METHOD OF DETERMINING DIFFUSION COEFFICIENT IN SHEET ORTHOTROPIC CAPILLARY-POROUS MATERIALS

摘要

FIELD: measuring equipment.;SUBSTANCE: invention relates to measurement equipment and can be used in investigation of mass transfer processes and determination of diffusion coefficients of solvents in orthotropic capillary-porous materials in paper, light, construction and other industries. Method for determining diffusion coefficient of solvents in sheet orthotropic capillary-porous materials consists in the fact that in the investigated sheet material there is created a uniform initial content of a solvent distributed in a solid phase, then analyzed material is placed on a flat substrate from solvent-impermeable material, waterproofing upper surface of material, at the initial instant of time, the analyzed material is pulsed wetted along a straight line by a moving solvent source of constant efficiency in a given direction of the orthotropic material, electrodes of a galvanic converter are made in the form of rectilinear sections and are arranged on both sides of the pulse humidification line on straight lines parallel to the pulse humidification line located at the same specified distance from it, wherein pulse exposure is carried out with a solvent dose calculated by formula G≈2.3hLρ₀U_px_c, and time moments τ₁ and τ₂ fixed when equal galvanic converter signal values are achieved in vicinity of 0.9 E_p value, where h is thickness of analyzed material; L is pulse action pulse length; ρ₀ is density of analyzed sample in dry state; U_p is the equilibrium concentration of the solvent in the analyzed sample upon contact with saturated solvent vapor at a given temperature; x_c – distance between electrodes of galvanic converter and line of exposure to solvent dose on surface of controlled article; E_p is galvanic converter signal value at concentration U_p.;EFFECT: technical result is higher accuracy of control and reduced time and costs for research.;1 cl, 1 dwg, 1 tbl