Developing consistent inlet boundary conditions to study the entrance zone in microchannels

作者：Darbandi Masoud^*; Vakilipour Shidvash

来源：Journal of Thermophysics and Heat Transfer, 2007, 21(3): 596-607.

DOI：10.2514/1.27509

One important point in microflow study is the correct consideration of the Knudsen layer. In addition to the many complexities behind numerical simulation of the Knudsen layer near the solid walls, there are serious uncertainties at the microchannel inlet (the point at which the flow enters the microdomain). One major difficulty is the appearance of two singularities at the two corners of the inlet section. They seriously affect the solution in the entrance region of microchannels in which the lengths are comparable with the lengths of their hydrodynamic developing zones. Although the macro inlet flow problem has been largely investigated, there has been little attempt to study the issue in microdomains. In this research, we use our experience in solving macro entry-flow problems and extend it suitably to microflow applications. To avoid the singularities and to achieve more realistic conditions at the real inlet, we implement suitable boundary conditions far upstream of the channel. This strategy reduces the erroneous role of the singularities and permits a more accurate solution in the entrance region of the microchannel. This paper deals with the numerical solution of the entrance region in short-length microchannels in which the compressibility effect is minor.

• 出版日期2007-9