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ISSN Печать: 1044-5110
ISSN Онлайн: 1936-2684
Indexed in
UTILIZATION OF FINE WATER SPRAYS IN EXPLOSION MITIGATION: COLD TRIAL
Краткое описание
For the past 50 years, there has been a great deal of interest in using water-based explosion suppression systems to mitigate the impact of thermal explosions and their consequential overpressures. Previous researches focused on the suppression and mitigation with sprays containing droplets 200 μm ≤ D32 ≤ 1000 μm. The present study concerns the mitigation of slow-moving deflagrations with speeds of less than or equal to 30 m/s. Consequently, the droplets within the spray must be small enough to extract heat in the short finite moments that the flame and droplets interact at about 0.03 ms for a 1 mm thick flame front. Previous theoretical studies suggested that droplets in the order of 10 to 20 μm would be small enough to mitigate combustion without relying on further droplet break up, although experimental trials were not performed to validate these data. This investigation, however, presents a qualitative and quantitative analysis of using spill return atomizer (SRA) to provide fine water spray ranging from 17 μm ≤ D32 ≤ 29 μm without relying on further breakup. The spray cone angle was increased from 34.7° to 49.2° and the exit orifice flow rate was raised from 0.295 to 1.36 l/min. Increasing the flow rate provided the required range of droplets with liquid volume flux of 0.011 to 0.047 cm3/s/cm2 and mean droplet velocity of 0 to 21.4 m/s. Hence the resulting characteristics are required to mitigate a propagating combustion wave.
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