EVALUATION OF THE FEATURES OF THE STRUCTURE OF WATER AND AQUEOUS SOLUTIONS NEAR A SOLID SURFACE

The paper evaluates changes in the structure of water and aqueous solutions of sodium chloride in the wall layer on the basis of dielectrometry and correlation analysis. It is shown that when the distance to the solid surface decreases, there is a multi-fold nonlinear decrease in the electrical capacitance and a nonlinear change in the Sr parameter, which characterizes the magnitude of the change in the electrical capacitance of the conduction fluid when the distance to the solid surface changes. The parameters used in the work (electric capacity of liquids and Sr ) can be used to evaluate the changes in the structural organization of aqueous solutions in the wall (boundary) layer and to interpret the processes occurring in the liquid layer at the interface of the solid – aqueous solution phases.

A Finite Volume Method using a Quadtree Non-Uniform Structured Mesh for Modeling in Electrical Capacitance Tomography

An electric field solver based on a finite volume method using refined structural mesh is proposed to implement a quadtree structure and estimate the electric flux in the mesh cell. Numerical experiments were carried out using uniform and non-uniform meshes to assess quality of numerical modeling. The proposed method of verification of the quality of numerical calculations based on circular symmetry of the electrical capacitance tomography (ECT) probe allows to assess the effectiveness of mesh refinement and to reduce the number of mesh elements. Experiments showed that even a moderate level of mesh refinement is sufficient to significantly reduce the simulation error that occurs in modeling of cylindrical probes. The reduced number of mesh elements and applied implementation of the quadtree ensures high speed of forward problem calculations.