Режимы взрывного горения при аварийных взрывах газовых облаков в открытом пространстве

Abstract

Emergency explosions of steam clouds in the open space occur in the deflagration combustion mode. Destructive force of the explosive waves is mainly determined by the rate of combustion in the steam cloud. Therefore, the issue of explosive combustion rate is the key one for predicting explosion parameters. To form the waves of destructive force, it is required that the combustion rate of the substance in the cloud increase by 30 or more times compared to laminar. The main and generally recognized mechanism of combustion intensification is turbulization of the process as a result of interaction of the gas flow field with various obstacles located in the area of the exploding cloud. In the work, the analysis focuses on the combustion processes in the obstacles with continuously changing blocking of space. Under such conditions, the combustion is not structured, it smoothly changes its characteristics, and not jerks at the locations of blocking barriers. That is, explosive combustion can be considered as a classic turbulent combustion of a homogeneous mixed mixture. The work gives preference to the analysis of works, in which the turbulent combustion rate is presented as allowing a change in the scale of turbulence. The results of these works are presented in the form of functions ff(U¢/Sl, l/d) of the ratio of the pulsation component of turbulence to the laminar combustion rate, and the ratio of the integral scale of turbulence to the thickness of the laminar flame. The work gives a comparison of the turbulent combustion velocity depending on the U¢/SL ratio for three values l/d = 100, 1000, 10 000. On the basis of the turbulent combustion modes diagram, the zones of applicability of various methods for determining the turbulent combustion rate are shown. The paper expresses preference for the Peters theory as the most universal and giving a realistic value of the turbulent combustion rate at l/d >> 1.