Simulation of hard-disk flow in microchannels.
The dynamic flow behavior of a hard-disk fluid under external force field in two-dimensional microchannels is investigated using an event-driven molecular dynamics simulation method. Simulations have been carried out under laminar and subsonic conditions in both slip regime and transition regime, and the effects of three main factors, Knudsen number (Kn), force field intensity, and packing fraction, on flow and heat transfer behavior have been studied. It is shown that all the factors play important roles in the velocity distribution of the flow, and the temperature profile of the gas flow may exhibit a bimodal shape with a local minimum instead of a maximum in the center. These findings verify the predictions of nonequilibrium kinetic theories on the so-called "temperature dip." At high Kn, the two maxima of temperature shift to two walls and the temperature profile changes to a "parabola" opening upward with a minimum in the center. A slight setback of the temperature is also found before the fluid flow eventually arrives at a steady state when the shear rate is high enough.
Shen
Guofei
G
State Key Laboratory of Multi-phase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Ge
Wei
W