Abstract
<jats:p>В статье рассматривается разработанная отечественными и зарубежными авторами методология оценки техногенных рисков, которая учитывает поражающие факторы, формирующиеся при реализации опасностей на взрывоопасных, пожароопасных и токсичных промышленных объектах. Расчет полей поражающих факторов, возникающих при взрывах, пожарах или образовании токсичного облака, является довольно сложным и важным этапом количественной оценки техногенных рисков. Однако в настоящее время существует большое количество разнообразных методов, которые существенно различаются по точности, сложности и глубине изучения процессов формирования полей поражающих факторов. Использование этих методов исследователями при декларировании промышленной безопасности опасных производственных объектов определяет необходимость их сравнения и всестороннего анализа. В данной статье представлен сравнительный анализ методов, используемых для оценки последствий взрывов дезорганизованных облаков топливно-воздушных смесей горючих веществ. Алгоритм предполагает совместное использование моделей детонации и дефлаграции в зависимости от значения расчетного параметра, определяющего режим взрывного превращения. Результаты расчета хорошо согласуются с методами «СП 12.13130» и «Toksi+Risk». Погрешность определения выходных характеристик ударной волны не превышает 8–12 %.</jats:p> <jats:p>Introduction. According to the requirements of the Order the Federal Environmental, Technological and Nuclear Supervision Service No. 412 dated 28 November 2022 “On approval of the safety manual “Methodology for assessing the consequences of emergency explosions of fuel and air mixtures”, it is necessary to follow the recommendations specified in this Methodology for assessing the parameters of air shock waves during explosions of air-fuel mixtures (hereinafter referred to as AFM), generated in the atmosphere during industrial accidents to ensure the industrial safety requirements of hazardous production facilities; recommendations for determining the likely degrees of damage to people and the degree of damage to buildings from explosive loads in accidents with explosions of clouds of air-fuel mixtures at hazardous industrial facilities. According to the Federal Law No. 123 dated 22 July 2008 “Technical Regulations on Fire Safety Requirements”, fire risk – a measure of the possibility of realizing a fire-hazardous situation and its consequences for both humans and material assets, therefore, in the context of a multiply increased number of “air attacks”, in particular, on petrochemical and fuel and energy facilities. The authors consider it appropriate and timely to supplement the capabilities of the methodology for calculating the magnitude of fire risk at industrial facilities (according to the Order of the EMERCOM of Russia No. 404 dated 10 July 2009 “On Approval of the methodology for determining calculated fire risk values at industrial facilities”) with algorithms for estimating the parameters of air shock waves during explosions of fuel-air mixtures, as the initiator, in the vast majority of cases, a factor in the development of fire-hazardous situations. Goals and objectives. To carry out a detailed analysis of the influence of all the main factors influencing the magnitude of the error in determining the parameters of the damaging factors of the air shock wave during fuel assembly explosions. To show the advantages of expert assessment methods as the most acceptable way to determine the mode of explosive transformation of a fuel assembly cloud, as a result of which, when predicting the consequences of accidents at explosive and fire-hazardous facilities, it is necessary to pre-determine the most likely mode of explosive transformation of a fuel assembly cloud. Methods. Since access to information about the parameters of previous accidents and physical experiments is limited, the only available way to confirm the reliability of mathematical modeling results is through comparative analysis with other similar methods. This methodology is based on the algorithm of the parametric model for calculating the characteristics of air shock waves contained in the Safety Manual (The Order of the Federal Environmental, Technological and Nuclear Supervision Service No. 412 dated 28 November 2022). The high convergence of the results was achieved primarily due to the use of a refined algorithm for calculating shock wave parameters for modeling. Equally important is the correct preparation of the source data. Computational methods are used to determine such physical quantities as saturated vapor pressure, the concentration of a combustible substance in a fuel assembly cloud, the evaporation rate of a combustible liquid, etc. The results and their discussion. The article provides a comparative analysis of the calculation results obtained using existing methods for assessing the consequences of emergency explosions of fuel assembly clouds. The software products «Avariya», «Toxi+Risk», «PB-bezopasnost'», «SP 12.13130-2009» and «PK-412» were subject edto comparative analysis. An analysis of the results of calculations of the radii of damage zones of industrial buildings showed their significant discrepancy both within the framework of the methods themselves and in comparison with the actual data of previous accidents. At the same time, the greatest deviation from the actual and experimental values of the radii of the affected areas is observed when simulating AFM explosions using the software «PB-bezopasnost'». The methodology for determining the radii of damage zones to buildings and structures during explosions, used by the software «PB-bezopasnost'», is based on the “TNT equivalent” model, which does not fully correspond to the real processes occurring in industrial accidents with AFM explosions, which are characterized by deflagration rather than detonation mode of explosive transformation. Also, the methodology does not allow taking into account a number of other important conditions and factors affecting the development and consequences of an explosion, such as the aggregate state of a hazardous substance, the characteristics of the surrounding space and the position of the point of initiation of an explosive cloud. These shortcomings are absent in the methodology for assessing the consequences of emergency explosions used by the software “Toxi+Risk” and “PK-412”. The «PK-412» software package shows a high degree of convergence of the results of calculating damage zones of industrial buildings with the results obtained using the methods “SP 12.13130” and “Toxi+Risk”. Conclusion. To increase the accuracy of determining the parameters of damaging factors in fuel assembly emergency explosions, when determining the mode of explosive transformation of a fuel assembly cloud, the authors proposed to use in calculations the interpolation values obtained from analyzing the situational plan of a specific object instead of the discrete values of the velocity of the visible flame front corresponding to the class of space surrounding the place of ignition of the fuel assembly cloud. This allows for a more complete consideration of the physical and chemical explosive properties of the fuel-air mixture of a combustible substance and, as a consequence, an increase in the accuracy of determining the parameters of damaging factors. The algorithm of the «PK-412» software complex assumes the combined use of detonation and deflagration models, depending on the value of the calculated parameter that determines the mode of explosive transformation. This approach more adequately reflects the physical picture of a detonation and deflagration explosion.</jats:p>