سال انتشار: ۱۳۸۷

محل انتشار: دومین کنگره بین المللی علوم و فناوری نانو

تعداد صفحات: ۳

نویسنده(ها):

s Vakilipour – Department of Aerospace Engineering, Sharif University of Technology. P.O. Box 11365-8639. Tehran
m Darbandi –

چکیده:

The fast progress in nano-systems has drawn the attention of many numerical workers to provide suitable numerical tools to analyze nanoflows more accurately. The rarefaction effect on the mass transfer is an important phenomenon in gas flows through nanoscale channels. Essentially, the experimental measurements are the most reliable way to find mass flow rate of the nano gaseous flows. Arkilic et al. [1] performed high-precision mass flow rate measurements to obtain the tangential momentum accommodation coefficient (TMAC) of nitrogen, argon and carbon dioxide flows in long micro and nanoscale channels for the outlet Knudsen numbers up to 0.44. They showed that the TMAC would decrease as the flow reaches to the transition condition. Maurer et al. [2] conducted some experiments to find second order slip coefficient using nitrogen and helium flow rate measurements in high aspect ratio nanochannels with the outlet Knudsen number ranging from 0.054 to 1.46. They concluded that the second order effects become significant beyond the Knudsen number of the slip flow limit. Ewart et al. [3] carried out experimental investigations to measure the mass flow rate in isothermal flows through nanotubes. They obtained a way for calculating the mass flow rate comparing the measured values with the analytical solutions of continuum equations. Colin et al. [4] proposed an analytical second-order slip-flow model performing measurements of gaseous micro to nanoflow rates under controlled temperature and pressure conditions. The mass flow rate calculated by their model is correct for Knudsen numbers up to about 0.25 where the first order model is no longer accurate, while, the obtained velocity profiles is no longer valid for Kn>0.1