2014, №2

сс. 27-39

Relaxation of fibrillar porous media saturated with carbon dioxide in the vicinity of its critical point

2014, №2

сс. 27-39

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D.A. Zimnyakov, S.P. Chekmasov, O.V. Ushakova, V.N. Bagratashvili

Key words: fibrillar porous media, subcritical liquid, supercritical fluid, bulk modulus, relaxation of deformations, speckle correlometry

Isothermal relaxation of deformations in the fibrillar porous layers saturated by
subcritical or supercritical carbon dioxide is studied using full-field speckle correlometry
at various temperatures. The relaxation of deformations is caused by the transition of
the «porous layer — fluid» system from one equilibrium state to another as a result of
partial drop of pressure. It is found that the relaxation time reaches its maximal value
in the vicinity of the critical point and rapidly falls down with the increasing deviation
of the system temperature from the critical temperature of carbon dioxide. Possible
mechanisms of hydrodynamic relaxation of the fluid density inside the layer and
viscoelastic relaxation of the porous matrix are discussed. It is shown that the
experimentally observed slow relaxation of the system is governed by the viscoelastic
relaxation of the porous matrix in the condition of equal values of the fluid density
inside the layer and outside it.

doi:10.1134/S1990793115070167