International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Liquid capillary bridges (CBs), created between two flat solid surfaces, parallel to each other, are of significant importance for number of scientific and industrial applications. In this paper, we present our experimental investigation of the liquid CBs at stretching, created by two immiscible liquids: cedar oil–water and paraffin-water with common interface. The behaviour of these binary structures was studied and compared with that of the single liquid CBs. It was found that the binary liquid CBs exist in the same definition domain as the single liquid CBs. Moreover, the current paper is focused not only on static, but also on non-equilibrium behaviour of CBs. We demonstrate that the binary liquid CBs can be engineered by the proper combination of polar (water) and non-polar (oil) fluids and these CBs exist within the theoretically predicted domain. The experimental results of water/cedar oil and water/paraffin binary CBs shows that the paraffin spreads in water surface and modifies the overall surface tension of the system, while the cedar oil and water retain their surface properties within the binary structure.

The problem of convective stability in a medium containing settling heavy solid particles are discussed. A study is made of the stability of steady convective flow of a medium containing an additive between vertical plates heated to different temperatures. It is shown that the presence of settling solid particles has a significant stabilizing effect on convective stability.

The results of a solution of the problem of the stability of steady convective flow in a vertical layer with thermally insulated boundaries and a comparison with the opposite limiting case of ideally thermally conducting boundaries are presented. Study is made of the effect of thermal properties of boundaries on the convective flow stability in a closed vertical layer. The numerical solution of a spectral amplitude problem for normal disturbance is presented for thermally insulated boundaries. The critical Grashof numbers are determined. A comparison with the case of ideal conducting walls shows that there is a slight effect of thermal properties on the instability criterion.