Control of flow by shock air waves in underground structures

Abstract

Purpose. Development and research of ways to control the propagation of shock air waves due to constructive and planning solutions for the purpose of protecting personnel during emergency explosions, in conditions of preserving the technological section of canals and workings in extended structures. Justification of the parameters of numerical simulation in CFD models of discontinuous internal flow of a gas stream. Methodology. The research was carried out on the basis of search and analysis of publications on the topic of the work, an analysis of the research object was used for the mathematical formulation of the problem and the justification of the boundary conditions and parameters of numerical simulation. To substantiate the rational configurations of the reflecting-wave chambers, an analytical evaluation of the interaction of the shock air-wave front with the backward step, the chamber wall and the concave angle was performed. By numerical simulation, the physical processes controlling the propagation of shock air waves. Findings. An analysis of the physical processes occurring during the control of the propagation of shock air waves with the aid of chambers of reflecting waves made it possible to reveal a number of qualitative and quantitative laws governing the motion of the wave front at the interface with the branch channels. The mechanism of action of a reflecting wave formed in a chamber by a reflected shock wave on a supersonic flow is shown. To effectively control the propagation of strong shock air waves with an excess pressure of more than 0.1 MPa, it is necessary to use chambers reflecting waves with an inclination angle of the reflection surface close to45°. Originality. The parameters of the numerical simulation of the propagation of the shock air wave through the system of reflected waves in the FlowVision modeling environment are substantiated. An analytical evaluation of the parameters of the wave front is made during diffraction of the backward step directly in the chambers of the reflecting waves, movement along its wall and reflection on the inclined surface. The dependence of the effectiveness of controlling the shock air-wave on the parameters of the chambers. Practical value. Reasonable rational parameters of the reflecting wave chambers allow to increase the efficiency of personnel protection from the action of shock air waves in the extended structures of civil defense and mining facilities.