Simple Detonation Research Articles

A Framework for Exploring Nuclear Physics Sensitivity in Numerical Simulations

We describe the AMReX-Astrophysics framework for exploring the sensitivity of astrophysical simulations to the details of a nuclear reaction network, including the number of nuclei, choice of reaction rates, and approximations used. This is explored by modeling a simple detonation with the Castro simulation code. The entire simulation methodology is open-source and GPU-enabled.

Detonation Velocity Measurements Using Rare-Earth Doped Fibres.

In this paper, a simple detonation velocity measurement scheme is presented, which exploits the length-dependent amplified spontaneous emission (ASE) power emitted by off-the-shelf Er-doped fibres. This measurement scheme is first calibrated using cutback tests, so that minimal processing is required between data collection and velocity readout. We then demonstrate the use of this method in an explosive cylinder test and achieve a spatial resolution of approximately ±2 mm, owing to its implementation in a helical geometry. Alongside the standard Er fibres, a specially made, high-concentration Er/Yb-doped fibre is also calibrated, which demonstrates a potential spatial resolution approaching ±20 m.

Investigation of Energetic Particle Distribution from High‐Order Detonations of Munitions

AbstractMilitary training with munitions containing explosives will result in the deposition of energetic materials on ranges. These residues contain compounds that may result in human health impacts when off‐range migration occurs. Models exist that predict the spatial and mass distribution of particles, but they have proven to be difficult to apply to detonating munitions. We have conducted a series of tests to determine if modelling results can be directly applied to simple detonation scenarios. We also command detonated several rounds to obtain an initial indication of high‐order detonation particle distributional heterogeneity. The detonation tests indicate that particle distributions will be quite heterogeneous and that the model used did not adequately describe the distribution of detonation residues. This research will need to be expanded to build an empirical database sufficient to enable the refinement of existing models and improve their predictions. Research on low‐order detonations should be conducted as low‐order detonations will result in higher mass deposition than high‐order detonations. Distribution models verified with empirical data may then be incorporated into range management models.

Pulse Detonation Assessment for Alternative Fuels

The higher thermodynamic efficiency inherent in a detonation combustion based engine has already led to considerable interest in the development of wave rotor, pulse detonation, and rotating detonation engine configurations as alternative technologies offering improved performance for the next generation of aerospace propulsion systems, but it is now important to consider their emissions also. To assess both performance and emissions, this paper focuses on the feasibility of using alternative fuels in detonation combustion. Thus, the standard aviation fuels Jet-A, Acetylene, Jatropha Bio-synthetic Paraffinic Kerosene, Camelina Bio-synthetic Paraffinic Kerosene, Algal Biofuel, and Microalgae Biofuel are all asessed under detonation combustion conditions. An analytical model accounting for the Rankine-Hugoniot Equation, Rayleigh Line Equation, and Zel’dovich–von Neumann–Doering model, and taking into account single step chemistry and thermophysical properties for a stoichiometric mixture, is applied to a simple detonation tube test case configuration. The computed pressure rise and detonation velocity are shown to be in good agreement with published literature. Additional computations examine the effects of initial pressure, temperature, and mass flux on the physical properties of the flow. The results indicate that alternative fuels require higher initial mass flux and temperature to detonate. The benefits of alternative fuels appear significant.

A simple detonation technique to synthesize carbon-coated cobalt

Abstract Cobalt naphthenate and cyclo-1,3,5-trimcthylene-2,4,6-trinitramine (RDX) were used to synthesize carbon-coated cobalt with detonation technique. The reaction was initiated by an electric blasting caps in a vacuum explosion vessel. The detonation soot obtained from the inner wall of the vessel was characterized by XRD, TEM, Raman spectroscopy and vibrating sample magnetometer. XRD pattern indicated that well-crystallized fcc-Co nanoparticles existed in the detonation soot and the average grain size was 30 nm. TEM images showed that the detonation soot consisted of cobalt cores and carbon shells in the form of core–shell structure. Additionally, it also revealed that the nanoparticles were well dispersed after the reaction. Raman spectra gave the information that two carbon phases existed in the products. The magnetic hysteresis curve demonstrated that the prepared nanoparticles exhibited superparamagnetism. The results of the experiment proved that detonation technique offered a simple and energy-saving way for synthesizing carbon-coated cobalt.

Review of Multiscale Modeling of Detonation

Issues associated with modeling the multiscale nature of detonation are reviewed, and potential applications to detonation-driven propulsion systems are discussed. It is suggested that a failure of most existing computations to simultaneously capture the intrinsic microscales of the underlying continuum model along with engineering macroscales could in part explain existing discrepancies between numerical predictions and experimental observation. Mathematical and computational strategies for addressing general problems in multiscale physics are first examined, followed by focus on their application to detonation modeling. Results are given for a simple detonation with one-step kinetics, which undergoes a period-doubling transition to chaos; as activation energy is increased, such a system exhibits larger scales than are commonly considered. In contrast, for systems with detailed kinetics, scales finer than are commonly considered are revealed to be present in models typically used for detonation propulsion systems. Some modern computational strategies that have been recently applied to more efficiently capture the multiscale physics of detonation are discussed: intrinsic low-dimensional manifolds for rational filtering of fast chemistry modes, and a wavelet adaptive multilevel representation to filter small-amplitude fine-scale spatial modes. An example that shows the common strategy of relying upon numerical viscosity to filter fine-scale physics induces nonphysical structures downstream of a detonation is given.

A hydrodynamical analysis of the burning of a neutron star

The burning of a neutron star by strange matter is analyzed using relativistic combustion theory with a planar geometry. It is shown that such burning is probably neither slow combustion nor simple detonation. Fast combustion without detonation is possible under certain circumstances, but would involve very efficient heat transfer mechanisms. It is found, however, that the burning is most likely absolutely unstable with no well defined burn front.