A qualitative analysis is first carried out to determine the slip coefficie
nt as a function of two dimensionless parameters. An intensive computation
using the direct simulation Monte Carlo method is then carried out to simul
ate the Couette flows between two walls for different gas, number density,
wall (plate) velocity (U-w), wall temperature (T-w) and distance between th
e two walls. Numerical results show that the slip coefficient is proportion
al to the mean free path lambda(gw) of molecules colliding with the wall, w
hich is affected by the number density, the wall temperature and gas mass.
The slip coefficient is finally found to be 1.125 lambda(gw). This slip coe
fficient is verified for five gases, and validated under the conditions of
U-w less than or equal to 300 m s(-1) and T-w less than or equal to 500 K.
This slip coefficient is very useful for slip flow analysis in micro-electr
o-mechanical systems using N-S equations.