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(Mach rings) [ ] - stationary repeating wave formations in a supersonic jet of gases emanating from nozzles of turbojet, ramjet and rocket engines. Mach discs become visible when fuel is burned outside the engine. In a turbojet engine, this is possible when the afterburner is turned on.

Formation mechanism

Mach disks are formed in a supersonic jet of outgoing gases, the pressure of which at the nozzle exit is slightly higher or lower than atmospheric. At the exit from the nozzle, atmospheric pressure expands / compresses the underexpanded / overexpanded gas jet, which leads to a change in the direction of movement of the outer gas layers from axial to radial. The change in the direction of the supersonic gas flow occurs on oblique shock waves. Where the direction of gas flow again becomes parallel to the centerline of the flow, the first direct shock wave is located. A jet of gases passing through a direct compression shock heats up and ignites the unburned fuel, making the first Mach disk visible. The glowing area can be in the form of a disc or a diamond. The distance from the nozzle exit to the first Mach disk can be approximately determined using the following formula:

x \u003d 0.67 D 0 P 0 P 1 (\\ displaystyle x \u003d 0.67D_ (0) (\\ sqrt (\\ frac (P_ (0)) (P_ (1))))),

where D 0 is the nozzle exit diameter,

P 0 - flow pressure at the nozzle exit,

When passing through a direct jump in compression in the Mach disk, the gas pressure can rise above atmospheric. Then the expansion process is repeated with the final formation of the next Mach disk. This periodic compression / expansion process would be infinite were it not for the influence of gas viscosity on damping pressure fluctuations.

Formations in a supersonic jet of gases emanating from nozzles of turbojet, ramjet and rocket engines. Mach discs become visible when fuel is burned outside the engine. In a turbojet engine, this is possible when the afterburner is turned on.

Formation mechanism

Mach disks are formed in a supersonic jet of outgoing gases, the pressure of which at the nozzle exit is slightly more or less than atmospheric. At the exit from the nozzle, atmospheric pressure expands / compresses the underexpanded / overexpanded gas jet, which leads to a change in the direction of movement of the outer gas layers from axial to radial. The change in the direction of the supersonic gas flow occurs on oblique shock waves. Where the direction of gas flow again becomes parallel to the centerline of the flow, the first direct shock wave is located. A jet of gases passing through a direct compression shock heats up and ignites unburned fuel, making the first Mach disk visible. The glowing area can be in the form of a disc or a diamond. The distance from the nozzle exit to the first Mach disk can be approximately determined using the following formula:

x \u003d 0.67 D 0 P 0 P 1 (\\ displaystyle x \u003d 0.67D_ (0) (\\ sqrt (\\ frac (P_ (0)) (P_ (1))))),

where D 0 is the nozzle exit diameter,

P 0 - flow pressure at the nozzle exit,

The supersonic jet has a periodic structure consisting of repeating barrel-shaped cells. If the jet off-design, which is defined as the ratio of the pressure at the exit of the supersonic nozzle to the pressure in the environment, differs significantly from unity, then in the shock-wave structure of the jet, direct shock waves become clearly visible, which are called Mach disks. The Mach disk has significant dimensions only in the first barrel of the jet and sometimes in the second. However, its presence strongly affects the downstream jet geometry. Failures in constructing methods for calculating jets, as a rule, are largely associated with the inability to find the position of the Mach disk. On the other hand, the flow in the vicinity of the Mach disk is distinguished by large pressure gradients and strong viscous-inviscid interaction. Combustion and dissociation reactions occur in the jets of rocket engines in the regions behind the Mach discs, which leads to a significant increase in temperature, pressure, and radiant flux. Despite the practical importance of the problem, a complete theory of the formation of a Mach disk in a supersonic jet is still lacking. The necessary information on triple configurations of shock waves is presented below, a description of the "stationary Mach configuration" model is given, as well as the justification for its application to the problem of calculating the Mach disk in a supersonic jet of ideal gas.

triple point.

triple shock wave configuration

stationary Mach configuration

irregular jump reflection

regular jump reflection

mach leg

mach disk

1. Gas dynamics of supersonic nonisobaric jets / V.S. Avduevsky, E.A. Ashratov, A.V. Ivanov, U.G. Pirumov. - M .: Mashinostroenie, 1989 .-- 320 p.

2. Belyaev N.M., Karteshkin V.A. Investigation of the parameters of a sonic underexpanded cold gas jet. - Dnepropetrovsk: DGU, 1982 .-- 14 p.

3. Bulat P.V., Zasukhin O.N., Uskov V.N. Formation of a jet at a smooth start of the Laval nozzle // Gas dynamics and heat exchange. Issue 10. Gas flows in channels and jets. - SPb .: Publishing house of SPU, 1993. - S. 1-22.

4. Melnikov D.A. Reflection of shock waves from the axis of symmetry // Mechanics and mechanical engineering. - 1962. - No. 3. Ed. Academy of Sciences of the USSR.

5. Interference of stationary gas-dynamic ruptures / V.N. Uskov et al. - Novosibirsk: VO "Science", 1995. - 180 p.

6. Uskov V.N. Interference of stationary gas-dynamic discontinuities. Supersonic gas jets. - Novosibirsk: Nauka, 1983 .-- S. 82-96.

7. Abbett M.J., Mach Disk in Underexpanded Exhaust Plumes // AIAA Journal. - 1971. - Vol.9, March. - R. 512-514.

8. Dash S.M. Seiner J.M., Wolf D.E. Analysis of Turbulent underexpended Jets. Part. 1: Parabolized Navier Stokes Model, SCIPVIS // AIAA J. - 1985. - vol. 23, 23, April. - R. 505-514.

9. Dash S.M. Seiner J.M., Wolf D.E. Analysis of Turbulent underexpended Jets. Part. 2: Parabolized Navier Stokes Model, SCIPVIS // AIAA J. - 1985. - vol. 23, 23, May.

10. Dash S.M. Thorpe R.D. Shock - Capturing Model of One- and Two-Phase Supersonic Exhaust Flow // AIAA J. - July 1981. - vol. 19. - R. 842-851.

11. Dash S.M., Sinha N. Noninteractive Cross - Flow integration Procedure for the Pressure - Split Analysis of two Dimensional, Subsonic Mixin Problems // AIAA J. - 1985. - vol. 23, Jan. - R. 183-185.

12. Dash S.M., Sinha N., York B.J. Implicit / Explicit Analysis of Interactive Phenomena in Supersonic Chemically - Reaching Mixing and Boundary Layer Problems // AIAA paper 8517, 17 July 1985.

13. Dash S.M., Wolf D.E. Interactiv Phenomen in Supersonic Jet Mixin Problems, Part. 1. - AIAA J. - May 1984. - P. 905-913.

14. Dash S.M., Wolf D.E., Pergament H.S. A Chock-Capturing Model for Two - Phase, Chemically reaching Flow in Rocket Nozzles and Diffusers, - AIAA P. 85-0.

15. Jungowski W.M. On flow in suddelargement of a duct. Fluid dynamic. - 1969. - vol. 4. - P. 231-241.

Supersonic jet (fig. 1) in the general case of an outflow from a nozzle of an aircraft moving at a certain speed, it is a set of shock waves, surfaces of tangential discontinuities of velocity, and regions of smooth flow. The presence of bottom rarefaction in region 1, compression waves 3, 7 arising from the interaction of the jet with a supersonic cocurrent flow 2, mixing layers 4, 9, 10, formed at tangential discontinuities, lead to the formation of a complex shock-wave structure (SWS) of the jet. It consists of rarefaction waves 4, 6 and shock waves. The incident shock 5 is always reflected from the axis with the formation of a triple configuration of shock waves or, as they say, a triple point. The direct shock at the triple point is called the Mach disk or the Mach disk, and the shock 8 is the reflected one.

It should be noted that as the incident shock approaches the axis of symmetry, its curvature TO σ tends to infinity, because TO σ ~ y -1; therefore, conditions for the formation of a flywheel disk in the off-design jet are always created. This fact corresponds to the one known from the works of D.A. Melnikov. (1962) on the impossibility of regular reflection of the shock wave from the axis of symmetry, which is also indicated by dynamic compatibility conditions(UDS) on shock waves... On the axis of symmetry, the conditions of equality to zero of the angle of inclination of the velocity vector and the curvature of the streamline behind the reflected shock must be satisfied, but at y\u003d 0 this is impossible.

Figure: 1. Supersonic flow around the bottom of the aircraft: 1 - bottom area; 2 - cocurrent flow; 3 - tail shock; 4 - dividing line of current; 5 - hanging jump; 6 - subsonic region of the mixing layer; 7 - compression waves and a closing shock; 8 - reflected jump; 9 - mixing area behind the Mach disk; 10 - mixing layer at the jet boundary

Mach disc formation models - a history of the study

Let us dwell in more detail on the question of the position of the Mach disk in the jet. The Mach disc is noticeable only in the first barrel and sometimes in the second. However, its presence strongly affects the downstream jet geometry.

Failures in constructing methods for calculating jets, as a rule, are largely associated with the inability to find the position of the Mach disk. A detailed analysis of this issue is carried out in, where various hypotheses available in the literature on the transition from the regular reflection of the shock wave from the axis to the irregular (Mach) one are discussed. The most famous of them is the so-called Abbet procedure, which was often mentioned in Dash's famous works devoted to the construction of a method for calculating the torch of a solid-propellant tactical rocket engine, as well as various assumptions about the magnitude of the pressure behind the reflected shock at the triple point. We will not consider the latter, since it is already known today that they are not generally applicable.

Abbet's procedure establishes some analogy between a Mach disk in a jet and a launching shock wave (PUW) that occurs when a Laval nozzle is launched. Initially, it was assumed that the pressure in the minimum flow section behind the Mach disk is equal to atmospheric pressure. Later it turned out that this assumption is approximately fulfilled only in strongly underexpanded jets, in which a turbulent section begins immediately after the first barrel. In sparsely calculated jets, Abbet's hypothesis leads to too large errors.

Abbet's hypothesis was modernized by Dash, assuming that in the critical section behind the Mach disk, the “flow throat” condition is satisfied; the speed of the current becomes equal to the local speed of sound. If the position of the triple point is specified on the falling shock, then the initial conditions for calculating the flow bounded by the Mach disk and tangential discontinuity are determined. Considering this flow to be one-dimensional, one can perform the calculation in the same way as in the Laval nozzle. If, as a result of the calculation in the minimum flow section behind the Mach disk, the velocity is equal to the local speed of sound, then in the Abbet-Dash procedure it is assumed that the position of the Mach disk in the jet is chosen correctly.

Among other models, the experimentally described criterion, according to which the formation of a Mach disk occurs when the intensity of the incident jump reaches the value J \u003d J 0 corresponding stationary Mach configuration(QMS) . Such configurations of shock waves have been studied in detail in connection with the problem of reflection of a shock wave from a solid wall.
An indirect substantiation of the J 0 criterion is the solution of the first order problem on triple configurations of shock waves (jumps). If a formal calculation of the triple configuration of shock waves is performed at each point of the hanging shock (incident on the axis of symmetry), then at intensities J< J 0, the outgoing tangential discontinuity τ has a positive curvature. At the jump point where J \u003d J 0, the curvature τ becomes negative, which corresponds to the established empirical ideas about the shape of the tangential discontinuity.

Brief information on the theory of triple jump configurations

The triple configuration (TC) of shock waves (shocks) is called a shock-wave structure consisting of three shock fronts σ intersecting on a certain line and a tangential discontinuity surface τ emanating from this line (Fig. 2), σ 1 is called an incoming shock, σ 2 - outgoing, σ from - the main shock.

Figure: 2. Triple configuration of shock waves

Triple configuration occur in the case of irregular reflection of a shock from a solid surface and from the axis of symmetry in axisymmetric flows, in some problems of the interaction of counterpropagating shocks, as well as in the interaction of overtaking shocks. For the first time, the concept of TC was introduced in the problem of a shock wave running on a wedge. As it propagates along the wedge, the incident wave intensity increases, and its surface is curved, remaining perpendicular to the wedge surface. Starting from a certain moment, the shock wave branches out to form mach legs.

Later, the stationary case of shock reflection from a solid wall was studied. When the intensity of the shock incident on the wall is low, it is reflected from the wall in a regular manner (Fig. 3). Starting from a certain intensity, the reflected shock can no longer turn the flow in such a way that the velocity vector behind it is parallel to the wall, because the limiting angle of flow turn at the shock, calculated from the Mach number behind the first shock, is less than the angle of inclination of the velocity vector to the wall surface behind the first shock. Then the reflection occurs irregularly with the formation of SMC. In contrast to the nonstationary case, the intensity of the Mach leg is equal to the maximum J m (M).

It is convenient to study ternary configurations on the plane of shock polar lnJ-β , nicknamed for their characteristic appearance heart-shaped curves. A detailed analysis of heart-shaped curves, singular points, regions of existence of TCs is given in. The classification distinguishes between triple configurations TK-1, TK-2 and TK-3.

Figure: 3. Regular (left) and irregular (right) shock reflection from the wall: σ from - mach leg

Triple configurations TK-1 arise from the interaction of opposing shock waves of different directions, for example, in supersonic air intakes of internal compression. ТК-1 corresponds to the point of intersection of the left branches of the polar (Fig. 4). As the intensity of the incoming shock 1 increases, the intersection point moves towards the top of the main polar until it reaches it; this moment corresponds to the SMC.

TK-1 can only exist with Mach numbers M\u003e M T

At lower Mach numbers, the polars do not intersect. With a Mach number equal to M T, behind the jump, the maximum static pressure is reached at a given adiabatic exponent γ (for air γ \u003d 1.4). Triple configurations TK-2 occur when the shock wave is irregularly reflected from the wall. The difference from TK-1 is that in TK-2 the direction of flow deflection at the main shock (Mach stem) is reversed (Fig. 5). As the intensity of the jump increases J 1 main jump 4 is bent. When shock 1 is reflected from the wall, the Mach leg is bent, approaching the wall orthogonally.

Figure: 4. Triple configuration TK-1

Figure: 5. Triple configuration TK-2

Triple configurations TK-3 arise in the interaction of overtaking shock waves of one direction. Their study is of great practical importance for the design of supersonic external compression air intakes. Triple jump configurations and Mach disks in a jet

Let us dwell in more detail on the triple configurations of TK-2, since they are directly related to the problem of calculating the Mach Disk in a supersonic jet. The triple configurations TK-1 and TK-2 are separated by a stationary Mach configuration, which corresponds to the case when the secondary shock polar intersects the main polar at its apex. In the SMC (Fig. 6), the main shock (4) is straight. Characteristic intensity J 0 is obtained from the solution of the cubic equation corresponding to the intersection of the polar at the vertex of the main polar (Fig. 6).

z 0 \u003d J 0 ,

Figure: 6. Stationary Mach configuration (SMC)

For some characteristic Mach number M OR. In the SMC, the polar corresponding to the incoming shock 1 crosses the top of the main polar at the point of the limiting rotation angle 4 (Fig. 7).

Hence follows the transcendental equation for the singular number M 0R:

Odds A i have the same meaning as in the previous equation.

With Mach numbers less than M OR, the polar intersects with the y-axis inside the main polar and often the intensity is taken as a criterion for the transition to irregular reflection J R, which corresponds to the tangency of the polar to the ordinate axis (Fig. 8), which allows finding the value of this intensity from the solution of the following equation:

Figure: 7. Special configuration according to MOR

In the stationary case, this criterion has not received experimental confirmation.

Testing the SMC hypothesis for the case of the formation of a Mach disk in a jet

In order to correctly check the correspondence of the calculation procedure to the experimental data, it is necessary to reduce in the experiment the influence of viscous effects that distort the flow pattern in the vicinity of the nozzle edge to a minimum. This can be achieved in a plant in which the jet flows from a sonic nozzle with a bottom shield. Inside such a nozzle, the boundary layer is small, and there is no ejection flow at its edge.

Figure: 8.TK corresponding to J \u003d JR, M< МOR

A similar experiment was carried out at the Dnepropetrovsk University. In fig. 9 and 10 show the dependences of the removal L from the nozzle exit of the characteristic jet cross-sections, as well as the value of the diameter D of the corresponding element of the first barrel of the jet from the self-similar parameter, obtained by calculation by the method of characteristics.

Figure: 9. Comparison of the removal of the main sections of the first barrel of the underexpanded jet, obtained by calculation, with the experimental data:
L b - distance from the nozzle exit to the point of intersection of the reflected shock with the jet boundary; L ВС - the distance from the nozzle exit to the section with the maximum diameter of the hanging shock; L M - distance from the nozzle exit to the section with the maximum diameter of the jet boundary; L DM - distance from the nozzle exit to the flywheel disk

Figure: 10. Comparison of the results of calculating the diameter of the main elements of the first barrel of the jet with the experiment: D ВС - the maximum diameter of the hanging shock; D M - maximum diameter of the jet boundary; D DM - diameter of the fly disc

The triple point on the hanging shock was chosen in the section in which the intensity of the hanging shock was J 0... Not only qualitative, but also satisfactory quantitative agreement with experiment is observed.

Conclusion

It is shown that the model of a stationary Mach configuration makes it possible to predict well the position of Mach disks in a supersonic jet. When calculating the Mach disk at the point of the hanging shock, at which its intensity J \u003d J 0, you can determine the diameter of the Mach Disc and its distance from the nozzle exit. The calculation results showed good agreement with experiment. The above arguments can only serve as an indirect proof of the model; its theoretical justification and the results of a full computational and experimental study are beyond the scope of this work and will be considered separately.

Reviewers:

Baranov I.V., Doctor of Technical Sciences, Professor, Deputy Director of the Institute of Refrigeration and Biotechnology, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg;

Pelenko V.V., Doctor of Technical Sciences, Professor, Deputy Director for Academic Affairs of the Institute of Cold and Biotechnology, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg.

The work was received on 20.07.2012.

Bibliographic reference

Uskov V.N., Bulat P.V., Prodan N.V. THE HISTORY OF STUDYING THE UNREGULAR REFLECTION OF THE JUMP OF THE SEALING FROM THE SYMMETRY AXIS OF A SUPERSONIC JET WITH THE FORMATION OF A MAX DISK // Fundamental Research. - 2012. - No. 9-2. - S. 414-420;
URL: http://fundamental-research.ru/ru/article/view?id\u003d30239 (date of access: 07/29/2019). We bring to your attention the journals published by the "Academy of Natural Sciences"

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Health-improving and professional-applied efficiency of mass physical culture work in a vocational school dormitory (for example, a building one)

M .: PROMEDIA

Therefore, the obligatory set of simulators for a bricklayer, for example, included "Disk of health", for a plumber-gas-welder

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carriers of magnetic disks.<...> Users and even programmers often say, "Drive A:", "Drive B:", etc.<...> from a disk, for example, to a screen, to another disk, or to a printer.<...> The teacher prepared with this Goal: th disks for each workplace (on each disk Mikron with text<...> The list of names of files stored on a disk is called a disk directory.

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No. 5 [Thermal physics and aeromechanics, 2015]

The flow behind the reflected shock is supersonic, and behind the Mach disk is subsonic.<...> <...>to the Mach disk at rA \u003d 0.35 and rA \u003d 0.26.<...> subsonic flow zones behind the Mach disk.<...>to the Mach disk at rA \u003d 0.35 and rA \u003d 0.26.

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The results of numerical simulation of the leakage of an underexpanded pulsed gas-dispersed jet with a high concentration of particles onto a rigid, transversely unlimited obstacle are presented. The characteristic features of this interaction were studied, in particular, the “anomalous” formation of a shock-wave structure of a two-phase flow at a subsonic velocity in the carrier gas and the development of self-oscillations

Some differences, for example, the calculated size of the Mach disk, are larger than what is observed in the experiment (Fig.<...> In this case, the Mach 1 disk for the case of the initial bulk concentration of particles (Fig. 4) consists of two parts<...> This is due to the vortex motion of mixture 2, which is adjacent to the Mach disk near the axis of symmetry.<...> In the second version, behind the Mach disk x ′ ′ \u003d 6.<...> Then the two-phase medium runs onto the obstacle with the formation of a Mach 4 disk.

A method for correcting the PIV data for reconstructing the gas velocity from the particle velocity in supersonic underexpanded jets is considered. The method is based on the estimation of the velocity retardation of tracers from their velocity relaxation parameter as a correction to the PIV data in the Newtonian approximation of interphase interaction. It is shown that the parameter of velocity relaxation of tracers in flows with velocity jumps can be determined from the initial PIV data. Correction with the found parameter of velocity phase relaxation showed good accuracy.

<...> <...> <...> <...>

The problem of initiation and stabilization of detonation combustion of a hydrogen-air mixture entering an axisymmetric channel with a central body of finite length in a flow with a Mach number M0 \u003d 5–9 is solved. It is numerically shown that the presence of a central body both in a convergent-divergent nozzle and in an expanding channel provides stabilization of detonation combustion of a stoichiometric hydrogen-air mixture at the freestream Mach numbers M0\u003e 7. Comparison of various channel configurations is carried out depending on the thrust resulting from detonation combustion of a stoichiometric hydrogen-air mixture

of the central body, when a high-speed supersonic flow flows into it, a disk is formed near the axis of symmetry<...> hydrogen-air mixture obtained for a nozzle with an inner cylinder, the presence of which prevents the formation of a disk<...> Thus, in an axisymmetric convergent divergent nozzle without a central body, a disk is formed in the flow<...> the flow of the flammable mixture begins to interact with the central body as behind the point of disc formation<...>Mach, and in front of it (Fig. 4).

The paper presents the results of investigating the leakage of a supersonic underexpanded air jet onto a porous metal barrier of finite thickness, the front plane of which is perpendicular to the jet axis, and the side surface is impermeable to the gas flow. To determine the effect of porosity on the gas-dynamic characteristics of the interaction of a jet with an obstacle, the case of a non-porous obstacle of the same diameter was also considered.

The Mach number in the outlet section is Ma \u003d 1.72, the degree of off-design of the jet outflow is n \u003d 2.1.<...> A porous barrier in the form of a disk with a diameter of dp \u003d 100 mm and a thickness of ∆lp \u003d 20 mm was inserted into a metal<...> Supersonic underexpanded jet interacting with a porous obstacle: a is the minimum distance between the disk<...> The vibration amplitude of the Mach disk along the jet axis is 0.15da.<...> T. 56, N-◦ 3 corresponded to the rotation of the flow through an angle equal to 90◦, while the Mach disk was at the relative

No. 1 [Thermal physics and aeromechanics, 2018]

Founders of the journal: Siberian Branch of the Russian Academy of Sciences Institute of Thermophysics. S.S. Kutateladze SB RAS Institute of Theoretical and Applied Mechanics. S.A. Khristianovich SB RAS The main scientific topics of the journal are: - fluid dynamics - heat and mass transfer - turbulence - means and methods of aerial and thermophysical experiments - physics of low-temperature plasma - physical and technical problems of power engineering

However, with an increase in flight speeds above M \u003d 4, the dimensions of the Mach disk significantly decrease and the frontal<...> At moderate supersonic freestream Mach numbers, the Mach disk has a certain finite transverse<...> The size of the Mach disk decreases significantly with an increase in the freestream Mach number.<...>Mach, and then subsequent systems of funnel-shaped shock waves with Mach disks are formed.<...> must correspond to the presence of Mach discs (with a subsonic flow rate immediately behind them).

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A numerical simulation of the flow formed during transverse injection of a jet into a supersonic flow through a slot nozzle is carried out at various pressures in the injected jet and in the main flow. For calculations on grids with different resolution, the Spalart – Almaras turbulence model, the k – ε model, the k – ω model, and the SST model are used. Based on a comparison of the calculated and experimental data on the pressure distribution on the wall, the length of the recirculation region, and the depth of the jet penetration into the supersonic flow, conclusions are drawn about the accuracy of the results of calculations using various turbulence models and the applicability of these models to solving similar problems.

Mach and shock wave due to re-compression of the flow.<...> <...> injection, and the depth of penetration of the jet into the main stream H, which is determined by the position of the upper edge of the disk<...>Mach.<...>Mach 5.

A computational and theoretical study of the features of the flow of supersonic high-enthalpy flows in narrow cylindrical channels is carried out. The mathematical model is based on the solution of the complete non-stationary system of Navier - Stokes equations in an axisymmetric setting. The calculations are performed for laminar and turbulent flow regimes using various turbulence models. The influence of the geometric parameters of the channel on the flow characteristics is analyzed. The features of the distribution of the Mach number along the radius of the flow in different sections of the channel are considered. It is shown that, depending on the conditions, deceleration of different intensity takes place up to the formation of a subsonic flow zone of considerable length in the channel.

has several maxima, which, in our opinion, corresponds to the formation of additional jumps behind the disk<...>Mach when decelerating a supersonic flow).<...> supersonic flows in narrow cylindrical channels 15 such as the mentioned additional jumps behind the disk<...>Mach can be identified more clearly.<...> supersonic flows in narrow cylindrical channels 17 in the k - ε model, the first disk is displaced

The paper simulates a supersonic air flow in a flat channel with transverse injection of a turbulent hydrogen jet through a slit on the bottom wall. An algorithm for solving the Favre-averaged Navier – Stokes equations for the flow of a perfect multicomponent gas based on the WENO scheme is proposed. The main attention is paid to the interaction of the shock-wave structure with boundary layers on the lower and upper walls of the channel under conditions of internal turbulent flow, namely, a detailed study of the flow structures was carried out, separation and mixing were investigated depending on the width of the jet slot. It was found that, in addition to the well-known shock-wave structures that arise during the interaction of the incident flow with the transverse jet and during the interaction of the bow shock with the boundary layers near the walls, an additional system of shock waves and flow separation on the lower wall at some distance from the jet downstream are formed. Comparison with experimental data is carried out.

On the graphs of isobars 4, the Mach disk is clearly visible.<...> the size of the slot leads to the expansion of the barrel-shaped structure in the jet and, as a consequence, to an increase in the disk<...>Mach (Fig. 4a and 4b).<...> However, in the case of the maximum slit size (h3) (Fig.4c), the Mach disk decreases, since the separation zone<...>Mach, which is demonstrated by the distribution of the local Mach number (2 2M, u w c \u003d + here c the local speed

<...> <...> <...>

A three-dimensional supersonic turbulent flow with symmetric perpendicular injection of circular jets from the channel walls is numerically simulated. Using an algorithm based on the ENO-scheme, the original Favre-averaged Navier – Stokes equations, closed using the (k – ω) turbulence model, are solved. For the values \u200b\u200bof the off-design parameter 3 6 n 6 50, the mechanism of the formation of vortex structures during the interaction of the jet with the incident flow is studied. It has been experimentally established that for n\u003e 10, as a result of mixing of the jet and the incoming high-speed flow, a pair of vortices appears and additional separation occurs near the wall behind the jet. It is shown that the results of calculating the pressure distribution on the wall ahead of the jet in the plane of symmetry are in satisfactory agreement with the experimental data.

flows behind the jet due to the formation of a low pressure zone; barrel and disc formation<...>Mach in the stream.<...> are formed in the mixing zone, a pair of vortices 9 is formed due to the interaction of the jet passing through the disk<...>Mach D, high-speed freewheel.<...> way: - in the jet u \u003d 0, v \u003d 0, T \u003d 0.6, w \u003d √ T M0 / M∞, P0 \u003d nP∞, z \u003d 0, x 2 + y2 6 R (M0 is the Mach number

The results of spectroscopy of the initial section of a supersonic plasma jet formed by a pulsed discharge in a capillary with an ablating wall made of a carbon-containing polymer are presented. The features of the spatial distribution of the electron density and the intensity of the spectral components, which, in particular, are caused by the high value of the electron temperature in the "hot" central zone, exceeding the "normal" temperature, as well as the significant nonisobaricity of the initial section of the supersonic jet, are revealed. The radiative properties of the high-temperature jet core (intensity and contour of the Balmer lines Hα and Hβ, relative intensities of C II ion lines) recorded with a high temporal (1-50 μs) and spatial (30-50 μm) resolution made it possible to establish the main regularities in the pressure and temperature distributions in the vicinity of the central shock. Due to the presence of molecular components in the flow, which exhibit their radiative properties at the periphery of the jet, it was possible to get an idea of \u200b\u200bthe plasma parameters in the zone of formation of "hanging" shock waves.

based on the results of optical visualization of the flow and by analyzing shock-wave structures: Mach number<...> The temperatures determined in this way are Te ~ 2 eV in the vicinity of the Mach disk (z \u003d 2.5<...> The pressure profile p (r) reconstructed using the above procedure in the vicinity of the Mach disk is qualitatively<...> The reconstructed pressure profile in the vicinity of the Mach disk is in qualitative and quantitative agreement with the results

No. 3 [Thermal physics and aeromechanics, 2018]

At moderate supersonic freestream Mach numbers, the Mach disk has a finite transverse dimension<...> The dimensions of the Mach disk significantly decrease with an increase in the freestream Mach number, and in the obtained<...> must correspond to the presence of Mach disks with a subsonic flow rate immediately behind them.<...>Mach pseudoshock.<...> behind the second Mach disk (x \u003d 3.93 m, x \u003d 10.15), curve 5 ⎯ end of the separation zone of the boundary layer (x \u003d

Preview: Thermophysics and Aeromechanics No.3 2018.pdf (0.5 Mb)

The results of experimental studies and numerical simulation of self-oscillations in a supersonic radial jet flowing from a flat radial nozzle into a flooded space are presented. It is shown that flexural vibrations develop in the jet, leading to its destruction. It has been established that a large role in the formation of self-oscillations is played by feedback, which is carried out by sound waves in the gas surrounding the supersonic jet.

bounded by cylindrical surfaces with radii r1, r2, and a radial channel bounded by two disks<...> The angle of inclination of Mach waves relative to the jet axis is α ≈ 40 °.<...> In fig. 6 shows the distribution of the Mach number on the jet axis at various times.<...> Using these values, we find the convective Mach number of the jet Mc \u003d 2M / (1+ c0 / cj) ≈ 2.3.<...> a given outflow regime on the jet axis, there is a regular interaction of shock waves without the formation of a disk

Experimental study of the influence of acoustic-vortex self-oscillations on the process of destruction of an underexpanded supersonic jet in a flooded space [Electronic resource] / Aleksandrov, Arefiev, Ilchenko // Thermal physics and aeromechanics .- 2016 .- No. 4 .- P. 45-55 .- Access mode: https: // site / efd / 434738

The intensification of mixing of the gaseous working medium supplied through the jet nozzles with the environment is an important scientific and technical problem, the solution of which will increase the efficiency of the working process in power and power plants. A relevant, but little-studied direction is the generation of acoustic-vortex self-oscillations in jet nozzles, which can accelerate the decay of a supersonic jet and thereby improve the mixing performance. The article presents the features of excitation of acoustic-vortex self-oscillations in jet nozzles; the main results of an experimental study of a model jet nozzle, in the channel of which plates are installed, providing excitation of acoustic-vortex self-oscillations are presented; the regularities of the decay of an underexpanded supersonic jet in a submerged space are found for different flow regimes. The presented data show the possibility of effective application of jet nozzles with generated acoustic-vortex self-oscillations as applied to gaseous fuel supply systems. The results of the study can be used in the design of power plants for advanced samples of aerospace technology and technological devices.

Reflection from the jet axis of the shock wave leads to the formation of a Mach 7 disk.<...> The frequency of the acting force is determined by the formula: St M, f c t \u003d ⋅ ⋅ here M is the Mach number of the flow in the cavity<...> centered vacuum wave, 4  jet boundary, 5  compression wave, 6 hanging shock, 7 7 disk<...>Mach, 8  reflected shock, 9  external mixing region.<...> In the experiments, the change in the Mach number in the cavity was controlled by changing the diameter d of the MF nozzle.

No. 3 [Applied Mechanics and Technical Physics, 2004]

shock waves 3, 4, 5; 7 - fan of rarefaction waves; b: 1 - nozzle; 2 - jump in compression; 3 - Mach disk<...>Mach near the axis (r / Ra \u003d 0 ÷ 0.15).<...> Free stream Mach number M \u003d 5.<...>Mach.<...> time may result in the loss of information recorded on the disc.

Preview: Applied Mechanics and Technical Physics No. 3 2004.pdf (0.3 Mb)

No. 5 [Physics of combustion and explosion, 2015]

The journal publishes articles with the results of original experimental and theoretical studies in the following sections: combustion in gases and condensed media, detonation of condensed explosives, gases and heterogeneous systems, production of new materials by the method of self-propagating high-temperature synthesis, shock and detonation waves, high-speed shock, dynamic loading of materials and structures, welding explosion and detonation spraying

Mach 3, and the flow velocity immediately behind the Mach disk becomes subsonic.<...> The flow velocity in front of the Mach disk reaches V \u003d 545 m / s according to PIV Fig. five.<...> Further behind the Mach disk, the velocity drops abruptly to V \u003d 190 m / s and U \u003d 95 m / s (PIV and calculation, respectively<...> Even on a direct jump (Mach disk), due to averaging over a large number of instantaneous realizations, one can see<...> In fig. 6 also shows that behind the Mach disk, after a sharp deceleration of the flow, the velocity lag of particles

Preview: Physics of Combustion and Explosion No. 5 2015.pdf (0.1 Mb)

M .: Publishing house of MSTU im. N.E. Bauman

The principles of magnetic-inertial thermonuclear fusion and laser-plasma methods of generating fields during the implosion of a magnetized target are considered. The results of the work open up the possibility of creating new high-density plasma sources for their use in materials science experiments and for promising areas of power engineering. Such plasma systems can be used for diagnostics and testing of various materials. The Richtmyer - Meshkov instability in impulsive systems with inertial confinement of particles is investigated.

field, that is, at 0) B \u003d, consisting of a group of lateral hanging shock waves (SW) and a central disk<...>Mach crossing the axis of symmetry.<...> Here, behind the central Mach disk (at subsequent instants of time), a vortex wake (toroidal<...> In this case, it is limited in the radial coordinate by the size of 1 cm. R ≤ In this spatial zone, the Mach number<...> structure, and the maximum temperature in the jet is at the level of 3max 18 10 K, T ≈ ⋅ Mach number

No. 3 [Thermophysics and Aeromechanics, 2017]

The diameter of this disk depends on the freestream Mach number and the incident shock intensity.<...> In the case under consideration, the Mach disk practically does not manifest itself as when falling on the axis of the initial shock<...> This is due to the high flow rate when the initial Mach disk of small transverse size is formed<...>Mach of a larger size, then subsequent Mach disks are formed (Fig. 4b).<...> The region with separations and Mach disks gradually moves forward, and as a result, before the

Preview: Thermophysics and Aeromechanics No. 3 2017.pdf (0.5 Mb)

No. 5 [Applied Mechanics and Technical Physics, 2015]

The journal publishes original articles and custom reviews on the mechanics of liquid, gas, plasma, dynamics of multiphase media, physics and mechanics of explosive processes, electric discharge, shock waves, state and motion of matter at ultrahigh parameters, thermal physics, mechanics of a deformable solid, composite materials, methods diagnostics of gas-dynamic physical and chemical processes.

Mach in the stream.<...> The area of \u200b\u200bpenetration of the jet into the main flow is limited by hanging shock waves and a Mach disk.<...>Mach.<...>Mach 5.<...> An experimental study of the lifting of a circular glass disk from the surface of the water, the purpose of which was

Preview: Applied Mechanics and Technical Physics No. 5 2015.pdf (0.2 Mb)

Parallel calculations in solving problems of aerohydrodynamics by the method of large particles textbook. tutorial on the course "Parallel programming"

M .: Publishing house of MSTU im. N.E. Bauman

Problems of flow around bodies of different geometric shapes at different speeds of the incident flow (subsonic and supersonic) are considered in plane and axisymmetric cases in the entire range of permeability: from impermeability to free flow. The descriptions of programs for the calculation of three-dimensional nonstationary problems taking into account the gravitational field (problems of the Rayleigh - Taylor instability) using the difference scheme of the method of large particles on triangular, hexagonal and orthogonal computational grids are given. The textbook is accompanied by a CD containing the texts of 20 working programs in the algorithmic FORTRAN language, intended for solving the problems of aerohydrodynamics using the KRUCHA-2 PPP.

Flow patterns: a - a thin permeable body; b - disc with a visor-shell 2.<...> and P (30, 2) \u003d 0.63 behind the disk near the axis of symmetry at the time TK \u003d 20.00.<...> and P (30, 2) \u003d 0.78 behind the disk near the axis of symmetry at the time TK \u003d 20.00.<...> and P (30, 2) \u003d 0.80 behind the disk near the axis of symmetry at the time TK \u003d 20.00.<...> and RO (30, 2) \u003d 0.47 behind the disk near the axis of symmetry at time TK \u003d 20.00.

Preview: Parallel calculations of aerohydrodynamics problem by the method of large particles.pdf (0.1 Mb)

Teaching balances and turns in sports aerobics textbook. allowance

Publishing house of Siberian State University of Physical Culture

The textbook provides information on the technique of performing balances and turns, as well as the methodology for teaching these elements, taking into account the physical qualities and functional abilities necessary for successful training at the stage of initial training in sports types of gymnastics. The manual provides new information, reflecting the methodology of teaching balances and turns in sports aerobics, based on the general biomechanical patterns of their implementation, taking into account the requirements of the competition rules of this popular kind of sport among young people.

Balance with a tilt (vertical swing). 2. Exploring the 180 ° rotation on the "health disc". 3.<...> on the "health disc", arms to the sides: 1–2 - push with the left and swing the arms to rotate on the disc by 360; 3-4 -<...> health ", left on the floor, arms to the sides: 1–2 - by pushing the left and swinging the arms, turn on the disc by 360,<...> , left on the floor, arms to the sides: 1–2 - by pushing the left and swinging the arms, turn on the disc by 360, bending the left<...> to the floor, arms to the sides: 1–2 - by pushing the left and swinging the arms, turn on the disc by 360 with closed eyes;

Preview: Teaching balances and turns in sports aerobics. 2013 ed..pdf (0.3 Mb)

No. 5 [Applied Mechanics and Technical Physics, 2001]

In this case, the inner diameter of the jet, determined from the diameter of the Mach disk, is almost 10 times<...>Mach, the flow around the element occurs without the departure of the Mach disk.<...> Under these conditions, there is no significant change in the jet size behind the Mach disk, and the area<...> jets around the side holes can be taken as the area of \u200b\u200bthe jet at the level of the Mach disk.<...> For practical use with a Mach disk diameter 10 times the outlet diameter

Preview: Applied Mechanics and Technical Physics No. 5 2001.pdf (0.3 Mb)

No. 2 [Applied Mechanics and Technical Physics, 2010]

As well as a set of discs and a fairing.<...> Upper profiled disc, disc set, upper rotor fairing and guide top edge<...> ; N is the number of revolutions per minute of the classifier disks.<...>Mach, jet boundary.<...> Calculated distribution of Mach numbers at the exit of a multimode nozzle with different Mach numbers at the exit

Preview: Applied Mechanics and Technical Physics No. 2 2010.pdf (0.2 Mb)

Thermogasdynamic calculation of centrifugal compressors textbook. allowance

The method of calculation is stated and the algorithm for calculating the flow path of a centrifugal stationary compressor is presented. Examples of calculations of impellers, diffusers, back-guiding apparatus, outlet device are given. The issues of optimization and selection of the compressor flow path are considered.

in section i; 111 awM w \u003d - Mach number in section 1 at speed 1w; 222 acM c \u003d - Mach number in the section<...> Mach number at peripheral speed (conventional Mach number) .612.0 28558.49695.030.1 83.25522 \u003d ⋅⋅⋅ \u003d\u003d\u003d nn<...> A closed wheel consists of a main disk 1, a cover disk 2 and blades 3 (Fig. 7.1).<...> The vanes can be solid milled together with the main disc, and the cover disc is soldered to them.<...> The blades are first welded to the main disc and then the cover disc is soldered to the blades.

Preview: Thermogasdynamic calculation of centrifugal compressors. Tutorial.pdf (0.2 Mb)

Run! Jump! Throw! The IAAF Official Guidelines for Teaching Athletics: [study guide. manual]

M .: Man

The IAAF Official Athletics Training Guide “Run! Jump! Throw! " divided into three main sections, each of which covers one group of species, which is the title of the section. The main sections begin with a very brief overview and background of each group of species. This includes the most important sections of the core theory - general goals, basic biomechanical principles and an overview of structural phases - basic exercises, teaching guidelines and examples of games to help introduce the skills required to practice the species in this group. The Running Views section also provides a quick overview of your middle and long distance running workout.

the leg swings in front of the torso and straightens for contact (forward swing), while the jog<...> Copyright OJSC "CDB" BIBCOM "& LLC" Agency Book-Service "182 DISC THROWING DISC THROWING<...>swing backward and ▲ active - forward.<...> NOTES: Do not grab the disc. ▲ Bend your legs as you roll the ▲ disc on the ground.<...> REMARKS: Hold the disc at the level of ▲ of the head. Feel the disc release through the ▲ index finger.

Preview: Run! Jump! Throw! The Official IAAF Training Guide to Athletics.pdf (0.3 MB)

Methodology of strength development in the process of physical education of students at a university method. recommendation

This work introduces students to the methods of developing strength abilities in physical education classes. The paper discusses the basic and additional tools that can be used in physical education classes for the development of strength abilities of students. In this work, control exercises are proposed to determine the level of development of strength abilities.

Bend forward to perform with a floor squat and swing your arms back, straightening with a swing of your arms forward and up<...> Breathing: swing your legs back, inhale, exhale forward. 7.<...> Breathing: swing legs up, inhale, legs down, exhale. 8.<...> Breathing: in and. n. inhale, swing exhale. 37.<...> one leg, simultaneously swinging the hip of one leg.

Preview: Methodology for the development of strength in the process of physical education of students at the university.pdf (0,5 Mb)

No. 3 [Thermal physics and aeromechanics, 2019]

Estimates from the data showed that for a water drop with d \u003d 2.7 mm, the Mach numbers of the shock wave are Ms \u003d 1.3, 1.5<...>Mach 5 at NPR \u003d 4 (Fig.4a) and NPR \u003d 6 (Fig.4c).<...>Mach " in a pure gas, and in the two-phase core of the jet it is an indirect sign of the existence of a" third<...>Mach in a supersonic underexpanded jet consisting only of gas.<...> Here M∞ is the Mach number, Re1 is the unit Reynolds number, T∞ is the incident flow temperature, p∞ is the pressure

Preview: Thermophysics and Aeromechanics No. 3 2019.pdf (0.5 Mb)

Athletics. Question-answer methodical recommendations for students of the Faculty of Physical Education of higher educational institutions

FSBEI HPE "ShSPU"

Methodical recommendations are made on the basis of the educational-methodical complex for the discipline "Athletics", developed at the department of sports disciplines of GOU VPO "ShSPU". Recommendations are intended for students of the Faculty of Physical Education of pedagogical universities, teachers and physical education teachers.

Holding the disc.<...> Turns without disc and with disc at different speeds. 2.<...>Swing your leg while standing against the wall on a push leg. 2.<...> Trainers find it more effective to swing the straightened leg.<...>Disk.

Preview: Athletics. FAQ.pdf (0.5 Mb)

No. 6 [Applied Mechanics and Technical Physics, 2009]

In the works, overexpanded jets are considered, and the Mach disk and subsonic zone are obtained by calculation.<...> In the case of an underexpanded jet, a flow field with a vortex formed behind the Mach disk was obtained.<...> Since the flow in the nozzle was off-design, oblique shocks and a Mach disk were formed inside it, and<...> In front of the Mach disk, the gas is accelerated to the Mach number on the axis M \u003d 6.8; 4.4 corresponding to the values<...> On the calculation of a supersonic overexpanded jet of ideal gas in the presence of a Mach disk in the flow.

Preview: Applied Mechanics and Technical Physics No. 6 2009.pdf (0.2 Mb)

Athletics: the basics of knowledge (in questions and answers) textbook. allowance

The manual contains brief information on the history of the development of types of athletics, the analysis of techniques and methods of teaching athletics exercises, the organization and the basic rules of judging competitions in the sport, which are set out in a form convenient for learning and mastering. Typical mistakes when performing athletics exercises and recommendations for their correction are given.

copper or bronze disc.<...> In the long jump, the swing is performed with one hand up and down, in the triple jump, the swing is performed as with two<...> , the disk is around the vertical.<...> Swing with a bent leg. The radius of the circle is 8–10 m. 2.<...>swing heel forward) 2.

Preview: Athletics Fundamentals of Knowledge (Q&A) .pdf (0.6 MB)

Initial motor training in sports aerobics textbook. allowance

Publishing house of Siberian State University of Physical Culture

The manual is written on the basis of the requirements of the federal state educational standard of higher professional education, direction 034300.62 "Physical culture", and the work program of the discipline "Theory and methodology of the chosen type of physical culture and sports activity." The textbook substantiates the structure of the types of initial training in sports aerobics, presents complexes of special exercises in combination with training devices for initial physical training in sports aerobics, sets out the main organizational forms of educational and extracurricular work.

right back within 40 °; 2 swing right forward upward; 3 - swing right back; 4 swing right forward up<...> health, 1_2 _ jerk (, m left and swing the HANDS, turn on the disc on the ZM ’°’ left back to the BOTTOM; 3-4 then S<...> “’ M with the left and with a wave of the hands, turn on the disk to ZbO ° C0GNUV left forward; 3 -4 the same; 5-8 same 1, but left AND<...> RUSHVST ° R ° Hb1: 1 -2 push with the left ° d and swing of the hands, turn on the disc by 36 "with closed eyes; 3-4 the same<...> * in the th stance on the right, on the health disc; 6 jerk - "with the eva and swing of the HAND turn to the right by 360 7

Preview: Initial motor training in sports aerobics.-2nd ed., Revised. and add. 2013 ed..pdf (1.2 Mb)

Special exercises for teaching types of athletics textbook. allowance

Sib. Feder. un-t

Contains a systematic presentation of methodological and practical material on athletics, which is necessary for students of higher educational institutions to master the profession of a trainer-teacher, a teacher of physical culture. Cinegrams and schemes of technique in the main types of athletics - running and walking, jumping and throwing - with methodological recommendations for their development, as well as examples of the main lead-in, imitation and special training exercises for training sections are presented.

Swing your leg while standing sideways against the gymnastic wall.<...> Swing without moving the body forward and up; simultaneously with the swing, the body deviates back<...> Jumps on one leg back forward: a) without swinging the left leg, b) with swinging the left leg, c) with staging<...> Simulation exercises for teaching the technique of discus throwing Disc and hammer throws are assigned to students<...> The mass of the male disk is 2 kg, the female disk is 1 kg.

Preview: Special exercises for teaching types of athletics.pdf (0,4 Mb)

Calculation of crank presses textbook. allowance

This manual describes the procedure for performing calculations related to the design of the drive, parts and assemblies of crank presses. The schemes and calculated dependencies necessary for this are presented. Complete reference material is given. Intended for university students in the study of disciplines: "Forging and stamping equipment", "Calculation and design of forging and stamping equipment."

Data for determination of friction parameters and disc thicknesses 60 5.2.3.<...> Calculate the estimated length of the belts by the formula:     2 0.25 2 1.57 max shk max shk D D L D D     <...>    2 2 0.25 1.57 0.125max shk max shk L D D D D     .<...> , cm hд Thickness of the driving disk, cm h1 Number of inserts, pcs mw 5.2.3.<...> Drive disc thickness 1 (0.11 0.0002) mh B n   . (5.17) 5.3.4.

Preview: Calculation of crank presses.pdf (0.7 Mb)

Rhythmic gymnastics at the university

Voronezh State University Publishing and Printing Center

The teaching aid was prepared at the Department of Physical Education and Sports of Voronezh State University.

I. p. - emphasis on the knees: 1 - swing the right leg back; 2 - sitting on the heels; 3 - swing the left leg back<...> I. p. - emphasis on the knees: 1 - swing the right leg back; 2 - swing with the right leg to the right; 3 - account 1; 4<...> .; 3 - swing the leg forward; 4 - and. P.; 5 - leg back; 6 - and. P.; 7 - swing up; 8 - and. p. 36.<...> I. p. - the same: 1 - swing right forward; 2 - swing from the right to the left hand; 3 - swing right forward; 4 - and. P.<...> Walking in a disco manner. Walking slowly. 26.

Preview: Rhythmic gymnastics in the university.pdf (0.5 Mb)

No. 5 [Thermal physics and aeromechanics, 2016]

Mach number 10, height 90 km.<...>Mach.<...>Mach a strong jet bounded by the contact surface.<...> As the speed of rotation of the disk on the cylinder axis increases, the axial component decelerates first<...> With a further increase in the disk rotation, this region with a reduced value of the axial velocity component

Preview: Thermophysics and Aeromechanics No. 6 2014.pdf (1,1 Mb)

No. 6 [Applied Mechanics and Technical Physics, 2017]

Calculation and design of centrifugal compressor machines textbook. allowance

Publishing house of OmSTU

In the 2nd edition of the textbook, the issues of thermogasdynamic calculation, design and strength analysis of elements of the flow path of centrifugal compressors are considered; describes the thermogasdynamic design of the flow path using the calculation method through dimensionless parameters; examples of thermogasdynamic and strength calculations are given.

Mach number MW1 should have values \u200b\u200bMW1  0.55 ... 0.65 (for axial radial RK MW1  0.87).<...> To determine the Mach number in the "throat" section of the RK MW1G, you can use the technique developed<...> The Mach number for speed at the outlet of the diffuser is 444 TRkСMС . (1.119) Gas pressure, Pa:  .) 1 () 1 (<...> To the calculation of Mach numbers in the "throat" section of the grating of a blade diffuser Equation (1.130) is nonlinear,<...> In this case, the conditional Mach numbers for the RK section I are obtained sufficiently large MU \u003d 0.88, and the Mach numbers by

Preview: Calculation and design of centrifugal compressor machines A. D. Vanyashov, G. G. Kustikov, 2017. - 255 pp. Pdf (0.9 Mb)

No. 3 [Applied Mechanics and Technical Physics, 2011]

An important gas-dynamic characteristic of a supersonic jet is the position of the Mach disk - a straight shock<...> The position of the Mach disk was determined by the formula lM \u003d 0.67d * √ p0 / pк, where lM is the distance to the Mach disk<...> These data made it possible to estimate the flow regimes in the jets and to determine the position of the Mach disk at different<...> For measurements in the supersonic region of the jet (in front of the Mach disk), a point was chosen at a distance from the cut<...> nozzle equal to 8 mm, in the area behind the Mach disk - a point at a distance from the nozzle exit equal to 50 mm.

Preview: Applied Mechanics and Technical Physics No. 3 2011.pdf (0.2 Mb)

No. 1 [Bulletin of the Moscow State Technical University named after N.E. Bauman. Series "Mechanical Engineering", 2010]

M .: Publishing house of MSTU im. N.E. Bauman

Issues in the following areas are covered: mechanics of load-bearing structures for various purposes; energy problems; modern technology problems; fundamental problems of mathematics, physics, continuum mechanics, etc.

At Mach numbers M\u003e 3, it is necessary to switch to a direct-flow circuit.<...> Mach number fields in the central axial section during flight with zero angle of attack for Mach numbers M \u003d 6,8,10<...> The dependences of these characteristics on the Mach number and angle of attack were investigated.<...> ; μ - coefficient of friction between the block and disk 45

No. 3 [News of the Russian Academy of Sciences. Mechanics of liquid and gas, 2017]

Theoretical, computational and applied research in the field of aeromechanics, hydrodynamics, plasma dynamics, soil hydrodynamics, biomechanics of continuous media are published. Special attention is paid to new areas of research, such as the theory of multiphase flows and their application, chemically reactive flows, flows of liquids and gases in electromagnetic fields, new hydrodynamic methods for increasing oil production, new approaches to the description of turbulent flows, etc. The journal is peer-reviewed and included in the List of VAK.

front view, the angle between the line of sight and the axis of the disc Θ \u003d 0 °; b - from the side Θ \u003d 90 °; c - the disk is turned at an angle<...> Plane and axisymmetric configurations streamlined with the maximum critical Mach number // Prikl. 1987<...> Optimization of the shape of symmetric flat bodies in order to increase the critical Mach number // Uch. app.<...> Mach number M1 of the total velocity of a uniform flow behind a plane shock wave attached to the forward<...> the edge of the leeward console, or behind a centered rarefaction wave (symbols I); Mns - Mach number

Preview: Bulletin of the Russian Academy of Sciences. Mechanics of Liquid and Gas No. 3 2017.pdf (0.1 Mb)

The National Training Methodological Center for Testing Abrasive Materials at the request of the editorial board of the magazine "KUZOV" has started a new series of tests. The center's research includes testing abrasives in P120 grit circles, one of the most common grades used in bodywork, on two types of surfaces - putty and metal with putty. The test involves abrasive wheels of fourteen series of different manufacturers - almost everyone who is present on the Russian market today, from leaders to little-known brands. All samples are tested under exactly the same conditions, on an identical surface, at the same humidity and temperature. According to the results of two tests, the tested abrasive wheels were awarded points according to the system 1 point for the minimum result and further in ascending order

During the test, the disc wear was uneven.<...> The NORTON A275 disk also worked stably.<...> OJSC Central Design Bureau BIBCOM & LLC Agency Book-Service BODY 201363 C L E S A R N Y c E x 1 accrual<...> RADEX Gold 9 4 12 Skilled Red 10 3 12 NORTON A275 10 3 11 Siarun 11 2 8 Mirka Abranet 12 1 1 accrual of max<...> Skilled Red 13 5 81 siarun 14 4 75 NORTON A275 15 3 53 Mirka Abranet 16 2 46 RADEX Gold 17 1 2

No. 4 [Thermal physics and aeromechanics, 2014]

I installed VirtualBox on my Linux PC. I really wanted to use one of the LXFDVDs to install a virtual Linux system. But I am getting an error that states that VirtualBox does not recognize the disk format. I think the reason is because the disc is a hybrid ISO file. Can I create a standard ISO disk image for Linux installation in Virtual Box? If so, how do you do it?

I think the reason is that the disc is an ISO hybrid file.<...> This will enable you to select the physical disk you are using.<...> A large, secure remote, such as Tails, unless loaded in newer systems<...> This is not a requirement of Windows 10, which also boots in older BIOS / MBR systems, but<...> and for writing tags, the quality of the copied files will be the same in all programs

Type

Search results for \\ "disk drive \\". Fundamental research Teaching balances and turns in sports aerobics textbook. allowance

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Health-improving and professional-applied efficiency of mass physical culture work in a vocational school dormitory (for example, a building one)

No. 5 [Thermal physics and aeromechanics, 2015]

No. 1 [Thermal physics and aeromechanics, 2018]

No. 3 [Thermal physics and aeromechanics, 2018]

No. 3 [Applied Mechanics and Technical Physics, 2004]

No. 5 [Physics of combustion and explosion, 2015]

No. 3 [Thermophysics and Aeromechanics, 2017]

No. 5 [Applied Mechanics and Technical Physics, 2015]

Parallel calculations in solving problems of aerohydrodynamics by the method of large particles textbook. tutorial on the course "Parallel programming"

Teaching balances and turns in sports aerobics textbook. allowance

No. 5 [Applied Mechanics and Technical Physics, 2001]

No. 2 [Applied Mechanics and Technical Physics, 2010]

Thermogasdynamic calculation of centrifugal compressors textbook. allowance

Run! Jump! Throw! The IAAF Official Guidelines for Teaching Athletics: [study guide. manual]

Methodology of strength development in the process of physical education of students at a university method. recommendation

No. 3 [Thermal physics and aeromechanics, 2019]

Athletics. Question-answer methodical recommendations for students of the Faculty of Physical Education of higher educational institutions

No. 6 [Applied Mechanics and Technical Physics, 2009]

Athletics: the basics of knowledge (in questions and answers) textbook. allowance

Initial motor training in sports aerobics textbook. allowance

Special exercises for teaching types of athletics textbook. allowance

Calculation of crank presses textbook. allowance

Rhythmic gymnastics at the university

No. 5 [Thermal physics and aeromechanics, 2016]

No. 6 [Applied Mechanics and Technical Physics, 2017]

Calculation and design of centrifugal compressor machines textbook. allowance

No. 3 [Applied Mechanics and Technical Physics, 2011]

No. 1 [Bulletin of the Moscow State Technical University named after N.E. Bauman. Series "Mechanical Engineering", 2010]

No. 3 [News of the Russian Academy of Sciences. Mechanics of liquid and gas, 2017]

No. 4 [Thermal physics and aeromechanics, 2014]

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