Three-Dimensional Numerical Simulation Of Gaseous Slip Flow In Rectangular Microtubes

With the development of MEMS and biological engineering technology, more and more attention has been paid to the problems of micro-scale flow and thermal transmission. The study of flow in micro-scale tubes has great importance to the application of MEMS and biological chips.To describe 3-D gaseous slip flow in rectangular microtubes, finite volume method with pressure correction scheme and velocity ahead uniform staggered grid is adopted. The dynamic parameters, including velocity,pressure,mass flow rate,Darcy friction factor, have been analyzed and compared with non-slip flow. Many results in the literatures have suggested that in the slip regime( 10 ?3≤Kn≤0.1), N-S equation with slip velocity and temperature jump boundary condition can be applied. Nitrogen flows have been studied in this paper. Numerical results indicate that, for the case of slip flow and Kn = 0.055,the velocity of slip flow in the microtubes is bigger than that of non-slip flow,and the velocity on the wall is no longer equal to zero; the pressure gradient of slip flow is smaller than that of non-slip flow,that is, the pressure gradient overcomes the friction on the wall and the slip boundary condition results in smaller friction. Moreover, the influence of rarefaction effect on mass flow rate and Darcy friction factor are also investigated. We find that rarefaction effect increases mass flow rate and decreases Darcy friction factor.Our results of the 3-D gaseous slip flow in rectangular microtubes are consistent with 2-D numerical and experimental results. Besides,it also shows 3-D effect and gives some suggestion the study of 3-D gaseous flow in microtubes.