Numerical study of shock-wave diffraction in variable-section channels in gas suspensions

Abstract

The problem of shock-wave transition past a backward-facing step in a gas suspension is solved. The calculation method is tested on a similar problem for a pure gas, and good agreement with available experimental and numerical results is reached. The effect of shock-wave intensity, mass load factor of particles in the mixture, and particle size on the flow structure in the gas suspension is determined. It is shown that the greatest difference between the flow pattern in a two-phase mixture and the corresponding flow in a pure gas is observed in the range of times when the characteristic sizes of the structures being formed are commensurable with the scale of the relaxation zones.

Diffraction of a plane detonation wave on a back-facing step in a gas suspension

“…Some similarity with flows of nonreacting gas suspensions can also be noted [6]: vortex zone on the expansion corner, system of shock waves in this region, and region of reduced concentration of particles behind the step. It should also be noted that these vortex structures are common for all regimes of detonation-wave propagation.…”

“…In addition, the wave structure is characterized by the presence of relaxation processes whose scale is also related to the particle size. If the channel width is commensurable with the characteristic relaxation scale, this can lead to qualitative reconstruction of the flow (for shock waves, this phenomenon was demonstrated in [6]) and to possible failure of the detonation process. Therefore, the influence of both the channel width and the particle size was considered.…”

“…For solving equations for discrete components, we used the Jentry-Martin-Daly upstream difference scheme. The method was adapted to solving two-dimensional problems with a complicated geometry and was used to solve problems of diffraction of shock waves in inert gas suspensions [6].…”

“…For this reason, the shock-wave processes can be substantially different from similar processes in gases. Qualitative differences in the flow structure were found, for instance, in the problem of shock-wave diffraction on a backward-facing step in a gas suspension [6].…”