scholarly journals Малогазовая детонация в низкоплотных механоактивированных порошковых смесях

2019 ◽  
Vol 89 (6) ◽  
pp. 821
Author(s):  
С.А. Рашковский ◽  
А.Ю. Долгобородов
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Energy Release ◽  
Powder Mixture ◽  
Powder Compaction ◽  
Mutual Friction ◽  
Low Density ◽  
Powder Mixtures ◽  
Release Wave ◽  
Fuel Particles

Experimental data on supersonic self-sustaining propagation of the energy release wave in low-density mechanically activated powder mixtures are analyzed. Various mechanisms that may be responsible for this process are analyzed, and a mechanism for the detonation-like propagation of the reaction in powder mixtures is proposed. It is shown that under certain conditions this process has all the signs of detonation and should be recognized as one of the types of detonation. It is shown that this type of detonation is fundamentally different from the classical "ideal" detonation, for example, in gases: instead of a shock wave, a compaction wave propagates through the powder mixture, in which there is basically no compression of the particle material, but powder compaction occurs due to the mutual rearrangement of particles. In this case, the initiation of a chemical reaction occurs due to the mutual friction of the oxidizer and fuel particles in the powder compaction wave.

Calculation of the Shock Adiabat of Powder Mixtures With a Glance a Dependence of the Grüneisen Coefficient on Temperature

2009 ◽  
Vol 4 (4) ◽  
pp. 71-78
Author(s):  
Sergey Kinelovskiy ◽  
Konstantin Maevskiy
Keyword(s):  
Experimental Data ◽  
Explicit Form ◽  
Powder Mixture ◽  
Shock Adiabat ◽  
Condensed Phases ◽  
Powder Mixtures ◽  
Model Dependence ◽  
Grüneisen Coefficient ◽  
Gruneisen Coefficient

In work the model, allowing to calculate a shock adiabat of a powder mixture is offered. In model dependence of Grüneisen coefficient in an explicit form only from temperature is considered. Comparison of effects of calculations with known experimental effects of different authors for powders and intermixtures of various compositions is made. It is shown that calculation yields the good consent with experiment for two- and ternary (on number of condensed phases) intermixtures for all experimental data known to authors.

Shock-wave compacting of a Fe-Ni-Al powder mixture and its study

2006 ◽  
Vol 102 (5) ◽  
pp. 541-544
Author(s):  
F. Kh. Akopov ◽  
V. M. Gabuniya ◽  
G. I. Mamniashvili ◽  
G. S. Martkoplishvili ◽  
G. Sh. Oniashvili ◽  
...  
Keyword(s):  
Shock Wave ◽  
Powder Mixture ◽  
Al Powder

An Investigation on the Mechanical Alloying of TiFe Compound by High-Energy Ball Milling

2010 ◽  
Vol 660-661 ◽  
pp. 329-334 ◽  
Author(s):  
Railson Bolsoni Falcão ◽  
Edgar Djalma Campos Carneiro Dammann ◽  
Cláudio José da Rocha ◽  
Ricardo Mendes Leal Neto
Keyword(s):  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Powder Mixtures ◽  
Milling Parameters ◽  
Process Route ◽  
Partial Formation ◽  
Energy Ball

This work reports the efforts to obtain TiFe intermetallic compound by high-energy ball milling of Ti and Fe powder mixtures. This process route has been used to provide a better hydrogen intake in this compound. Milling was carried out in a SPEX mill at different times. Strong adherence of material at the vial walls was seen to be the main problem at milling times higher than 1 hour. Attempts to solve this problem were accomplished by adding different process control agents, like ethanol, stearic acid, low density polyethylene, benzene and cyclohexane at variable quantities and keeping constant other milling parameters like ball to powder ration and balls size. Better results were attained with benzene and cyclohexane, but with partial formation of TiFe compound even after a heat treatment (annealing) of the milled samples.

scholarly journals Approximate Analytical Models of Shock-Wave Structure at Steady Mach Reflection

Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 305
Author(s):  
Mikhail V. Chernyshov ◽  
Karina E. Savelova ◽  
Anna S. Kapralova
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Comparative Analysis ◽  
Analytical Model ◽  
Mach Reflection ◽  
Supersonic Jet ◽  
Wave Structure ◽  
Analytical Models ◽  
Analytical Prediction ◽  
Shock Wave Structure

In this study, we obtain the comparative analysis of methods of quick approximate analytical prediction of Mach shock height in planar steady supersonic flows (for example, in supersonic jet flow and in narrowing channel between two wedges), that are developed since the 1980s and being actively modernized now. A new analytical model based on flow averaging downstream curved Mach shock is proposed, which seems more accurate than preceding models, comparing with numerical and experimental data.

A 3-D Thin Layer Navier-Stokes Code for Supersonic Laminar and Turbulent Flows

2002 ◽  
Author(s):  
Omid Abouali ◽  
Mohammad M. Alishahi ◽  
Homayoon Emdad ◽  
Goodarz Ahmadi
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Mach Number ◽  
Turbulent Flows ◽  
Turbulence Modeling ◽  
Cross Flow ◽  
Navier Stokes ◽  
Cross Sectional ◽  
Laminar And Turbulent Flows ◽  
Circumferential Pressure

A 3-D Thin Layer Navier-Stokes (TLNS) code for solving viscous supersonic flows is developed. The new code uses several numerical algorithms for space and time discretization together with appropriate turbulence modeling. Roe’s method is used for discretizing the convective terms and the central differencing scheme is employed for the viscous terms. An explicit time marching technique and a finite volume space discretization are used. The developed computational model can handle both laminar and turbulent flows. The Baldwin-Lomax model and Degani-Schiff modifications are used for turbulence modeling. The computational model is applied to a hypersonic laminar flow at Mach 7.95 around a cone at different incidence angles. The circumferential pressure distribution is compared with the experimental data. The cross-sectional Mach number contours are also presented. It is shown that in addition to the outer shock, a cross-flow shock wave is also present in the flow field. The cases of supersonic turbulent flows with Mach number 3 around a tangent-ogive with incidence angles of 6° and a secant-ogive with incidence angles of 10° are also studied. The circumferential pressure distributions are compared with the experimental data and the Euler code results and good agreement is obtained. The cross-sectional Mach number contours are also presented. It is shown that in this case also in addition to the outer shock, a cross-flow shock wave is also present at the incidence angle of 10°.

scholarly journals Experimental Study on the Energy-Release Characteristics of Fine-Grained Fe/Al Energetic Jets under Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3317
Author(s):  
Li ◽  
Du
Keyword(s):  
Experimental Data ◽  
Energy Release ◽  
Impact Energy ◽  
Impact Loading ◽  
Energetic Materials ◽  
Chemical Properties ◽  
Microscopic Analysis ◽  
Specific Content ◽  
Fine Grained ◽  
The Impact

The energy released by the active metal phase in fine-grained Fe/Al energetic materials enables the replacement of conventional materials in new types of weapons. This paper describes an experiment designed to study the energy-release characteristics of fine-grained Fe/Al energetic jets under impact loading. By means of dynamic mechanical properties analysis, the physical and chemical properties of Fe/Al energetic materials with specific content are studied, and the preparation process is determined. The energy-release properties of fine-grained Fe/Al jets subject to different impact conditions are studied based on experimental data, and energy-release differences are discussed. The results show that for fine-grained Fe/Al energetic materials to remain active and exhibit high strength, the highest sintering temperature is 550 °C. With increasing impact energy, the energy release of fine-grained Fe/Al energetic jets increases. At an impact-energy threshold of 121.1 J/mm2, the chemical reaction of the fine-grained Fe/Al energetic jets is saturated. The experimental data and microscopic analysis show that when the impact energy reaches the threshold, the energy efficiency ratio of Fe/Al energetic jets can reach 95.3%.

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