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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.

The research was devoted to the problem of measuring geometric parameters of ice by the method of phase triangulation in a limited volume with refraction of optical signals. This method served to develop an algorithm of measurement and calibration. It was also expedient to take into account the reflective properties of ice and the conditions of external lighting, as well as to ensure a minimum error in measuring the geometric parameters of ice. For this purpose, software complexes to control the quality of the measuring system with current parameters and to calculate the geometric parameters of ice, as well as a software and hardware complex for measuring the geometric parameters of ice by the phase triangulation method in a limited volume with refraction of optical signals have been developed. The measuring system was configured for a measuring volume with characteristic dimensions (100×100×60) mm. A measurement error of 12 microns has been achieved. Experiments were carried out to measure the geometric parameters of ice formed on a cylindrical surface. The values of the local thickness of the ice and the statistical value of the thickness of 1.6 mm have been restored. The developed technologies may be used in experiments on an aerodynamic stand for the study of icing processes aimed at creating anti-icing methods in various fields of industry.

The article presents the results of measurements of thermal conductivity coefficients of Pb-Na with the content of the latter of 20 at. % and eutectic (Pb-Bi)-Na 20 at % alloys at temperatures of 350 - 800 °С. The experimental methodology is described and the temperature differences in the heat-conducting sublayer of fuel cells of the studied alloys are estimated.

The density of liquid lithium fluoride and an eutectic mixture of lithium fluoride and sodium fluoride (with a content of 39 mol. % NaF) was measured by the gamma ray method in the temperature range from liquidus to ~1280 K. The obtained results were compared with the available literature data. The study of liquid eutectic LiF - NaF was carried out in a significantly wider temperature range compared to other authors, and the obtained values of the volumetric coefficient of thermal expansion turned out to be the most reliable.

A new thermal equation of state for methane is proposed in explicit form, including a crossover function. This function comprises new regular and scaling parts with 22 adjustable coefficients written in real temperature-density variables. The coefficients are determined from the ρ, ρ, T-data for CH4. Data on the heat capacities C_v, C_p and the speed of sound W were not involved in calculations, except for the data on the isochoric heat capacity C_v in the ideal gas state and the C_v value at 100 K on the liquid branch of the liquid-gas equilibrium curve. In the regular region, the calculated values of C_v, C_p, and W are close to the experimental and tabulated values. In the critical region, the discrepancies with the tabulated values are no more than 5%, which is associated with the use of the scaling equation of state. The average absolute deviation is 0.3% in the pressure description, the r.m.s. error σ_p = 0,5 %, and the error in C_v is less than 5%. The calculation results are compared with the known crossover equations of state for CH4. It is concluded that the proposed model of the equation of state is preferable for calculating the thermophysical properties of methane.

Dynamics of gas bubble growth in a highly viscous gas-saturated liquid (magmatic melt) subjected to decompression is investigated. A mathematical model of the process, which is a joint dynamic and diffusion problem, is proposed. An approximate semi-analytical solution is found based on the existence of a quasi-stationary state for the bubble growth process. The influence of certain factors on the process under consideration at all its stages is shown. In particular, a significant dependence of the bubble growth rate on the decompression rate is illustrated. It is shown that, at long times, bubble growth has a self-similar character and occurs only as a result of gas desorption from the surrounding liquid.

The paper considers a model of nucleation of crystal phase during cooling of a modified melt below the liquidus point. We demonstrated a connection between the overcooling factor, nucleus size forming at the particle surface, and the amount of consumed energy. Numerical simulation was performed for solidification of a modified bicomponent aluminum melt in a cylindrical crucible with account for thermodynamics, heterogeneous nucleation and crystallization. We found the conditions of crystal nuclei formations: both for the cases with the size higher or smaller that the size of seeds. It was shown that efficient modification of the metal needs the use of powders with maximally homogeneous size. The reliability of this model is confirmed by reasonable compliance between the simulation and physical experimental data.