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Showing 2 results for Gaseous Detonation
Saeed Parvar, Kiumars Mazaheri,
Volume 15, Issue 1 (3-2015)
Abstract
Numerical simulation of gaseous detonation is one of the most challenging problems in computational fluid dynamics (i.e., CFD). The presence of sonic locus at the end of the reaction zone isolates the reaction zone and the leading shock from the far-field flow perturbations, so computational domain may be truncated by artificial boundary conditions. However, some artificial boundary conditions generate spurious waves that introduce some errors into the results. The computational domain is usually considered very large for protecting the domain from spurious waves. A systematic study of boundary conditions’ role in simulation of self-sustained detonation has not been performed yet. In the present study, it is aimed to investigate the influence of the width and length of the computational domain on numerical simulation and the effect of activation energy on the length and width of the domain. Instead of considering a very large domain, the so-called non-reflecting boundary condition is implemented in the present investigation. Characteristics method was employed to define the non-reflecting boundary conditions. Finite length of domain was computed for 1D and 2D simulations. Suitable length of the domain was determined for different activation energies. The results indicate that the suitable length and width of the domain for high activation energy mixtures are larger with respect to the corresponding length and width for low activation energy mixtures. Results also show that, using non-reflecting boundary condition, the computational time decreases considerably for both one and two-dimensional simulations.
Mojtaba Haghgoo, Hashem Babaei, Tohid Mirzababaie Mostofi,
Volume 21, Issue 11 (9-2021)
Abstract
Numerical simulation of Eulerian fluid Lagrangian solid interaction incorporating H2-O2 mixture gas detonation plate forming by employing conservative element and solution element immersed boundary method in LS-DYNA software is proposed in this paper. The detonation mechanism includes 7 species and 16 reactions. The chemical reaction mechanism and detonation wave propagation of Eulerian solver and dynamic plastic response of mild steel thin plate of Lagrangian solver are discussed thoroughly. The Johnson-Cook phenomenological material model with failure criterion is used to provide accurate predictions of dynamic response and failure state of detonation loaded steel plates taking into account material strain-rate sensitivity and non-linearities. The 2D numerical model is validated by comparing the simulation results with experimental data for thickness strain. The simulated pressure-time history of combustion cylinder, von Mises stress and deflection pattern of plate are also represented. Furthermore, a series of numerical simulation was carried out to determine the effect of the magnitude of internal detonation pressure on plate, taking into account different combustion cylinder longitudinal capacities, pre-detonation pressures and ignition point locations. Results show that an increase of pre-detonation pressure is conducive to increase the value of maximum detonation pressure while decreasing the combustion duration. Moreover, combustion cylinder with higher longitudinal capacity is more powerful to deform the plate.