Effect of Obstructed Space on the Parameters of Shock Waves from the Deflagration of Hydrogen–Air Clouds

This article considers the generation of pressure waves during the combustion of hydrogen–air clouds in various modes. The problem of the combustion of spherical clouds, in which the inner spherical volume burns with an apparent velocity of 240 m/s, and the remaining outer layer with an apparent velocity of 100 m/s, is considered. Also, for comparison, two limiting cases are considered: the combustion of the entire cloud with constant velocities of 100 and 240 m/s. The problem is solved numerically in a one-dimensional formulation, with the combustion front clearly identified. As a result, using precise numerical simulation, it is shown that the deflagration of secondary volumes of hydrogen–air mixtures in an open space at a slow speed (up to 100 m/s) does not lead to an increase in pressure in the waves generated earlier during the deflagration of the primary volume at a fast speed corresponding to deflagration in an obstructed space. Such a situation is observed for the inner region of various sizes (the portion of the cloud that burns at a high rate).