Analysis of parameters of gas dynamic flows in case of emergency explosions

Introduction. This paper is devoted to the issues related to calculations of gas-dynamic flows arising during emergency explosions. The relevance of this publication is due to the following circumstances. The dynamic parameters of explosive loads have a rather wide range, which varies in duration and intensity from several milliseconds and hundreds of atmospheres to several seconds and several percent of the atmosphere, which is determined by the type of explosive phenomenon. In this regard, the overall picture of destruction or post-accident situation varies significantly depending on the parameters of the explosive load, which depends on the type of emergency explosion. Based on the general picture of destruction, it is possible to determine the type of emergency explosion, for which the parameters of the gas-dynamic flows that accompanied the emergency explosion can be determined by calculation. This makes it possible to reconstruct the scenario of the emergency explosion, and sometimes the scenario of the entire accident.

In the present paper using the example of an analysis of the accident consequences and the performed calculations of the gas-dynamic flows formed during the emergency explosion, the scenario of the emergency situation development is reconstructed, which allows to speak about the causes of the collapse of building structures that occurred as a result of the accident, and about the degree of guilt of the witnesses of the accident.

Materials and methods. A brief description of the calculation methods that makes it possible to calculate the explosive pressure fields formed during the emergency explosion is given. A brief description of the methods developed by the author for calculating gas-dynamic flows accompanying the emergency explosion is given.

Research results. The results of physical modelling of local deflagration explosions in premises, performed in the laboratory of the university of civil engineering, are reviewed and analyzed. An analysis comparing the calculation results with experimental data is carried out. The results of calculation of explosive pressure parameters and gas-dynamic flows accompanying a real emergency situation are presented. The calculation results made it possible to reconstruct with sufficient accuracy the scenario of the accident development accompanied by the explosion.

Conclusions. It is shown that the developed mathematical models quite accurately describe the field of explosive pressure and gas-dynamic flows created by emergency explosions. Calculation of gas-dynamic flows accompa­nying the emergency explosion makes it possible to reconstruct the scenario of its development. The main features and difficulties arising during mathematical modelling and experimental studies of explosive loads formed during emergency explosions are described.

It is shown that for the correct prediction of loads that are realized during emergency explosions, it is necessary to model physical processes clearly and correctly and to consider scenarios of development of an emergency situation that most adequately correspond to the considered object and the surrounding buildings.

The results of calculation of explosive pressure parameters and gas-dynamic flows accompanying a real emergency situation are presented. An example of reconstructing the development scenario of the explosive accident is given.

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