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The integrated effect on homogeneous and heterophase liquids that can be used for technological purposes has drawn the attention of researchers in various sciences. Cavitation impact on oil is among the efficient methods of intensifying chemical-technological, hydromechanical, and mass-exchange processes and the destruction of substances. This work reviews in detail and analyzes the mechanisms of impact and application of cavitation in various processes in the petroleum industry, including the refining processes, that are associated with crude oil and petroleum waste, such as reduction of viscosity, demulsification, desulfurization, and improvement of quality of heavy oil and petroleum refinery products, including oil sludge and waste oil-containing water.

Adaptation of a mathematical model of gas diffusion combustion for different flow rates of CO–H2 and a constant coal flow rate is carried out. It is shown that the results of calculating the main characteristics of the flame are in satisfactory agreement with experimental data and can be used to determine the structure of pulverized coal–gas flow, gas composition, particle and gas temperature, carbon combustion efficiency, etc. The proposed model is suitable for analyzing the stability of coal–gas flame and the transient processes accompanying changes in the mode of supply of the fuel-oxidizer medium.

It is common to use coal as raw material in heat power engineering. A number of shortcomings of coal such as ignitability cannot be easily eliminated. The use of water-slurry-based coal-water fuel instead of coal eliminates this problem. The coal-water fuel (CWF) is liquid fuel, which means that the main line of investigation is to study its sedimentation and rheological properties responsible for the transport and atomization in the boiler and thermal-physical properties which determine the expedience and efficiency of its application. The paper shows that the final performance properties of suspended coal fuel can be determined at the stage of CWF preparation by hydrodynamic treatment of aqueous coal slurry. The rheological and sedimentation properties and combustion parameters of water-coal fuel, ignition time of the drop, its completeness of combustion, and amount of man-made emissions, have been studied. Studies have been carried out on coals from the Kansk-Achinsk coal basin (Russia). The studies were performed under laboratory conditions with a hydrodynamic rotary mixer, making it possible to attain cavitation effects in the processed medium. Two CWF types have been considered: the first was produced by cavitation dispersion of the solid coal fraction in distilled water, and the second was produced in analogy, but the dispersion medium was water pretreated by cavitation. The paper shows that the cavitation method of producing CWF improves the rheological and sedimentation properties of the end-use fuel, reduces hazardous emissions in combustion, and affects the combustion parameters.

The results of a numerical study of the effect of nanoparticle additives in the drilling fluid on the efficiency of cuttings removal from a horizontal well are presented. The rheological parameters of drilling fluids with nanoparticles (NPs) were set from the experiment. The SiO2 and Al2O3 NPs were used. The concentration of NPs in the drilling fluids varied from 0.25 to 2 wt%, while their average diameter ranged from 5 to 50 nm. The Eulerian granular media approach was used to simulate the cutting transport from the borehole. The numerical model was tested in detail on well-known experimental data on sand suspension flow in a round pipe. A good agreement with the experiment was obtained. A systematic computational study of the influence of several parameters on the efficiency of removing cuttings from the well was carried out. These parameters included the well's inclination angle from the vertical direction, the speed of rotation of the drill pipe, the flow rate of the drilling fluid, and the concentration, size, and composition of nanoparticles. It is shown that the 2 wt% concentration of nanoparticles in the drilling fluid results in a 2.7-fold increase in the cutting transport performance for horizontal boreholes. The positive effect of adding nanoparticles to the drilling fluid is enhanced with decreasing nanoparticle size.

This article presents experimental data on the coefficients of viscosity and thermal and electrical conductivities, as well as the absorption spectra, of suspensions of ultradispersed diamonds. Suspensions of UDA-S and UDP-A detonation nanodiamond particles, as well as UDP-AG diamond–graphite powder, are used in the experiments. The concentration of nanodiamonds in distilled water is varied within a range of 0.5–5 wt %. It is shown that the technology of purification diamond powders from side products of their synthesis substantially affects the physicochemical properties of aqueous suspensions of these powders.

The mathematical model of heat and mass transfer processes in the combustion chamber of diesel generator units with valve inductor generators has been developed. The mathematical model takes into account the actual geometry of the combustion chamber and the operating conditions of the diesel engine. A study of the main characteristics of a diesel generator in a wide range of modes of operation has been carried out. In addition to energy characteristics, environmental parameters have been considered

The systematic experimental investigation of the viscosity of more than 30 different nanofluids was carried out. The investigated nanofluids were prepared based on distilled water, ethylene glycol ...

The viscosity coefficient and thermal conductivity of suspensions with single-wall carbon nanotubes have been experimentally studied. The nanotube mass concentrations are varied from 0.05 to 0.25 wt %. The suspensions exhibit non-Newtonian behavior. The dependences of the rheological suspension parameters on the nanotube concentration are obtained. It is established that the properties of the carrier liquid affect the viscosity coefficient and thermal conductivity of the suspensions.

The unique properties of supercritical fluid technology have found wide application in various industry sectors. Supercritical fluids allow for the obtainment of new types of products with special characteristics, or development and design of technological processes that are cost-effective and friendly to the environment. One of the promising areas where supercritical fluids, especially carbon dioxide, can be used is the oil industry. In this regard, the present review article summarizes the results of theoretical and experimental studies of the use of supercritical fluids in the oil and gas industry for supercritical extraction in the course of oil refining, increasing oil recovery in the production of heavy oil, hydraulic fracturing, as well as processing and disposal of oil sludge and asphaltenes. At the end of the present review, the issue of the impact of supercritical fluid on the corrosion of oil and gas equipment is considered. It is found that supercritical fluid technologies are very promising for the oil industry, but supercritical fluids also have disadvantages, such as expansion or incompatibility with materials (for example, rubber).

The results of an experimental study of the interfacial tension and surface wettability in the nanosuspension/oil/rock system are given. The effect of the concentration and size of silicon oxide nanoparticles on the coefficient of interfacial tension and the contact angle of wetting has been systematically studied for the first time. A wide range of weight concentrations of nanoparticles (from 0 to 1 wt %) and their average sizes (from 5 to 50 nm) are considered. It is established that the use of nanosuspensions makes it possible to radically change the wettability of rocks with respect to oil. In this case, this effect depends substantially on the concentration and size of nanoparticles.

Evaporation of nanofluids based on distilled water and silicon-dioxide, zirconium-dioxide, aluminum oxide, and diamond nanoparticles has been experimentally studied. The mean nanoparticle sizes are 25 nm for SiO2, 105 nm for ZrO2, 43 nm for Al2O3, and 5 nm for diamond. Evaporation processes have been investigated using an STA 449 C Jupiter (NETZSCH) simultaneous thermal analyzer. The dependence of the evaporation rate on the nanoparticle volume concentration has been studied. It is shown that the fluid evaporation rate monotonically increases with an increase in the nanoparticle concentration.

The authors have performed numerical simulation of pressure pulsations in the draft tube of a hydraulic turbine that are excited by large-scale vortex structures. Numerical simulation of unsteady transfer in the draft tube in different operating regimes of the turbine has been carried out. It has been shown that the structure of flow in the outlet diffuser corresponds to vortex-core flow. Calculated data have been compared with experimental results and their agreement has been shown. To suppress pressure pulsations, a study has been made of the influence of various structural inserts into the draft tube, such as fins, a cross piece, and a hollow cylinder in the draft-tube cone. Consideration has been given to the influence of various constructions on the structure of flow behind the wheel and on pressure pulsations on the draft-tube wall. A comparison has been made of the constructions and optimum parameters have been selected to stabilize the flow in the diffuser of the hydraulic-turbine draft tube.

An experimental study was carried out to investigate the effect of adding nanoparticles of different size and materials on the friction coefficient of water-based drilling muds. Silicon oxides and ultradisperse diamond particles were considered as the nanoparticles. An aqueous bentonite solution with a mass fraction of 5% was used as the basic drilling mud model. The nanoparticle concentration in solutions ranged from 0.06 to 2.00 wt %. The size of nanoparticles ranged from 5 to 100 nm. It was shown the adding nanoparticles to drilling muds significantly decreases the friction coefficient, the value of which depends on the size of nanoparticles and changes appreciably at low concentrations.

Experimental investigation of the deposition of nanoparticles in a circular channel in a constant magnetic field has been carried out. The dynamics of growth of nanoparticles deposits on the channel walls depending on the Reynolds number and magnetic field strength has been studied in the experiments. The influence of magnetic field on pressure drop at different Reynolds numbers has been investigated. Characteristic profiles of the zones of nanoparticles depositions have been obtained for the first time; the sizes of the deposition areas and the rates of their formation depending on the Reynolds numbers, magnetic field strength and time have been determined.

The experiment investigation of laminar forced convection of nanofluids with Al2O3, TiO2, ZrO2 and diamond nanoparticles was carried out. Nanoparticle concentration varied in the range from 0.25 to 6 vol% in the experiments. The nanoparticle size ranged from 5 to 150 nm. The dependence of heat transfer coefficient and pressure drop from the concentration, size, material of the nanoparticles was studied. It was shown that adding nanoparticles to the coolant significantly influences the heat transfer coefficient in the laminar flow regime. It is shown that with increasing nanoparticles concentration, the local and average heat transfer coefficients at a fixed Reynolds number increase. The effect of nanoparticles material on the heat transfer coefficient has been also demonstrated. It was shown the effect of properties of the base fluid on the heat transfer coefficient nanofluids was considered. The effect of rheology nanofluids on the heat transfer coefficient was analyzed.

The interdisciplinary problem on the influence of power loss of microwave signals transmitted by waveguides on their thermoelastic condition is considered. The estimation of the temperature field is carried out based on the developed mathematical model with the differential equation of the thermal balance of the waveguide, which takes into account the different conditions of its operation and which is solved using the finite difference method using the program developed.

A mathematical model of the conjugate heat transfer of the well was developed subject to phase transitions and drilling fluid circulation during the drilling. Calculations were carried out for the permafrost thaw process around a well while drilling using by solutions with different ethylene glycol contents. It was established the main regularities of conjugate thermohydraulic processes during the drilling of permafrost subject to thawing and solution circulation. It was shown the addition of ethylene glycol leads to a decrease of the heat transfer coefficient and the quantity of heat entering the well, which in turn leads to a significant slowdown in the thawing permafrost process

Paper reports on optical diagnostics and numerical simulation of the flow structure and transport of a passive scalar in a turbulent swirling jet with vortex core breakdown. Based on the measurements of the instantaneous velocity and concentration fields by PIV and PLIF techniques, the Reynolds stresses and Reynolds fluxes are evaluated and compared to those obtained from URANS and LES simulations. Based on the experimental data and LES-simulation results, the local convective and turbulent transport of the passive scalar are analyzed.

The electric conductivity is experimentally studied in nanofluids based on water and ethylene glycol containing copper and aluminum particles. Other properties, such as heat conductivity and rheological characteristics, were evaluated as well. The electric conductivity of nanofluids is shown to increase almost linearly with a nanoparticle concentration, but, unlike the heat conductivity, a gain in electric conductivity is due to a decrease in particle size. In this respect, the mechanisms of electric conductivity and heat conductivity are assumed to have the fundamentally different nature.

The results of the numerical study of oil recovery enhancement using nanosuspension are presented. The research was carried out using the volume of fluid method (VOF) for a 2D microporous core model. Experimentally measured values of interfacial tension (IFT) and the contact angle (CA) were used for numerical modeling. An aqueous suspension with silicon oxide nanoparticles (5 nm) is used. It was shown that when 1 wt% of nanoparticles are added to the displacing liquid, its density increases by about 1%, the viscosity increases by 10%, the IFT decreases by 10%, and the contact angle increases from 70 to 145 $$^\circ $$ . The results of numerical study showed that the injection of nanoparticles has a significant effect on the displacement front movement in the microporous model. It has been shown that the nanosuspension can increase the oil recovery factor (ORF) almost twice as compared to water. To clarify the mechanisms of increasing the oil recovery during the reservoir flooding with nanofluid, a systematic study of factors affecting the displacement process efficiency was carried out. Viscosity, interfacial tension and the wetting angle of the displacing fluid were considered as such factors. As a result of systematic research, it has been shown that the main factor affecting the increase in the oil recovery flooding of nanosuspensions is a variation of wettability.

In this paper, we present the results of a systematic numerical study of the flow and mixing modes of fluids in micromixers of various configurations, in particular, an analysis of passive micromixers, the most widely used in practice, as well as the main methods to intensify mixing. The advantages of microstructure reactors can significantly reduce reaction times and increase productivity compared to traditional bulk reactors. Four different geometries of micromixers, including the straight T-shaped microchannel, were considered. The effect of the geometrical patterns of micromixers, as well as of the Reynolds number on flow regimes and mixing efficiency were analyzed. The Reynolds number varied from 1 to 300. Unlike other studies, the efficiency of the considered mixers was for the first time compared with the cost of pressure loss during pumping. As a result, the efficiency of the most optimal micromixer in terms of hydraulic mixing and the optimal operation ranges were determined. It was shown that the maximum normalized mixing efficiency in the entire range of Re numbers was noted for mixer, in which a vortex-based intensification of mixing occurs due to the flow swirling in cylindrical chambers. This mixer allows mixing the fluids 600 times more efficiently than a straight T-mixer, while all other conditions being equal.

A brief analysis is provided for the energy consumption to overcome the resistance of a gas layer generated during electrolysis beneath the aluminum electrolytic cell anode, and basic concepts are provided for reducing the volume of a gas layer beneath the anode. A technical solution is proposed providing separation of the self-baking anode into individual units in a common anode housing that improves significantly not only energy, but also ecological parameters of the aluminum electrolyzer. Mathematical modeling is provided for anode gas behavior under a monoblock and a self-baking anode block. On the basis of analyzing the data obtained it is revealed that the use of a block anode reduces the electrolyzer energy required in a cell by 3–5%, improves cell productivity by 10–12%, and reduces by half the number of burners in used in the electrolysis vessel.

This study presents a systematic investigation of viscosity and rheological properties of several dozen emulsions and nanoemulsions. The concentration by volume of the oil in emulsions varied from 20% to 80%. Low-viscosity mineral oils were used for emulsion formation and an aqueous solution of calcium chloride was used as the second medium. The volumetric concentration of emulsifiers varied from 1.5% to 4.5%. Three types of mineral oil, as well as various emulsifiers, are considered. The effect of the volumetric content and base oil type, the emulsifier type and concentration and the ultrasonic treatment duration on colloidal stability, rheological properties and droplet size of the resulting emulsion has been studied. It is shown that emulsions are considered to be non-Newtonian fluids with apparent elastic properties at oil concentration less than 35 vol.%. All other things being equal, the average droplet size in the emulsion increases with an increase in the base oil viscosity. The use of ultrasonic treatment makes it possible to reduce the average droplet size in the emulsion by 4.5 times and to reduce its viscosity by 1.5 times.

Combustion of n-heptane in a laboratory pattern of an original evaporative-type burner with the supply of air or superheated steam to the reaction zone was studied experimentally and numerically. Turbulence was simulated on the basis of the k-ω SST RANS model. Combustion was simulated using the Eddy Dissipation Concept (EDC) model with a detailed kinetic mechanism. The developed mathematical model was verified; a good agreement between calculation results and obtained experimental data is shown. For the first time, a comparative analysis of the effect of forced supply of steam and air on the local and integral characteristics of combustion is carried out. Radical difference in the effect of steam supply in comparison with air supply on reducing emissions of nitrogen oxides and soot from the burner is shown. The burner operating regimes have been studied in detail in a wide range of flow rates of supplied steam and fuel. It has been found that with an increase in steam flow rate, underburning, soot formation and production of nitrogen oxides are significantly reduced.

The effect of nanoparticles of various chemical components and sizes on the rheological behaviour of drilling fluids, pressure loss and cuttings transport in the vertical borehole for a laminar flow regime is considered in the paper. The results of numerical and experimental studies are presented. Silicon, aluminium and titanium oxides nanoparticles are considered. A drilling fluid is Bentonite-water solution with a mass fraction of 5%. The particles concentration in the solution was varied from 0.25 to 2 wt percentages and the particles sizes ranged from 5 to 50 nm. The dependences of the effective viscosity and rheological parameters of the solutions on the nanoparticles concentrations, sizes and materials were obtained. It was shown that nanoparticles in drilling fluid increase cuttings transport by 17% and decrease the average slip velocity of the sludge particles in 1.7–2.0 times, but the pressure losses when pumping the drilling fluid increase in 2.5 times.