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The research presents the numerical modeling findings of the secondary breakup of droplets of coal water slurries containing petrochemicals (CWSP) droplet with the filter cake content of 50 % for different Weber number values. The modeling method of the secondary droplet breakup is based on the VOF method for interface resolution, LES model for describing turbulence, and the technology of adapted dynamic grids. This technology enables the grid to be automatically concentrated in the region of large solution gradients during the calculation. The implementation of such a highly detailed grid allowed resolving secondary droplets with the dimensions down to 15 μm. We established the droplet breakup modes depending on the Weber number ranging from 36 to 342. The structure of the stream behind droplets was studied in detail and the numerical method was tested. The results are in good agreement with the results of known experiments.

The article presents the initial stage of developing a hybrid mathematical model for describing the recovery of oil from a natural sand reservoir. The hybrid model means that part of the computational domain (microchannel structure in the space between particles) is calculated by one- dimensional models is based on the hydraulic circuit theory, and another part (large cracks and caverns) is calculated by computational fluid dynamics methods (CFD). The article also describes a unique algorithm for building a network model based on preliminary CFD calculation. The last section of the article presentation compares of results of calculation CFD and network models.

The paper presents an experimental study of oscillatory response in the Francis turbine of hydraulic unit. The experiment was performed on large-scale hydrodynamic test-bench with impeller diameter of 0.3 m. The effect of air injection on the intensity of pressure pulsations was studied at the maximum pressure pulsations in the hydraulic unit. It was revealed that air delivery into the water-conveyance system of the turbine results in almost two-fold reduction of pressure pulsations.

The paper presents testing results of the numerical technique to simulate the agitation process of concentrated suspensions. The simulating technique is based on Eulerian two-fluid model of granular media, k-w SST URANS turbulence model, and sliding mesh approach. The results obtained show a good qualitative and quantitative agreement between calculation and experiment in terms of the shape and location of the phase interface and the distribution of the solid phase along the height.

The paper presents an experimental study of the relationship between the vibration of the water turbine unit and the pressure pulsations in the flow path. It is shown that the air injection into the flow path leads to a decrease in the hydraulic turbine vibration associated with the formation of the precessing vortex core.

The paper presents an experimental study of oscillatory response in the Francis turbine of hydraulic unit. The experiment was performed on large-scale hydrodynamic test-bench with impeller diameter of 0.3 m. The effect of air injection on the intensity of pressure pulsations was studied at the different regimes in the hydraulic unit. It was revealed that air delivery into the flow path system of the turbine results in almost two-fold reduction of pressure pulsations, but for optimal regimes, there is an increase in pressure pulsations.

Experimental study of the magnetic nanofluids forced convection in a constant magnetic field was carried out. Dependence study of the magnetic nanofluid heat transfer coefficient on the effect of a constant magnetic field was made. The effect of a constant magnetic field on the pressure drop during the magnetic nanofluid flow was shown.

During the research we conducted an experimental study and numerical simulation of ferromagnetic nanoparticles transport behavior in a constant magnetic field. The growth dynamics of nanoparticle deposits on channel walls was studied depending on the Reynolds number and the intensity of the magnetic field. We obtained flow pattern, the concentration field and the trajectory of nanoparticles depending on the Reynolds number. The simulation results were compared with data from experiments. There was good qualitative and quantitative agreement between calculation and experiment.

In this paper, the study of ferromagnetic nanoparticles behaviour in the constant magnetic field is carried out. For numerical simulation we have used Euler-Lagrange two-component approach. Using numerical simulation we have studied the growth of deposition of nanoparticles on the channel walls depending on the Reynolds number and the position of the magnet. The flow pattern, the concentration field and the trajectory of nanoparticles as a function of the Reynolds number were obtained. The good qualitative and quantitative agreement between numerical simulation and experiments was shown.

The free discharge through the turbine is applied in the course of construction of hydro power plant or in case of excessive water inflow during floods or emergency situations. The experimental and numerical investigation of flow-induced pressure pulsations in hydraulic turbine draft tube at free discharge was performed using a special setup for suppression of draft tube surge. Such special equipment in draft tube cone as fins and “spider”-like units was considered for reducing these pressure pulsations. The paper considers influence of these units on vortex structures and pressure pulsations in the draft tube in several regimes.

The thermal conductivity of magnetic nanofluids in a constant magnetic field is investigated. The concentration dependence of the thermal conductivity coefficient of magnetic fluids based on water and iron oxide nanoparticles Fe3O4 in a constant magnetic field is obtained. The dependence of the thermal conductivity coefficient of nanofluid on the nanoparticles size in a magnetic field is obtained. The temperature effect on the thermal conductivity of magnetic nanofluid in a constant magnetic field is studied.

Flow patterns and mixing of liquids with different densities in T-shaped micromixers are numerically investigated at Reynolds number range from 1 to 250. The density ratio of the mixing media varies from 1 to 2; its effect on the flow structure and the mixing is studied. The dependences of the mixing efficiency and the pressure difference in this mixer on the density ratio and the Reynolds number are obtained. It is shown that the density ratio has a considerable effect on the flow structure, especially before the transition from the symmetric to the asymmetric flow pattern.

Saturated boiling of nanofluid on a copper cylinder is experimentally studied. The studied nanofluid were prepared using distilled water and Al 2 O 3 nanoparticles. The volume concentration of the nanoparticles was equal 3 %. Cylinder diameter was equal 25 mm. The time dependence on the excess temperature at different boiling regimes were obtained. It shown increase of heat transfer coefficient under boiling of nanofluid.

The experimental study of influence of adding high-molecular weight polymers on heat transfer characteristics of water-based nanofluids with Al 2 O 3 nanoparticles. Volumetric concentration of particles was very low, 10-3 %. The volumetric particle concentration was equal to 2%. We investigated the dependence of heat transfer coefficient and pressure drop on the concentration of additives high polymers.

Saturated boiling of nanofluids on a cylindrical heater with different diameters is experimentally studied. Studied nanofluids were prepared using distilled water and different metal oxides nanoparticles. The volume concentration of the nanoparticles was changed from 0.05 to 1%. It has been measured that the critical heat flux for nanofluids was much higher than for water. A strong dependence of CHF on the material and size of the nanoparticles and duration of boiling and size of heater was shown.

This article investigates electrolyte filtration in the bottom of the aluminum electrolyzer cathode device using the mathematical modeling. Penetration of molten electrolyte in the heat insulation part of the lining is one of the main reasons of electrolyzer premature shutdown, because it leads to bottom destruction and excessive heat loss. This problem is considered a two-phase filtration of incompressible immiscible liquids in an inhomogeneous non-deformable porous body. The verification of the model on the problem of water filtration pin a porous medium has confirmed its adequacy. With the help of the developed mathematical model the dynamics of the impregnation of the lining of the cathode and electrolyte device defined thermal balance baths. Research has identified the speed of penetration of the melt in the bottom of the bath during service of the electrolyzer.

Results of testing methodology for calculating two-phase flows based on the method of fluid in the cells (VOF method), and the procedure for CSF accounting of surface tension forces in the microchannel are considered in the work. Mathematical modeling of two-component flow fluid -fluid in the T- microchannel conducted using this methodology. The following flow regimes studied slug flow, rivulet flow, parallel flow, dispersed (droplet) flow, plug flow. Comparison of numerical results with experimental data done. Satisfactory agreement between the calculated values with the experimental data obtained.