Interaction Of Detonation Wave Research Articles

Overlapping effect of detonation driving during multi-point initiation

Employing multi-point initiation in warhead structures produces a detonation wave aiming warhead. Numerous studies have concentrated on enhancing the velocity and analyzing its distribution in this type of warhead. Researchers have developed formulas for the velocity distribution of asymmetrically one-line initiated warheads; however, a reliable and complete calculation method for the velocity distribution in asymmetrically two-line initiated warheads is yet to be established. A new idea is proposed and verified in this work: the velocity distribution for the asymmetric two-line initiation can be derived from that of the one-line initiation. Initial efforts include conducting experimentally verified numerical modeling to examine the propagation and interaction of detonation waves in asymmetrically two-line initiated warheads. Subsequently, using the principle of independent propagation, a model is formulated to use the velocity distribution from asymmetric one-line initiation to predict that of asymmetric two-line initiations. Finally, arena tests are performed to corroborate the overlapping model. This research can provide valuable insights for lethality assessment, protection design, and security analysis.

NUMERICAL STUDY OF THE GAS DETONATION ATTENUATION IN THE ACETYLENE-AIR MIXTURE

The computational technology was created for modeling the attenuation of a cellular detonation during the interaction of detonation waves with a rigid permeable barrier in flammable mixtures based on the ANSYS Fluent package. The reduced kinetic mechanism of acetylene combustion in air was verified using known experimental data. The interaction of detonation waves with a rigid permeable barrier was simulated. The dependencies of detonation attenuation modes on the geometric parameters of the obstacles were determined. Criteria for successful failure and preventing the re-initiation of detonation were identified. The contribution of the considered geometric parameters of the barrier to the attenuation of detonation is estimated. A comparison of the results obtained for acetylene-air and hydrogen-air mixtures was carried out.

The interaction of detonation waves by multipoint initiation under small-size charge condition

In this paper, exploding foil overpressure actuator was used to experimentally study the law of detonation wave collision in small-size charge conditions. In order to quantitatively study the growth, propagation, and duration of the ultrahigh-pressure phenomenon created by the detonation wave collision, photon doppler velocimetry was used to measure the pressure value of the detonation waves. And, further tests were conducted to isolate and measure the duration and pressure trend of this phenomenon by height gradient experiments. Meanwhile, the influence of two-point initiation and four-point initiation on the ultra-pressure value were compared. The results indicated that with the increase of explosive height, the colliding wave would undergo a regular oblique reflection to Mach reflection and finally to attenuation. This paper lays a foundation for the multipoint initiation of insensitive explosive and shaped charge.

Investigation of Heterogeneous Detonation Wave Interaction with Porous Medium

ABSTRACT Mathematical model of aluminum heterogeneous detonation interaction with inert porous media was developed. Main regimes of interaction of heterogeneous detonation wave of stoichiometric mixture of aluminum particles in oxygen with porous inserts were studied. One- and two-dimensional calculations for micron and submicron particles and comparison of these calculations were made. Main regimes of detonation interaction with porous zone and critical conditions of detonation attenuation in porous zones were obtained. Calculations show that for micron particles reducing the diameter of burning particles lead to increasing the volume concentration of inert phase in the porous body that needs for detonation attenuation. Main difference of the propagation regimes for micron and submicron aluminum particles was found.

Detonation driving rules for cylindrical casings under asymmetrical multipoint initiations

The detonation wave–aiming warhead can effectively enhance the lethality efficiency. In the past, rules for casing rupture and velocity distribution under asymmetrical initiations were not adequately investigated. In this study, X-ray photography and numerical modelling are used to examine the casing expansions under centre point, asymmetrical one-point, and asymmetrical two-point (with central angles of 45° and 90°) initiations. The results indicate that early casing ruptures are caused by local high pressures, induced by the initiation, detonation wave interaction, and Mach wave onset. The fragment shapes are controlled by the impact angle of the detonation wave. The fragment velocity distributions differ under different initiation types, and the end rarefaction waves can affect the velocity distribution. This study can serve as a reference for the design and optimization of high-efficiency warheads.

Reacting condensed phase explosives in direct contact

In this article, we present a new formulation and an associated algorithm for the simultaneous numerical simulation of multiple condensed phase explosives in direct contact with each other, which may also be confined by (or interacting with one or more) compliant inert materials. Examples include composite rate-stick (i.e., involving two explosives in contact) problems, interaction of shock waves with chemically active particles in condensed-phase explosives, and devices such as detonators and boosters. There are several formulations that address the compliant or structural response of confiners and particles due to detonations, but the direct interaction of explosives remains a challenge for most formulations and algorithms. The proposed formulation addresses this problem by extending the conservation laws and mixture rules of an existing hybrid formulation (suitable for solving problems involving the coexistence of reactants and products in an explosive mixture and its immiscible interaction with inert materials) to model the interaction of multiple explosive mixtures. An algorithm for the solution of the resulting system of partial differential equations is presented, which includes a new robust method for the retrieval of the densities of the constituents of each explosive mixture. This is achieved by means of a multi-dimensional root-finding algorithm, which employs physical as well as mathematical considerations in order to converge to the correct solution. The algorithm is implemented in a hierarchical adaptive mesh refinement framework and validated against results from problems with known solutions. Additional case studies demonstrate that the method can simulate the interaction of detonation waves produced by military grade and commercial explosives in direct contact, each with its own distinct equation of state and reaction rate law.

2D numerical study on the deflection of thin steel plate subjected to gaseous detonation wave interaction

An elaborate numerical study with a validated LS-DYNA® immersed boundary method fluid-solid interaction code is used to characterize the influence of pre-detonation pressure, ignition point location and time duration on plastic deformation of thin steel plates subjected to hydrogen-oxygen gaseous detonation. Simulation relies on the modeling of detonation by chemical reaction kinetic and its propagation by conservative element solution element solver. Immersed boundary method is used to simulate the interface motion between the detonating gas and the deforming plate to facilitate the assessment of fluid pressure distribution on the plate surface. The numerical tool relates the pressure distribution and gaseous detonation parameters to the plate macroscopic deformation by employing multi-species reactive Euler's equations for the gas and assuming a Johnson-Cook material model for the plate. The numerical model simulated the experimental tests and a good agreement between them was obtained where specific features of gas detonation-driven forming were considered. With the confidence of the validation, the numerical model investigated the effects of different parameters such as the gaseous mixture initial temperature and combustion cylinder longitudinal capacity on overpressure-time history and strain-time history. It is demonstrated that the larger longitudinal capacity of combustion cylinder and more distant ignition point location have a great influence on increasing the detonation wave intensity. Eventually, the rate-dependent Johnson-Cook failure criterion was used to assess the failure state of plate under high-intensity detonations.

Physical and mathematical modeling of interaction of detonation waves with inert gas plugs

In the paper the physical and mathematical model for the description of the processes of transition, attenuation and suppression of detonation in hydrogen-air mixture in one- and two-dimensional formulation, taking into account reduced and detailed kinetics of chemical transformations in reactive gases, by inert gas plugs was proposed. On the basis of this model calculations of the interaction of plane (in one-dimensional formulation) and cellular (in two-dimensional formulation) detonation wave propagating in hydrogen-air mixture with layer of inert gases (argon, nitrogen, carbon dioxide) were performed. It was shown that depending on the type of isolating gas and the length of the plug various flow regimes were realized after the shock wave exits from the inert gas plug: a) reinitiation of detonation wave; b) suppression of the detonation wave with the formation of a deflagration wave at the end of the inert gas plug; c) suppression of the detonation wave with the combustion zone isolation by inert gas plug. The geometric limits of detonation (minimum inert gas plug length leads to detonation suppression with combustion zone isolation) for all three types of inert gas plugs were calculated. Comparison of the effectiveness of detonation suppression by various inert gas plugs shows that the carbon dioxide is more efficient for suppressing the detonation wave, i.e. geometric limits of detonation during interaction of detonation with carbon dioxide plug is smallest compared with other two types of plugs.

Двумерное моделирование ослабления детонационной волны при ее прохождении через область с круговыми препятствиями

The results of numerical simulation of the detonation wave interaction with a circular obstacles staggered are presented. The calculations were carried out for a prepared stoichiometric hydrogen-air mixture. The influence of the rows number, the step between them and the scale effects on the detonation suppression was investigated. The modes of detonation suppression and re-initiation were obtained.

A study on fracture of metal plate under the detonation wave interaction

In this paper, the response of metal plates under the interaction of detonation wave is studied experimentally and numerically. Detonation wave interaction experiments were carried out on metal plates of different materials and thicknesses, and different results such as incision, partial fracture and complete fracture were obtained. ALE algorithm and fluid−solid coupling mode were used to simulate the conditions similar to experiments, and the fracture process and pressure distribution of the metal plate were analyzed. The experimental results were in good agreement with the simulation results. Finally, based on the micro-element fracture theory, the theoretical analysis of the fracture law of the metal plate was carried out, and the fracture criterion based on the threshold impulsive velocity was concluded. It has been verified that this criterion is in good agreement with the simulation and experimental results. It can be used as a basis for estimating the fracture problem of metal plates under explosive load.

Fundamental studies of explosion arrester mitigation mechanisms

We report the results of laboratory investigations of the behaviour during explosion mitigation by channels typical of those used in commercial explosion arrester devices. Experimental results are presented first of shock and detonation wave interaction with a miniaturized matrix of narrow channels aligned parallel to the incoming flows. The results with a larger scale device using the same channel dimensions tested at more extreme conditions representative of overdriven detonation certification test conditions are consistent with the reduced scale laboratory measurements. To evaluate the applicability of laboratory scale evaluation of arrester elements for other types of explosion arrester, a further preliminary study is also reported with deflagration arrester elements. Finally, the present observations are interpreted in the light of published theories potentially relevant to explaining successful explosion mitigation, or otherwise, by commercial arrester devices. Using this approach, laboratory scale measurements are shown to be as a useful tool for investigating the dominant explosion mitigation mechanisms relevant to practical end user application safety devices and provide an opportunity for assisting with the design and evaluation of practical explosion, especially designs that could be supported by more comprehensive detailed CFD simulations where the supporting laboratory test configurations could also facilitate the use of more sophisticated diagnostic methods

Effects of Detonation Waves Asymmetric Collision

In this article, Effects of detonation waves asymmetric collision was studied. Through theoretical calculation, the position of detonation waves collision was shown. And it is found by numerical simulation that the pressure of detonation waves interaction decreases wave-likely following the initiation delay time increasing, but still exceed the pressure of the place where there is no interaction of detonation waves. The pressure-enhancing effects of detonation wave interaction can be used to achieve the energy accumulation.

Effect of Inert Micro- and Nanoparticles on the Parameters of Detonation Waves in Silane/Hydrogen–Air Mixtures

Physicomathematical modeling of interaction of detonation waves in silane/hydrogen composite mixtures with clouds of inert micro- and nanoparticles ranging from 10 nm to 100 µm is performed. The normalized detonation velocity is calculated as a function of the volume concentration of particles. It is found that the efficiency of detonation suppression increases only as the particle diameter decreases to 1 µm. The influence of the thermodynamic parameters of particles on the detonation suppression efficiency is identified. The concentration limits of detonation are determined. It is demonstrated that a certain equilibrium asymptotic level of the concentration limits of detonation is reached as the particle diameter decreases below 1 µm. An approximation of the concentration limits of detonation is obtained in the form of an analytical dependence of the limiting volume concentration of particles on their diameter and fuel concentration in a composite two-fuel mixture of silane, hydrogen, and air.

Mechanics of Plate Fracture from Detonation Wave Interaction

AbstractThe interaction of detonation waves was widely used in warhead design due to its ability to generate local high‐pressure regions. In this paper, the detonation interaction was investigated by experiments and finite element (FE) models. Experiments were conducted first to capture the fundamental dynamic fracture and fragmentation patterns and they served as a basis of validation for both the FE and analytical models. According to fracture surface, shear fracture is prior mechanism for steel‐plate fragmentation. The FE results indicated the dynamic fracture of steel plate was referred to the pressure difference between the collision area and its adjacent areas. A theoretical analysis of detonation wave interaction in explosive was carried out, and the relationship between the pressure at the collision area and adjacent areas was obtained. In the discussion part, the influencing factors and the optimal results for the plate fracture in the simulation calculation were carried out.

Physical and mathematical modeling of interaction of detonation waves in mixtures of hydrogen, methane, silane, and oxidizer with clouds of inert micro- and nanoparticles

ABSTRACTThe physical and mathematical models for the description of the detonation process in mixtures of hydrogen–oxygen, methane–oxygen, and silane–air in the presence of inert nanoparticles were proposed. On the basis of these models, the dependencies of detonation wave (DW) velocity deficit versus the size and concentration of inert nanoparticles were found. Three regimes of detonation flows in gas suspensions of reactive gases and inert nanoparticles were revealed: (1) stationary propagation of weak DW in the gas suspension, (2) galloping propagation of detonation, (3) destruction of the detonation process and transformation to wave of turbulent burning. It was determined that the mechanisms of detonation suppression by micro- and nanoparticles are closed and lie in the splitting of a DW to frozen shock wave and ignition and combustion wave. Concentration limits of detonation were calculated. It turned out that concentration limits (on particle volume concentration) of detonation are quite similar for particles with diameters ranging from 10 nm to 1 µm.

Experimental and numerical investigations on propagating modes of detonations: Detonation wave/boundary layer interaction

In the present work the propagating modes of detonation wave in supersonic hydrogen–air mixtures are investigated in narrow rectangular channels. To clarify the effect of the detonation wave interaction with the boundary layer on the evolution and propagation of detonation phenomenon, high-speed laser schlieren experiments and adaptive Navier–Stokes (NS) simulations (pseudo-DNS) combined with a detailed reaction model are performed. The experimental results show that after successful ignition, two propagating modes are observed and can be classified as Oblique shock-induced combustion/Mach stem-induced detonation (OSIC/MSID) and pure Oblique shock-induced combustion (OSIC). For the OSIC/MSID mode, a Mach stem induced overdriven detonation is generated in the middle of the main flow. For the pure OSIC mode, no detonation wave but two oblique shock-induced combustion regions are generated throughout the whole channel with the overall structure taking a thwartwise V shape. The OSIC/MSID and pure OSIC propagation modes are further confirmed by pseudo-DNS employing a detailed reaction model and dynamic adaptive mesh refinement for the same conditions as utilized in the experiments. The numerical results show that because of subsonic combustion near the walls induced by the boundary layers, the OSIC/MSID is not entirely symmetrical, while for the pure OSIC mode, larger fluctuations are observed along the oblique shock waves resulting from enhanced instabilities due to additional chemical heat release.

Mathematical modeling of the detonation wave and inert particles interaction at the macro and micro levels

Calculation technology for modelling of two-dimensional detonation flows in a system of the reacting gas mixture-inert particles has been developed. The problems associated with the cellular detonation suppression are researched. The interaction of the detonation wave with inert particles is modeled using the macro and micro approaches. First, the interaction with Al2O3 particles with a diameter of 100 μm and 1 mm at the macro level was investigated using a continuum approach. Values of the volume concentration resulting in a change of the detonation cell size, weakening of the detonation wave, and suppression detonation are obtained. Secondly, a simulation of the detonation wave interaction with particles at the micro level has been carried out. A wave structure of the flow near the particles is obtained and the mechanism of detonation suppression was shown at volume concentrations of particles close to those obtained in modeling at the macro level.

Numerical Modeling Of The Ignition Initiation In The Scramjet Combustion Chamber Via Detonation

The paper studies of the cellular detonation wave interaction with supersonic reacting flow in the scramjet combustion chamber. Comparing the flow fields for the details and the reduced chemical kinetics models is allowed verifying the acceptability of the proposed simplified kinetic scheme. The possibility of using pulsating detonation for the ignition intensification in the scramjet combustion chamber is shown. Calculation of the detonation wave interaction with nonpremixed hydrogenair mixture is made. The ability to influence on the hydrogen-air mixing process by means of detonation tube is detected. The effect of tube sizes to intensification of hydrogen air mixing in the flow at channel with a cavity is calculated.

Recovery and suppression of the detonation of hydrogen-air mixtures at an obstacle with orifices

A numerical simulation of the interaction of detonation waves with an obstacle having orifices and an analysis of the results were performed. The calculations were conducted using the 3D GasDynamicTool code for a model gas with parameters of detonation corresponding to a hydrogen-air stoichiometric mixture under normal conditions. Within the framework of the assumptions made, it was shown that, upon interaction with a perforated partition, a detonation wave experiences disintegration accompanied by the formation of unsteady jets of detonation products, with each one being preceded by a shock wave. The simulations demonstrated that the reinitiation of detonation downstream from the partition is determined by the dynamics of the ignition caused by the interaction between the converging shock waves formed ahead of the jets outflowing from neighboring orifices.

Simulation of detonation wave interaction using an ignition and growth model

A kinetics based detonation model has been integrated with an existing object oriented hydrocode. The model has been demonstrated to correctly predict the shock initiation of explosives and captures key features such as the von Neumann pressure spike and reaction zone. Comparisons to experimental flyer plate data for both primary and secondary class explosives have been performed and key features such as detonation wave form and resulting target disk velocities are reproduced. Simulations have also been performed representing the interaction of various mechanical waves. First, the interaction of detonation waves, a key process in energetic systems, is simulated. Next, the response of an established detonation wave to an explosive that has been preconditioned by a weak compression wave is modeled. These have been carried out to determine the utility of the existing kinetic schemes for such problems.