scholarly journals Explosion waves and shock waves III-The initiation of detonation in mixtures of ethylene and oxygen and of carbon monoxide and oxygen

1935 ◽  
Vol 152 (876) ◽  
pp. 418-445 ◽  
Author(s):  
William Payman ◽  
H. Titman ◽  
Jocelyn Field Thorpe
Keyword(s):  
Shock Wave ◽  
Carbon Monoxide ◽  
Shock Waves ◽  
Detonation Wave ◽  
Wave Speed ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
And Shock Waves ◽  
Long Run ◽  
Detonating Gas

This series of papers has so far dealt mainly with non-maintained or partially maintained atmospheric shock waves, and only incidentally with the fully maintained "detonation" wave. It is generally accepted that the detonation wave in an explosive gas mixture is a shock wave produced by the rapid combustion of the mixture, sufficiently intense to cause almost instantaneous ignition of the gas through which it passes, and continuous maintained by the combustion thereby started. An account of some preliminary experiments, using the "wave-speed" camera to record the movement of the flame and of the invisible shock waves in front of the flame in gas mixtures prior to detonation, has already been given by one of us. Those experiments related mainly to hydrogen-oxygen and methane-oxygen mixtures whose aptitude to detonate may be regarded as moderate, for the continuation of the work, mixtures with oxygen have again been used, but a more readily detonating gas, ethylene, was chosen. Experiments were also made with carbon monoxide, because the flame usually requires a comparatively long run before detonation is established. These two gases have the advantage, not shared by hydrogen and methane, that their predetonation flames are sufficiently actinic for good records to be obtained by direct photography for comparison with corresponding "wave-speed" records. All gas mixtures used were saturated with water vapour.

scholarly journals Explosion waves and shock waves. IV—Quasi-detonation in mixtures of methane and air

1937 ◽  
Vol 158 (894) ◽  
pp. 348-367 ◽  
Keyword(s):  
Shock Waves ◽  
Detonation Wave ◽  
Practical Importance ◽  
Coal Mines ◽  
Maximum Speed ◽  
Theoretical Interest ◽  
Rapid Motion ◽  
And Shock Waves ◽  
Effects Of Violence

The possibility of detonation in mixtures of methane and air, apart from its theoretical interest, is of practical importance in connexion with the study of explosions in coal mines. Many attempts have been made experimentally to increase the violence of explosion or the intensity of combustion of mixtures of methane and air to see if speeds of flame and effects of violence comparable with those of detonation could be obtained. Mason and Wheeler noted that restrictions in the path of an explosion accelerated the flame, and observed that as the flame of a methane-air mixture passed through the second of two restrictions placed in a 30·5-cm. tube “the development of the detonation wave appeared imminent”. The experiments were continued by Chapman and Wheeler, who obtained a maximum speed of 420 metres per second beyond the restricted section of a tube 5 cm. in diameter. The effect of the restrictions was in their opinion to induce rapid motion in the mixture through which the flame was travelling.

On Generation of Ultra-High Pressure by Converging of Underwater Shock Waves

1998 ◽  
Vol 120 (1) ◽  
pp. 51-55 ◽  
Author(s):  
S. Itoh ◽  
S. Kubota ◽  
S. Nagano ◽  
M. Fujita
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Simulation Method ◽  
Ceramic Materials ◽  
Underwater Shock Wave ◽  
Water Chamber ◽  
Metallic Compounds ◽  
Underwater Shock ◽  
Graph System

The characteristics of a new assembly for the shock consolidation of difficult-to-consolidate powders, such as inter-metallic compounds or ceramic materials, were investigated by both the experimental method and numerical simulation method. The assembly consists of an explosive container, a water chamber, and a powder container. Once the explosive is detonated, a detonation wave occurs and propagates, and then impinges on the water surface of the water chamber. After that, there occurs immediately an underwater shock wave in the water chamber. The underwater shock wave interacts with the wall of the chamber during its propagation so that its strength is increased by the converging effect. We used the usual shadow graph system to photograph the interaction process between detonation wave and water. We also used a Manganin piezoresistance gage to measure the converged pressure of the conical water chamber. Finally, we numerically investigated, in detail, the converging effects of the various conical water chambers on the underwater shock waves. The experimental results and the correspondingly numerical results agree quite well with each other.

scholarly journals Explosion waves and shock waves. Part I.—The wave-speed camera and its application to the photography of bullets in flight

1931 ◽  
Vol 132 (819) ◽  
pp. 200-213 ◽  
Keyword(s):  
Shock Waves ◽  
Wave Speed ◽  
Glass Tube ◽  
Horizontal Line ◽  
Photographic Method ◽  
Explosive Mixture ◽  
Horizontal Movement ◽  
Late Professor ◽  
Short Columns ◽  
And Shock Waves

Photographic Methods for Measuring Velocities .—Two methods have been used to determine rates of detonation in gases, the chronographic method first used by Berthelot and Vieille and the photographic method of Mallard and Le Chatelier. The second method has proved the more useful in practice and, as developed by the late Professor H. B. Dixon, has been adopted almost universally by other workers. Not only has it the advantage that it provides a means of measuring the rate of detonation in short columns of gas, but it also allows the after movements of the flame and gases to be analysed. The method makes use of a revolving drum around which a sensitised film is wrapped. A camera lens gives an image of the horizontal glass tube containing the explosive mixture as a horizontal line across the width of the film. As the drum rotates on its horizontal axis, the film has a motion which is sensibly vertical at the focus of the lens, so that the image records an inclined trace compounded of the horizontal movement of the flame and the vertical move­ment of the film.

scholarly journals Effects of Reversed Shock Waves on Operation Mode in H2/O2 Rotating Detonation Chambers

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8296
Author(s):  
Yanliang Chen ◽  
Xiangyang Liu ◽  
Jianping Wang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Operation Mode ◽  
Wave Number ◽  
Mode Switching ◽  
Rotating Waves ◽  
Operation Modes ◽  
Rotating Detonation

Operation modes are an important topic in the research of Rotating Detonation Chamber (RDC) as it can affect the stability of RDC. However, they have not been discussed in detail due to the limitation of measurement means in experiments. The aim of this research is to investigate the mechanism of different operation modes by numerical simulation. In this paper, a numerical simulation for RDCs with separate injectors is carried out. Different operation modes and mode switching are analyzed. There is a series of reversed shock waves in the flow field. It was found that they have great effects on operation mode and mode switching in RDCs. A reversed shock wave can transit into a detonation wave after passing through isolated fresh gas region where fresh gas and burnt gas distribute alternatively. This shock-to-detonation transition (SDT) phenomenon will influence the ignition process, contra-rotating waves mode and mode switching in RDCs. SDT makes the number of detonation wave increases, resulting in multi-wave mode with one ignition. Moreover, quenching of detonation waves after collision and SDT after passing through isolated fresh gas region are the mechanism of contra-rotating waves mode in RDCs with separate injectors. In addition, when the inlet total temperature increases, a shock wave is easier to transit into a detonation wave. The distance that a shock wave travels before SDT decreases when temperature increases. This will result in mode switching. Therefore, SDT determines that there is a lower bound of detonation wave number.

Further Properties of the Wave Charts

1962 ◽  
Vol 66 (624) ◽  
pp. 789-792 ◽  
Author(s):  
W. A. Woods
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Wave Speed ◽  
Pressure Waves ◽  
Perfect Gas ◽  
Expansion Waves ◽  
Isentropic Expansion ◽  
Constant State ◽  
Mach Numbers ◽  
Straight Lines

In a previous paper charts were given which related the flow Mach numbers on either side of a wave to a dimensionless wave speed. Charts were given for shock waves, isentropic expansion waves and isentropic non-steep pressure waves in a perfect gas. In this note it is shown that the lines of constant state ratio plotted on the charts constitute families of straight lines; this fact is particularly important in the case of the shock wave chart. The wave domains are also established and compared diagrammatically.

scholarly journals Evolution of the Rayleigh–Taylor instability in the mixing zone between gases of different densities in a field of variable acceleration

2003 ◽  
Vol 21 (3) ◽  
pp. 393-402 ◽  
Author(s):  
S.G. ZAYTSEV ◽  
V.V. KRIVETS ◽  
I.M. MAZILIN ◽  
S.N. TITOV ◽  
E.I. CHEBOTAREVA ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Compression Wave ◽  
Taylor Instability ◽  
Mixing Zone ◽  
Compression Waves ◽  
Accelerated Motion ◽  
And Shock Waves ◽  
Rayleigh Taylor Instability ◽  
Qualitative Distinction

The interaction of the mixing zone between two gases of different densities with compression waves and shock waves has been investigated. The characteristics of the mixing zone in which the Rayleigh–Taylor instability is developing have been analyzed. The evolution of the mixing zone volume and mass during the accelerated motion has been defined. A qualitative distinction in the evolution of the mixing zone under the influence of a continuous deceleration resulting from the interaction with the reflected compression wave—shockless deceleration—is revealed as compared to deceleration that is accompanied by appearance of a shock wave moving through the mixing zone—shock-induced deceleration.

scholarly journals Physics and applications with laser-induced relativistic shock waves

2016 ◽  
Vol 4 ◽  
Author(s):  
S. Eliezer ◽  
J. M. Martinez-Val ◽  
Z. Henis ◽  
N. Nissim ◽  
S. V. Pinhasi ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Bulk Material ◽  
High Irradiance ◽  
Alpha Particles ◽  
Relativistic Shock ◽  
Laser Acceleration ◽  
The Creation ◽  
Special Case

The laser-induced relativistic shock waves are described. The shock waves can be created directly by a high irradiance laser or indirectly by a laser acceleration of a foil that collides with a second static foil. A special case of interest is the creation of laser-induced fusion where the created alpha particles create a detonation wave. A novel application is suggested with the shock wave or the detonation wave to ignite a pre-compressed target. In particular, the deuterium–tritium fusion is considered. It is suggested that the collision of two laser accelerated foils might serve as a novel relativistic accelerator for bulk material collisions.

Simulation of the Effects of Shock Wave Passing on a Turbine Rotor Blade

1985 ◽  
Vol 107 (4) ◽  
pp. 998-1006 ◽  
Author(s):  
D. J. Doorly ◽  
M. L. G. Oldfield
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Shock Waves ◽  
High Frequency ◽  
Guide Vane ◽  
Turbine Rotor ◽  
Surface Boundary ◽  
Suction Surface ◽  
Very High Frequency ◽  
And Shock Waves

The unsteady effects of shock waves and wakes shed by the nozzle guide vane row on the flow over a downstream turbine rotor have been simulated in a transient cascade tunnel. At conditions representative of engine flow, both wakes and shock waves are shown to cause transient turbulent patches to develop in an otherwise laminar (suction-surface) boundary layer. The simulation technique employed, coupled with very high-frequency heat transfer and pressure measurements, and flow visualization, allowed the transition initiated by isolated wakes and shock waves to be studied in detail. On the profile tested, the comparatively weak shock waves considered do not produce significant effects by direct shock-boundary layer interaction. Instead, the shock initiates a leading edge separation, which subsequently collapses, leaving a turbulent patch that is convected downstream. Effects of combined wake- and shock wave-passing at high frequency are also reported.

The initiation of condensed explosives by shock waves from metals

1958 ◽  
Vol 246 (1245) ◽  
pp. 284-288 ◽  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Mild Steel ◽  
Delay Time ◽  
Incident Shock ◽  
Shock Strength ◽  
Solid Explosive ◽  
Condensed Explosives

When a shock wave is transmitted from a metal to a solid explosive a pure shock wave is transmitted into the explosive. The shock generally builds up to a complete detonation wave but in some cases it fails to initiate the explosive. In the former case an effective delay time in the initiation of the explosive is observed. Initiation delays have been measured in 2 in. diam. sticks of 60/40 RDX/TNT as a function of incident shock strength in mild steel and aluminium .

Numerical Analysis of Behavior on Opposing Unsteady Supersonic Jets in a Flow Field with Shields

2018 ◽  
Vol 910 ◽  
pp. 96-101 ◽  
Author(s):  
Toshiki Kinoshita ◽  
Hiroshi Fukuoka ◽  
Ikurou Umezu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pulsed Laser ◽  
Supersonic Jets ◽  
Collision Dynamics ◽  
Ansys Fluent ◽  
And Shock Waves ◽  
Pass Through ◽  
Background Gas ◽  
Volume Method

Collision dynamics of opposing unsteady supersonic jets injected in background gas with shock waves were calculated to simulate double pulsed laser ablation. Since the jets are deflected by collision and the motion of debris is ballistic. This characteristic can be used to reduce the number of debris when shields are mounted in front of substrate. The flow of jets through installed shields is complicated by the interaction between shields and jets, and between shields and shock waves. We investigate influence of shield position on the shock waves and the jets by numerical calculations. Axisymmetric two-dimensional compressible Euler equations were solved using the finite volume method by using ANSYS Fluent 14.0.0 code. The shields with slit was mounted parallel to the direction of initially injected jets. In order to investigate the influence of shield position on the shock waves and the jets, the shield position and background gas pressure were adopted as parameters. The jets and shock wave are deflected by collision and they can pass through the slit of shields. The passed shock wave reflects at the substrate mounted behind the slits and it forces back the jet to decrease the jet velocity. The shield position governs the velocity and amount of the jet that reach the substrate.

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