Rarefaction effect

Kn = 0.01-0.1 Slip flow rarefaction effects that can be modeled with a modified continuum theory with wall slip taken into consideration... 

Historically, gas lubrication theory was developed from the classical liquid lubrication equation—Re5molds equation [4]. The first gas lubrication equation was derived by Harrison [5] in 1913, taking the compressibility of gases into account. Because the classical gas lubrication equation is based on the Navier-Stokes equation, it does not incorporate some gas flow characteristics rooted in the rarefaction effects of dilute gases. As early as 1959, Brunner s experiment [6] showed that the classical gas lubrication equation was... 

To evaluate the intensity of the rarefaction effect, the him thickness h itself is not enough. We have to know the Knudsen number Kn or the inverse Knudsen number D. From the dehnition of Kn, Eq (2), and the relationship between and pressure, ... 

Table 5 gives the comparisons of the calculated load carrying capacity F, the pitch moment M (moment around Y axis), the maximum and minimum dimensionless pressures Pmax. Pmin the Speed of 9.57557 m/s, with and without consideration of the rarefaction effect. All of the absolute values of F, M, min become lower when the rar-... 

TABLE 5—Comparison of calculation results with and without rarefaction effect. ... 

Hsia, Y. T. and Domoto, G. A., An Experimental Investigation of Molecular Rarefaction Effects in Gas Lubricated Bearings... 

Detonation (and Explosion), Rarefaction Effect in Air Blast. See Vol 2, p B180-R... 

As indicated in Fig 2, curve (a) is useful in correlating experimental data, curve (b) is essentially a stress-strain curve, although it has other interesting features which will be discussed later, and curve (c) is most useful in considering shock and rarefaction effects across boundaries of different media... 

The gaseous products of deton move as a strong wind behind the shock front and are prevented by their own inertia from decreasing as rapidly as the pressure at the point of deton, As a result, there is produced a rarefaction effect and a point of reduced pressure, which condition trails the shock front. When the pressure becomes less than atmospheric, the wind rever-... 

Rarefaction Effect. See under Blast Effects in Air in Vol 2, B180-R... 

The Knudsen number (Kn) is used to represent the rarefaction effects. It is the ratio of the molecular mean free path to the characteristic dimension of the flow. For Knudsen numbers close to zero, flow is still assumed to be continuous. As the Knudsen number takes higher values, due to a higher molecular mean free path by reduced pressure or a smaller flow dimension, rarefaction effects become more significant and play an important role in determining the heat transfer coefficient. 

G. Croce, P. D Agaro, and A. Filippo, Compressibility and rarefaction effects on pressure drop in rough microchannels. Heat Transfer Engineering 28, 688-695 (2007). 

In general, the increased rarefaction effects in our flowrate model can be taken into account by introducing a correction expressed as rarefaction coefficient CfKn), which is a function of the Knudsen number. The flowrate is then obtained as... 

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