer break down and the Navier-Stokes-Fourier equations are no longer accurate or valid. In this paper, the extended thermodynamic approach is employed to study the rarefied gas flow in microstructures, including the heat transfer between a parallel channel andpressure-driven Poiseuille flows through a parallel microchannel andcircular microtube. The gas flow characteristics are studied and it is shown that the heat transfer in the non-equilibrium state no longer obeys the Fourier gradient transport law. In addition, the bimodal distribution of streamwise and spanwise velocity and temperature through a long circular microtube is captured for the first time.