Rarefaction

About: Rarefaction is a research topic. Over the lifetime, 1852 publications have been published within this topic receiving 26943 citations.

Effects of Gas Rarefaction on Used Nuclear Fuel Cladding Temperatures During Vacuum Drying

Abstract: A two-dimensional computational model of a loaded used nuclear fuel canister filled with dry helium gas was constructed to predict the cladding temperature during vacuum-drying conditions. The mode...

Poiseuille flow in a capillary at all regimes of rarefied gas flows

Abstract: Functional structure of relations between the Poiseuille gas flow rate through the capillaries and rarefaction parameter (Knudsen number), the gas/surface interaction parameter (accommodation coefficient) and cross-sectional shape of the capillaries is established. For this purpose, the numerical solutions of the relaxation kinetic equation and the Boltzmann equation with specular-diffuse boundary condition for the interaction of gas molecules with the inner surface of the capillary are used. Asymptotic expansion of the gas flow rate depending on the Knudsen number at small value of it is used also.

Experimental and Numerical Investigation of Shock Wave Attenuation in Dust-Gas Suspensions

Abstract: The attenuation of planar shock waves while propagating through dust-gas suspensions was studied experimentally and numerically. The numerical solution was conducted twice, each time using a different correlation for the dust particle drag coefficient. It was shown that when the Reynolds number is relatively high (Re > 200) the solution based on the nonstationary drag coefficient provides better agreement with experimental findings. Also studied was the post shock pressure signature; good agreement was found between experimental and numerical results until the reflected rarefaction wave, from the driver’s end wall, caught up with the transmitted shock wave in the suspension.

Measurement of the slope of shock velocity-particle velocity Hugoniot curve for polymers

Abstract: In case of shock waves in polymers in the stress range of less than 1 GPa, a strategy to measure the slope of shock velocity-particle velocity Hugoniot curve is proposed. The method is based on the measurement of sound velocity at the shocked state as well as shock and particle velocity. The slope of Hugoniot can be evaluated by combining these values with the shock thermodynamic equation. Experiments were conducted for two kinds of polyethylene samples exhibiting peculiar shape of Hugoniot curve. An in-material PVDF gauge detects both a plane shock wave in polyethylene target induced by impact with a flyer plate and a rarefaction wave reflected from free surface of the flyer. Slope of the Hugoniot analyzed at several Hugoniot points for the polyethylene samples are consistent with their peculiar shape of the Hugoniot curves.

Convection in a porous medium with velocity slip and temperature jump boundary conditions

Abstract: The onset of convection in a rarefield gas saturating a horizontal layer of a porous medium has been investigated using both Darcy and Brinkman models. It is assumed that due to rarefaction both velocity slip and temperature jump exist at the boundaries. The results show that (i) when the degree of rarefaction increases the critical Rayleigh number as well as the critical wave number for the onset of convection increases, (ii) stabilizing effect of temperature jump is more than that of velocity slip, (iii) Darcy model is seen to be the most stable one when compared to Brinkman model or the pure gaseous layer (i.e. in the absence of porous medium).