Numerical Evaluation of Probability of Harmful Impact Caused by Toxic Spill Emergencies

The purpose of the work is to assess the degree of inhalation damage of a person exposed to the toxic cloud of liquefied gas evaporation from a spill spot of various shapes. The mathematical model of liquefied gas spill evaporation which arose as a result of accidental destruction of the storage capacity and further dispersion of the gas impurity in the atmosphere surface layer was developed. The computational technology for determining the fields of conditional probability of human inhalation damage by a toxic gas based on a probit analysis is developed. The mathematical model takes into account the flow compressibility, complex terrain, three-dimensional nature of the dispersion process, and the presence of toxic liquid substance evaporation from the arbitrary spill spot with varying intensity. The model allows obtaining space-time distributions of the toxic gas relative mass concentration and inhaled toxidosis which is necessary to determine the fields of the human damage probability based on the probit analysis. For different ellipticity of the hydrogen cyanide spill elliptical spot the fields of probability of human mortal damage are obtained and the influence of spot ellipticity on the scale of the consequences of an accident of this type is analysed. The developed technology allows carrying out automated analysis and forecasting in the time and space of the damage probability of a person exposed to the toxic gas as an indicator of the safety of the technogenic object.