Simulation of initiation of methane explosion shock wave forecast as safety assessment

Authors

  • A. S. Belikov Dr. Sc. (Tech.), Prof., Ukraine
  • N. N. Nalisko Cand. Sci. (Tech.), Assoc. Prof., Ukraine

Keywords:

shock air wave, gas-air mixture, initiation, numerical calculation, combustion front, reaction promotion.

Abstract

Abstract. Purpose. Increase the safety of work in explosive and fire hazardous areas by establishing the patterns of initiation of airgas mixtures by a shock air wave and their consideration in risk assessment and development of measures to reduce them. Mathematical modeling of the passage of a direct and reflected shock air wave through local accumulations of methane. Methodology. Based on the analysis of known studies on the mathematical modeling of explosive processes in a gaseous medium, the task is to study the process of initiating the explosion of a gas-air mixture by a shock air wave. The problem is solved by performing a numerical experiment of propagation of a shock air wave through a cloud of a gas-air mixture. Results. The solution of the problem is made using the mathematical model of the shock tube. The calculation technique in this model is based on the joint solution of the equations of gas dynamics and the chemical kinetics of combustion of a methane-oxygen mixture in air by a numerical method. To describe the motion of the medium in a cylindrical coordinate system, the Euler equations (in the divergent form) were used, which are usually used in calculating the flow of a compressible ideal gas and allow discontinuous solutions. The chemical reaction is presented in the form of one gross-scheme (generalized kinetic mechanism). The reaction rate and, accordingly, the heat release were calculated by the Arrhenius equation. The scheme well describes both own and available in the literature experimental data on the ignition of methane in shock waves in the range of excess pressure in the front of the shock wave from 1.4 to 3 MPa. Scientific novelty. Visible initiation effects have shown a strong influence of gas dynamics on the kinetics of chemical reactions of explosive combustion, which corresponds to the thermal mechanism of ignition and the transition of combustion to detonation. Practical value. Numerical experiments revealed regularities in the initiation of local methane accumulations, which make it possible to increase the efficiency of the method for calculating safe distances and shock loads on building structures during emergency explosions.

Author Biographies

A. S. Belikov, Dr. Sc. (Tech.), Prof.

Department of  Vital Activity Safety, State Higher Education Establishment «Pridneprovsk State Academy of Civil Engineering and Architecture», 24-A, Chernishevskogo st., Dnipropetrovsk 49600, Ukraine, phone +38 (0562) 47-16-01

N. N. Nalisko, Cand. Sci. (Tech.), Assoc. Prof.

Department of  Vital Activity Safety, State Higher Education Establishment «Pridneprovsk State Academy of Civil Engineering and Architecture», 24-A, Chernishevskogo str., Dnipropetrovsk 49600, Ukraine, phone +38 (0562) 47-16-01

References

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Published

2017-04-28

Issue

Section

Energy, ecology, computer technology in construction