bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of relative concentrations in two-component mixtures with unknown composition by laser-induced fluorescence spectra
Authors: Tsibulskaya E O , Maslov N A 
Published: December 2019

Abstract
The paper is devoted to the development of a new methodology of statistical analysis of laser-induced fluorescence excitation-emission matrices. The method allows one to calculate the number of fluorescent components, their excitation and fluorescence spectra in samples under study without using any prior information about their nature. The algorithm is based on the principal component method and is modified for analysis of excitation-emission matrices. Its features were tested on two-component optical phantoms, namely, optically thin mixtures of fluorescent dyes (pyridoxine and fluorescein). The calculated excitation and fluorescence spectra of components coincided with the initial ones with good accuracy (deviation less than 5% in intensity). The weight coefficients proportional to concentrations were calculated by the new algorithm. The comparison of its ratios with those calculated from known concentrations also showed good agreement (deviation of 5%).
Numerical modelling of plasmachemistry induced by cold atmospheric plasma jet near surface
Authors: Vagapov S , Schweigert I V 
Published: December 2019

Abstract
Recently the cold plasma jets are widely used for the development of anticancer therapy. The main mechanism of atmospheric plasma jet action on cells is related to the production of nitrogen and oxygen radicals in plasma-stimulated chemical reactions, followed by the diffusion of radicals into the media with cells. The increase of the plasma jet treatment efficiency depends on a detailed study of the plasma-chemical processes that occur when the plasma jet interacts with the target. In this work, a numerical study of the plasma-chemical processes for dry air is carried out, the main ways of production and loss of RONS are detected and mixture composition near the surface during plasma jet processing is estimated.
Mathematical model of gas mixture adsorption by a composite adsorbent
Authors: Vereshchagin A S , Zinovyev V N , Kazanin I V , Pak A Yu , Lebiga V A , Fomin V M 
Published: December 2019

Abstract
Within a framework of mechanics of multiphase media a mathematical model of the dynamics of a helium and water vapor mixture flowing through a bed of composite adsorbent, based on microspheres and aluminum oxide, is derived. It is shown how to coincide the flow in porous media of adsorber and gas diffusion in a cylindrical granule of adsorbent taking into account helium adsorption by microspheres and water vapor by a porous surface of an adsorbent.
Influence of post-processing on the strength of heterogeneous materials produced by the laser welding
Authors: Vitoshkin I E , Malikov A G , Orishich A M , Karpov E V 
Published: December 2019

Abstract
The paper presents the investigation of the laser welding of the alloy Al-Cu-Li and titanium alloy Ti-Al-V, as well as the analysis of the post=processing on the strength properties of welded joints. Macro- and micro-structure of the joints have been studied. The resulting heterogeneous welded materials have been post-processed. The mechanical characteristics of the welded joints have been determined before and after the thermal processing.
Spherically symmetric stationary flows of a gas suspension
Authors: Voronin S M , Panov A V , Turov M M 
Published: December 2019

Abstract
The dynamics of an isothermal gas suspension is studied. A spherically symmetric stationary submodel is derived and partially integrated. In a barochronous case, this submodel is fully integrated and results are discussed. Different modes of motion are analytically described in the barochronous case. The interpretation of the solutions is proposed. We highlight three essentially different modes of motion. In the first mode, we have a dispersion of gas suspension from the origin with a relaxation of velocities and leading to the uniform motion. In the second mode, phases focus in the origin with finite nonzero velocities and infinitely increasing densities. In the third mode, phases are interpenetrating to each other and decelerating due to the friction force, that leads to an accumulation of particles and an unlimited increase of densities in different nonzero raduises with zero velocities.
Numerical simulation of the cellular detonation interaction with inert gas plugs
Authors: Bedarev I A 
Published: December 2019

Abstract
The mathematical modeling of the interaction of a cellular detonation wave propagating through a hydrogen-air mixture with inert gas plugs is performed. A technology for calculating two-dimensional detonation flows in a reacting gas mixture - non-reacting gas system has been developed. The modes of cellular detonation waves interaction with inert gas plugs were studied. The geometric limits of the clouds of carbon dioxide, argon and nitrogen lead to the cellular detonation failure and isolation of the combustion zone are determined.
Combustion of round hydrogen microjet in a concurrent flow
Authors: Kozlov V V , Grek G R , Litvinenko M V , Litvinenko Yu A , Tambovtsev A S , Shmakov A G 
Published: December 2019

Abstract
Experimental data on the diffusion combustion of round hydrogen microjet in concurrent coaxial flows are presented. The effects on combustion of the concurrent flow of air and that of air premixed with nanopowder of TiO2 are of interest. The hydrogen microjet is emanated from a round micronozzle which is surrounded by a coaxial slit to produce the concurrent flow. Combustion events found in the present conditions are similar to those observed in the previous studies on diffusion combustion of hydrogen microjets at subsonic and supersonic velocities. In a subsonic range, the so-called “bottleneck-flame region” is generated close to the nozzle exit, while in high-speed conditions the flame separates from the nozzle. At increasing velocity of both the hydrogen microjet and the concurrent flow, the “bottleneck-flame region” is still found and the combustion becomes more intense. The “bottleneck-flame region” is suppressed at the microjet velocity approaching transonic values.
Effect of a smooth temperature gradient on the combustion of a preliminary mixed methane-air mixture
Authors: Ponomareva A A , Mokrin S N , Uriupin G V , Minaev S S 
Published: December 2019

Abstract
In this work, the ranges of different combustion modes of a methane-air mixture were studied in dependence on the flow velocity under conditions of a smooth temperature gradient of the channel. To carry out the experiments, a laboratory setup was designed and constructed to obtain a smooth temperature gradient in a quartz tube, and experiments were performed to determine the temperature gradient. The boundaries of different combustion regimes were determined for the mixtures with different fuel-air ratio coefficients (0.8, 1, 1.2), moreover, transient modes between main regimes were found.
Three-dimensional numerical simulation of continuous spin detonation in hydrogen-oxygen and hydrogen-air mixtures using OpenFOAM package
Authors: Rybnikov A I , Simonov E V , Gurin A M , Trilis A V , Samsonov A N 
Published: December 2019

Abstract
A mathematical model of continuous spin detonation for hydrogen-oxygen and hydrogen-air mixtures is developed within the framework of a nonstationary gas-dynamic formulation. An OpenFOAM package is used to carry out numerical calculations in an annular cylindrical combustor in order to compare the main solution parameters with experimental data for geometric dimensions of combustors 40 mm and 306 mm in diameter corresponding to the experiments for hydrogen-oxygen and hydrogen-air mixtures. Regimes with a single continuously rotating transversal detonation wave are obtained for given fuel mixtures. It is shown that the solution significantly depends on the coordinate along the radius. The results for the hydrogen-oxygen mixture are in good agreement with an experiment in terms of a wave velocity and satisfactory agreement relative to a front height and the number of waves (a 1.5- to 2-fold difference). The results for the hydrogen-air mixture are in satisfactory agreement with an experiment for the wave velocity and front height and significantly differ from it on a minimal flow rate of the mixture, in which the existence of continuous spin detonation is possible in the combustor.
Experimental study of the low-melting hydrocarbons regression rate in the inert gas flow
Authors: Shiplyuk A N , Zvegintsev V I , Frolov S M , Vnuchkov D A , Lukashevich S V , Nalivaychenko D G 
Published: December 2019

Abstract
Gasification of organic and inorganic materials in a high-temperature gas flow is a promising technology for various industrial applications like chemical industry, waste processing, rocket and air-breathing propulsion, etc. However, the characteristics of the gasification process of low-melting hydrocarbon materials remain insufficiently studied so far. The present authors propose a methodology for investigating the gasification of combustible materials for ramjets. Experiments on the gasification of cylindrical polypropylene (PP) samples by the high-temperature inert carrier gas (nitrogen) passing through multiple longitudinal channels of 3 mm in diameter and 200 mm long are performed. The flow of the carrier gas is heated by combustion of hydrogen–oxygen mixture. The temperature, pressure, and velocity of the carrier gas in the experiments range from 900 to 1700 K, 0.35 to 1.0 MPa, and 80 to 130 m/s, respectively. The yield of PP gasification products is shown to increase linearly with the carrier gas temperature. At the temperature of 1700 K, the yield of PP gasification products in the test facility attains 8.0 g/s, whereas the ratio of the mass flow rates of the carrier gas and gasification products reaches the value of 4.5.
Flame stretching by electric field
Authors: Tupikin A V , Zamashchikov V V 
Published: December 2019

Abstract
The paper considers the issues related to the study of the mechanisms of controlling the combustion of hydrocarbon fuels by electric fields. It is shown that influence of weak electric field on combustion in laminar mode leads to a change in the degree of flame stretching (Karlovitz number). For the Bunsen flame and reversed flame, estimates of changes in values of the degree of flame stretching when imposing an external constant electric field on flame are made.
Study of the possibility of steady horizontal flight of the dual aircraft platform with the wind shear
Authors: Akimov A M , Polivanov P A 
Published: December 2019

Abstract
In the first part of paper accurate and approximate solution for the equation of motion of steady horizontal flight for dual-aircraft platform (DAP) was given. The two gliders (sailplanes) fly at different heights and connected by a tether. To perform a horizontal flight only the effect of wind shear is used. Minimum of platform velocity to cross wind shear ratio was founded. In the second part of paper overview airflow for troposphere and stratosphere of Earth was given. Wind velocity profile was investigated for some random places. Opportunity of flight without engine was approved. However it is possible at specific conditional only.
Flow features in a hypersonic module with a compact cross-section
Authors: Akinin S A , Starov A V 
Published: December 2019

Abstract
A model of a hypersonic air intake based on the principle of compression along the directions of the captured jet converging in space is studied. Such an air intake allows a high compression ratio and a compact section of the internal channel, which simplifies the heat protection of the air intake and the combustion chamber. Experimental studies were carried out in a pulsed wind tunnel IT-302M for Mach number M = 6 - 8 in the range of angles of attack from 0° to 8°. Numerical simulation has been performed based on solving the full averaged Navier-Stokes equations, supplemented k-w turbulence model. The pressure distributions on the compression surfaces and in the air intake channel are obtained, the coefficients of the total pressure recovery and flow rate, the Mach number in the throat of the air intake are determined. The features of the flow structure for three variants of the air intake in the area of external compression are established: with side walls, side walls with slots and without side walls. The influence of the boundary layer bleed and lateral spreading on the launch and integral characteristics of a hypersonic air intake with a compact cross-section of the inner channel is determined. Satisfactory agreement between the calculated and experimental data is shown.
Influence of surface sublimation on boundary layer stability at high Mach number
Authors: Gaponov S A , Semenov A N , Smorodsky B V 
Published: December 2019

Abstract
Results of theoretical investigation of the linear stability properties of Mach 6 boundary layer on a flat-plate with sublimation coating are presented. Naphthalene (C
10
H
8) was chosen as a substance for such a coating. This is an organic compound capable to pure sublimation (phase transition from the solid state directly to gas, bypassing the melting stage) at moderate temperatures. Calculations performed on the basis of binary-mixture boundary-layer equations in the approximation of local self-similarity revealed that with increasing flow stagnation temperature the adiabatic surface temperature also increases that causes growth of mass flow rate of naphthalene evaporation. This leads to an increase in the density of the binary mixture (air and sublimation vapors) near the wall. The performed linear stability computations show that such a modification of the boundary layer profiles causes a reduction in the local linear amplification rates of perturbations of the first mode, while disturbances of the second mode are destabilized by the surface sublimation.
Effect of stationary longitudinal structures on the growth of Tollmin-Schlichting waves
Authors: Gaponov S A , Terehkova N M 
Published: December 2019

Abstract
The paper considers the possibility of increasing of the nonstationary wave (similar to Tollmin-Schlichting (T-S) wave) growth by striped stationary structures of eigen-problem of stability of the supersonic boundary layer stability. The problem is solved within the framework of three-wave resonance interaction in local-parallel approximation. In this work the pumping wave is the stationary almost striped structures. Studies have shown that even in a stable area under the influence of longitudinal structures there is an increase of T-S waves. At sufficiently high amplitudes of stationary perturbations their effect on T-W waves is noticeable even in unstable area.
The influence of dual stream jet nozzle internal parts on the three-dimensional flow structure in a supersonic jet
Authors: Kiselev N P , Zapryagaev V I , Kundasev S G 
Published: December 2019

Abstract
The work is devoted to the experimental study of a high-speed jet exhausting from a model dual stream jet nozzle, performed using non-contact (shadow visualization) and probe (total-pressure pneumatic receiver) methods for measuring gasdynamic quantities. Azimuthal non-uniformity of the pressure distribution, whose value in the external duct is much higher than that in the internal duct, is revealed. The cause for the formation of the spatial flow structure is related to the supporting pylons inside the nozzle contour and to the occurrence of a transonic flow regime in the external duct.
Effect of a uncertainties of flow parameters on the separation zone at supersonic speeds
Authors: Kutepova A I , Polivanov P A , Sidorenko A A 
Published: December 2019

Abstract
The CFD calculations were performed basing on RANS approach with the Menter transition model [1]. The shock wave / boundary layer interaction (SWBLI) developed on a flat plate was considered. The oblique incident shock wave was generated by a wedge which was placed over the plate. The sensitivity of the separation zone to various inflow and geometrics parameters was studied. Verification of the calculations was carried out on the basis of experiments performed in the T-325 wind tunnel [2] for an angle of attack of wedge β = 4°.
Investigation of jets mixing in the channel of the hypersonic rocket-ramjet engine model
Authors: Lokotko A V 
Published: December 2019

Abstract
A technique of investigating jet mixing in the channel of a rocket-ramjet engine model in the conditions of an external supersonic airflow is proposed. Rocket exhaust jets are modeled with heated high-pressure air. Numerical computation of the mixing ratio (V. I. Kopchenov, Central Institute of Aviation Motors (CIAM)) yielded satisfactory qualitative agreement with the experimental results.
Influence of individual roughnesses nozzle edge on the length of the supersonic section of an underexpanded microjet
Authors: Mironov S G , Aniskin V M 
Published: December 2019

Abstract
The paper presents the results of the experimental investigation of the influence of a small group of roughnesses uniformly located on the edge of the convergent nozzle on the length of the supersonic core of an underexpanded air microjet. The tests are carried out on the low-pressure test bench with the aid of the Pitot tube. The set of nozzles with the diameter of 2 mm, with the smooth output edge and the edge of the similar shape roughnesses (from 2 to 4) is used. The underexpanded microjets flowing out from the nozzles of the diameter 10.6; 16.1; 21.4, and 34.8 μm are simulated by the outflow Reynolds number. It is shown that the presence of roughnesses can reduce essentially the supersonic section length and eliminate the previously found effect of microjet “relaminarization”, however the reduction value dubiously depends on the amount of the roughnesses on the nozzle edge.
Stability of the laminar boundary layer on the surface of the Mach-6 contoured nozzle
Authors: Morozov S O , Shiplyuk A N 
Published: December 2019

Abstract
The stability of the laminar boundary layer on the surface of the Mach 6 contoured nozzle designed for short-duration wind tunnel Transit-M is investigated. The numerical simulation of the laminar flow inside the nozzle is performed using Ansys Fluent software. The obtained boundary layers profiles on the nozzle surface are used to calculate the growth rate of the first and second Mack mode and Görtler vortices in the framework of the linear stability theory. It has been shown that, for the Mach 6 nozzle, the Görtler vortices grow most rapidly, the first Mack mode grows slower, and the second mode is insignificant.
Gas-dynamic factors controlling the level of the sonic boom generated by two bodies in a supersonic flow
Authors: Moskvichev D Yu , Potapkin A V 
Published: December 2019

Abstract
The results of calculation of the sonic boom generated in a supersonic air flow by two bodies (disk and slender body of revolution) are presented. The bodies are arranged one behind the other. The slender body is aerodynamically shaded by the disk. The free-stream Mach number is 2. The calculations are performed by a combined “phantom bodies” method. The sonic boom level can be reduced by more than 12% via the disk position and size changing, as compared to the sonic boom generated by the slender body. the gas-dynamic factors affecting the sonic boom level are described on the base of the calculation results.
Determination of the heat transfer coefficient during the leakage of a subsonic axisymmetric air mini jet onto a plate
Authors: Mukhin K A , Aniskin V M , Maslov N A 
Published: December 2019

Abstract
In the present article, the heat transfer coefficient was determined experimentally when a subsonic jet flows onto a plate. The jet escaped from axisymmetric nozzles with a diameter of d = 290, 540, and 980 μm. The experiments were carried out at the speeds of V = 5, 20, 40, 60, 80 and 100 m/s in the Reynolds numbers range of 100 – 7000. The Nusselt number distribution was obtained for different distances between the nozzle and cooled surface.
The controlled periodic impact on the longitudinal vortex in the boundary layer at Mach 2
Authors: Piterimova M V , Kosinov A D , Panina A V , Semionov N V , Ermolaev Yu G , Yatskikh A A 
Published: December 2019

Abstract
Experimental data on the development of controlled disturbances in the boundary layer with a longitudinal vortex are analysed. It is found experimentally that the mean flow nonuniformity can vary from 0.7 to 0.9 V in terms of the CTA mean voltage or 30–40% in ρU. Such flow nonuniformity complicates the estimation of the wave spectra, where normalization on the mean voltage of the anemometer is required. The applicability of the standard processing procedure is investigated. Comparative analysis of the data shows that both normalization types considered in the work can be applicable. However, in the case of flow nonuniformity in the transverse direction, it is preferable to use the normalization on the median value over the mean voltage spanwise distribution.
Studying of the resonator depth influence on amplitude-frequency characteristics operating flow in the two-channel system
Authors: Primakov A V , Zhilin A A 
Published: December 2019

Abstract
This paper is devoted to an experimental study of the characteristics of the operating flow in a two-channel system of an acoustic-convective dryer (ACD), developed at the Institute of Theoretical and Applied Mechanics (ITAM) SB RAS. A parametric study of cylindrical resonator depth and pressure in settling chamber influence on amplitude-frequency characteristics (AFC) of the formed flow is carried out. The influence of pressure in settling chamber and geometry of resonant cavity on AFC are considered. A tendency toward a decrease in Hartmann effect existence region with a decrease in cavity depth was found. A satisfactory agreement was obtained between the frequencies registered in the experiments and calculated using the Helmholtz formula for the natural frequency of resonant cavity.
Experimental study of the laminar-turbulent transition on models of wings with subsonic and supersonic leading edge at M = 2
Authors: Semionov N V , Yermolaev Yu G , Kosinov A D , Kocharin V L , Panina A V , Semenov A N , Shipul S A , Yatskikh A A 
Published: December 2019

Abstract
The paper is devoted to an experimental study of laminar-turbulent transition in supersonic boundary layers on swept wings at Mach 2. The experiments were fulfilled in the low nose supersonic wind tunnel T-325 of Khristianovich Institute of Theoretical and Applied Mechanics on the models with supersonic or subsonic leading edges. The transition location was determined using a constant temperature hot-wire anemometer. while experiments for the case of a supersonic leading edge are a continuation of previous studies, then for the case of a subsonic leading edge, the first data have been obtained that show the possibility of carrying out studies on the development of unstable perturbations. It was obtained that transition take place parallel to the leading edge for both models. The destabilizing effect of the surface curvature of the model on the position of the laminar-turbulent transition for the case of a supersonic leading edge was confirmed. This experimental data is the room for further investigation.