Annotation:
Experimental studies of processes of liquid hydrogen spill and evaporation and the generation of explosive and fire-hazardous hydrogen-air mixtures in a partially confined space with varying degrees of confinement (varying degrees of leakage of openings) on a stand of 96 m3 volume have been conducted, which involved the ignition of mixtures with delayed and non-delayed inflammation and the measurement of overpressure of explosion; the impact of water screen on these processes have been studied as well.
The experiments with duty torches feature rapid combustion of the mixture when the boundary of the generating explosive cloud approaches the area of installed burners, and the volume of the faintly glowing flame of the burning-out mixture rises to a significant height. For all the experiments, the overpressure in the shock wave generated by the flame was approximately the same, equal to 0.8–1.2 kPa.
For experiments with delayed ignition, the generation and development of a visible hydrogen-air mixture cloud and its rapid combustion at the activation of burner flares were registered; the visible flame velocities reached 3,050 m/s. At the same time, the delayed ignition within the range of 1–3.2 s did not cause a significant increase of overpressure in the shock wave.
Therefore, the specifics of the mixture combustion process in case of liquid hydrogen spills in a confined space are mainly determined by the conditions of mixture generation that significantly differ from the conditions of the generation of hydrogen-air mixture in free space.
When hydrogen-air mixtures are exposed to a water screen after the ignition in a confined space, as well as in the air atmosphere, the processes of mixture combustion are activated due to initial combustible mixture flame turbulence. The turbulence of the initial combustible mixture flame is conducted on droplets acting as a periodic volumetric obstacle on the route of the flame front intensifying the flame. At the same time, water screens, with preemptive action, reduce the pressure in the shock wave by the time of the hydrogen spill.
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