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Development of concepts for multi-entry space vehicles put strict requirements to reliability of operating power plants and the flight vehicle as whole. An important problem is achieving trouble-free performance of vehicle power plant operating under high thermal loads. This type of power plants consumes the hydrocarbon fuel with a high resistance to surface deposition of incomplete oxidation products. The progress in production technologies for synthetic fuel from bio resource enables accessibility with reduced or zero carbon footprint. Synthetic fuel or its components are different from a hydrocarbon fuel by their composition, as well as by the fuel properties. The use of fuels with synthetic components requires a study on physical and chemical properties and thermophysical characteristics. This paper presents experimental study on thermal stability, limiting cooling capacity and ignition parameters for a high-density hydrocarbon fuel (HDHF) from new-generation products. It was shown that the HDHF can be used at temperatures up to 300 °С without any deposits of with admissible low levels. Experiments were conducted on the fuel ignition delay time for the operating range of pressure 14 - 16 bar, temperature 1000 - 1500 K and the access oxidant ratio 0.5 - 3 using the facilities of a shock tube.

The thermal diffusivity (α) of solid magnesium-lithium alloys with lithium contents X_Li = 5, 10, 17, 21, and 25 at. % was measured using a laser flash method in the temperature range of 300 - 680 K. Based on the experimental results, the thermal conductivity (λ) of alloys was calculated and compared with the literature values for λ of other compositions. The estimated uncertainties of the obtained data were 3.0 - 3.4 % for λ and 2.0 - 2.4 % for α. It is shown that the addition of lithium to magnesium reduces significantly its thermal conductivity, with a more pronounced decrease in λ observed as the Li concentration approaches X_Li = 32 at. %. Anomalous features in the form of bends in the temperature dependences λ(T) and α(T) were identified for the Mg₉₅Li₅ and Mg₇₅Li₂₅ alloys within the temperature range of 310 - 330 K, similar to the behavior reported for the Mg₇₀Li₃₀ alloy. Using the calculated data and literature sources, the concentration dependences of thermal conductivity for the Mg-Li system were plotted over the composition range X_Li = 0 - 32 at. %.

We propose to improve a new experimental methodology of determining the amplitude-frequency characteristics of a system of hot-wire anemometry with the use of a short-pulse laser action on the hot-wire sensor. Mistakes of the previous study are taken into account. The amplitude-frequency characteristics of a constant-temperature anemometer with a wire sensor are obtained, and comparisons with the results obtained by a standard method of determining the amplitude-frequency characteristics are performed.

The investigation results on a study of the effect of catalytic oxidation of hydrogen on heat transfer in an impinging jet under chemical activity on the sample surface. It is shown that with an increase in the percentage of hydrogen in the mixture with air, not only an increase in the heat transfer intensity is observed, but also the reaction zone expansion. It is also noted that in the case of a chemically active jet, there are temperature pulsations on the surface (approximately 6%) associated with the reactions of hydrogen catalytic oxidation. At that, the type of dependence of the distribution of the generalized temperature function on the radius on the surface is almost the same for all versions with heterogeneous chemical reactions. An exception is the case with a molar content of hydrogen of 2% in the jet, when there are areas with the value of heat release from reactions below heat transfer during convective heat transfer with a non-reacting flow.

An impact jet with passive control of mixing and heat transfer with the use of a lattice at the entrance is nume-rically studied. It is shown that the local Nusselt number at the stagnation point on the heated surface from which the jet is pushed and the Nusselt number averaged over the domain with intense heat transfer increase with increasing Reynolds number in accordance with a power law corresponding to the empirical approximation. It is found that ad-dition of a lattice, especially fractal lattice, leads to noticeable enhancement of heat transfer in the central part of the jet. The results of the study are compared with effects predicted by computations, and the prospects of further investigations are determined.

Optical diagnostics of the three-dimensional structure of large eddies in the near zone of a turbulent jet (at Re = 5000) exhausting from a round nozzle is performed in the case with coaxial periodic perturbations of the flow through annular slots at the nozzle edge and through holes in the internal surface of the nozzle in the transverse dierection. The external action leads to rapid turbulization of the flow near the nozzle edge due to generation of large extended toroidal vortices in the case of coaxial pertuebations and also due to significant reconstruction of the flow with rapid disintegration of the jet core in the case of transverse perturbations.

The accurate study of heat transfer between water and steam at high pressures was achieved on a developed and tested model of a miixing unit for heat transfer flows (MUHTF). The testing results demostrated that the input water subheating up to the saturation temperature at the model exit is less than 1 and 2 °С for two- and single-tray arrangement of the water-separation unit in the model, correspondingly. The droplet flow model might be applied for thermal calculation of the heating block in the MUHTF.

The paper presents the results of numerical simulation for a near-wall film cooling with gas ejection though a nozzle shaped as a cavity with triangular cross-section (with arranged recess). The flow downstream the recess induces the main flow detachment and generates the coherent vortex structures with a constant frequency of shed vortex (in the zone of mixing with the coolant jet). These vortex structures interact with the wall and improve the coolant spreading in the horizontal direction. This also facilitates the jet flow leaning to the surface at high injection numbers. The cavity’s triangular shape facilitates the lower generation of streamwise vortices that separate the nearwall stream from the surface. The study was conducted for a wide range of coolant injection number. The wall boundary conditions are adiabatic. We determined the injection parameters range suitable for practical applications for the described design. The developed system has a separate vortex shedding frequency and the system is sensitive to the external impact at this frequency. Thus, this approach is a candidate for arrangement a real active control system for film cooling.

The object of this study is a straight rivulet flowing over an inclined plate whose surface is covered with regular nonlinear waves. Such waves can be modeled in full three-dimensional statement, but it is also possible to use a simplified quasi-two-dimensional approach with self-similar shape of rivulet cross-section. In this study we directly compare the results of two- and three-dimensional approaches, where the shape of the wave rivulet surface is reconstructed experimentally using the laser-induced fluorescence technique. It is shown that the three-dimensional model reproduces well the wave surface of a rivulet, including such three-dimensional peculiarities as the wave front curvature and minor perturbations of its rear slope. Though the two-dimensional model is unable to reproduce such peculiarities, it describes well the parameters and shape of a wave in the central longitudinal cross-section of the rivulet.

Under certain conditions, the turbulent transition can produce local turbulent structures knows as puffs. Puffs are the zones of turbulence surrounded by laminar flow; their behavior depends mainly on the Reynolds number (Re). We studied he influence of initial flow conditions on generation of puffs in circular tubes with different lengths using the direct numerical simulation (DNS) approach at a fixed Reynolds number Re ≃ 2200. The literature data show that in the flow with Re ≃ 2000 the single-out puffs are generated as metastable structures with option of decay or survival, while at Re > 2300 these puffs can interact and produce more complicated and stable configurations (double and triple puffs). Puffs are classified as stable puffs if the lifetime exceeds considerably the characteristic time in the system (typically defined as the flow area length divided by the value of axial velocity in a laminar flow interval). The literature data evidences an increase in the amount of puffs with increase in the Reynolds number, but the problem of flow structure reproducibility at the same Reynolds remains an open issue. The published data are important for prognosis and control of turbulence in various engineering application.