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Data of experimental studies on hydrodynamics of countercurrent flows of liquid and vapor in distillation columns with structured packings are necessary for verification of computational models that describe hydrodynamics and processes of heat and mass transfer in industrial distillation columns. The paper presents a description of the design of a multipoint hot-wire anemometer with a coordinate device, developed to measure the steam flow rate under conditions of jet irrigation of the packing with a countercurrent flow of freon mixture phases. The measurement system was tested with air flowing through a 210-mm layer of Sulzer 500X structured packing. The measurements were carried out using a large-scale research model of a distillation column with a diameter of 900 mm. Experimental data were obtained on the distribution of the local air flow velocity at the outlet of a single-layer Sulzer 500X packing. Scanning the packing plug with a step of 1 and 5 mm showed the presence of a periodic cellular pattern of the gas flow velocity distribution, which correlates with the structure of the studied packing.

The Direct Simulation Monte Carlo (DSMC) method is used to study rarefaction effects on the structure of an axisymmetric underexpanded jet. A comparison with the data of other researchers shows that DSMC simulations accurately reproduce the features of the steady shock-wave structure of the jet. Rarefaction produces a noticeable effect on the jet flow. In particular, it makes the barrel shock in the first shock cell change the type of its reflection from the axis, which leads to vanishing of the developed Mach disk and to changes in the structure of other shock cells. For the first time, the formation of a closed reverse flow region behind the Mach disk is observed in a molecular-kinetic simulation. This phenomenon has been earlier observed only in continuum simulations.

The influence of asymmetric boundary conditions on flow regimes in a model hydraulic turbine has been investigated. The curved draft tube is shown to have almost no effect on the vortex structure, preserving such a phenomenon as the re-connection of the vortex core. The axial and tangential velocity profiles also remain unchanged. There is a change in pressure pulsations, despite the similarity of the average values and the unsteady vortex flow pattern. In the case of an asymmetric model, the pressure pulsation is higher than for a symmetric model. This may indicate a superposition of pulsations, caused by the rotation of a precessing vortex core, with generated longitudinal (synchronous) pressure fluctuations.

The paper presents the research into small multirotor vehicles that fly in the surface layer of the atmosphere, where the level of flow disturbances impinging on the blade can change significantly, altering the characteristics of the propeller. Axial streamlining of a constant-pitch two-blade rotor with a diameter of 380 mm was experimentally studied in a low-noise wind tunnel T-324 of ITAM SB RAS. The experiment was carried out in the range of Reynolds numbers up to 1.5∙10⁵, calculated from the flow parameters in the cross section of 75% of the rotor radius. The thermoanemometric method was used as the main measurement method. The influence of pulsations of the incoming flow on the flow characteristics in the propeller wake was established.

In this paper, the characteristics of the electric field, flow field and temperature field of ionic wind heat sink are studied, respectively. The results show that the heat sink achieves the best performance when the ratio of fin spacing to thickness is 5, the electrode spacing is 5mm, the needle position is 0. Furthermore, a two-stage structure ionic wind heat sink is proposed and optimized. The optimized average wind velocity increased by 30.8% to 3.57m/s compared to the single-stage structure. This work enriches the knowledge of electrode configuration and promote the application of ionic wind heat sinks.

The operation of the centrifugal disk pump is experimentally studied. To summarize experimental data, dimensionless parameters are introduced. A method for calculating the flow rate, pressure, and throttle characteristics is proposed. The method ensures accuracy sufficient fort engineering calculations.

The RANS approach was used for revealing the phenomenon of interference of a jet flow while deceleration due to interaction with the windward edge of the inclined groove on a streamlined plate and the narrow trench wall; the interaction generates a tornado-like vortex at the groove inlet. Experiments confirmed emerging of extra-ordinary drops in static pressure between the stagnation and rarefaction zones. The return flow velocity increases twice and this velocity magnitude exceeds the superficial velocity. The study justified the separation flow increase and heat transfer enhancement for the cases of inclined grooves on a structured surface. This effect is related with a multiple (up to 6-9 times) growth of relative friction and heat fluxes inside the grooves (compared to the case of a flat wall). We observe also acceleration in the near-wall stream caused by a set of single-row inclined groves in a narrow channel. Here the maximum velocity in the stream core in a structured channel increases by more than 1.5 times as compared the maximal velocity for a flow in a planar-parallel channel. The study performs aerodynamic disigning of new energy-efficient grooves-structures surfaces.

Four options for the power cycle using carbon dioxide as a working fluid during oxygen combustion of gaseous fuel are considered. In all the cases, heat is supplied in the zone of supercritical parameters of CO₂. The fundamental difference in options lies in the method of increasing the working fluid pressure. The heat is supplied to the cycle in the combustion chamber, and the cycle operation is accompanied by continuous updating of the working fluid, since part of CO₂ and all steam obtained during fuel combustion are removed from the cycle. It is shown that cycles with a single-stage pump pressure increase have the highest thermal efficiency, reaching 64.5%. The effect of thermodynamic parameters on the energy characteristics of cycles has been estimated quantitatively.

Results of numerical simulation of the combustion of a gas-droplet fuel mixture in an oxidizer flow under conditions typical of hybrid rocket engines are reported. The effect of the size and rate of supply of fuel droplets on the combustion completeness, temperature and position of the diffusion flame in the boundary layer of the oxidizer flow has been studied. It is shown that the influence due to the liquid fuel droplets manifests itself as a local decrease of gas temperature and an increase of the concentration of the gaseous fuel in the immediate vicinity of droplets. The addition of droplets to the gaseous fuel flow results in a slight decrease of the flame thickness and flame temperature, which, however, experience no large-scale perturbations as a result of droplet movement and remain almost stationary.

Combustion of liquid hydrocarbons by spraying them with a jet of superheated steam, carbon dioxide and air has been experimentally studied. Results aimed at identifying the advantages of using superheated steam as a diluent sprayer over other diluent gases were obtained at the example of diesel fuel. For this, thermocouple measurement data were studied and compared, gas analysis of intermediate flame components was performed when fuel was sprayed with various diluent atomizers, and both combustion efficiency and harmful emissions in the final combustion products were compared. It was found that the air spray regime has a higher flame temperature (~ 150°С) in the entire measured range as compared to steam and carbon dioxide spray. At the same time, the regimes with steam and carbon dioxide have similar temperature profiles. Exhaust gas analysis showed that when sprayed with steam, the reduction in NO_x reaches 25 and 70% relative to carbon dioxide and air, respectively, which makes its use as a diluent atomizer more preferable when burning liquid fuels as compared to other studied gases.