Blast wave dynamics caused by explosion of toroidal cloud of propylene-air mixture

In the paper, a physical and mathematical model is proposed, and the corresponding numerical algorithm is developed to calculate the shock-wave flow, generated by the explosion of a complex-shaped cloud. As an example, we simulate the atmosphere blast of the propylene-air mixture above a flat horizontal surface. The cloud has a shape of tor, which axis makes the 30 degrees angle with the normal to the substrate. Similar clouds can be formed during powerful emergency jet emissions of explosive gas into the atmosphere. Numerical simulation of the problem based on solving of a system of 3D transient Euler equations, supplemented by the transport equations for a two-component gas medium and the energy conservation equation. Gas explosion assumed to be instantaneous. After the explosion, the reaction products are supposed to be in a "frozen"state, and their thermodynamic parameters are calculated by explicit algebraic formulas depending on pressure and temperature. Based on the results of numerical simulation, a complex shock-wave structure of the flow and dynamics of pressure profile in the vicinity of the explosion zone and near the horizontal surface are obtained. Flow picture includes two non-concentric ring shocks and internal expansion wave. Based on the computation results, the complex wave structure is analyzed, and pressure loads on the substrate are evaluated.