Suppression of hydrogen–oxygen–nitrogen explosions by fine water mist: Part 1. Burning velocity

Suppression of hydrogen–oxygen–nitrogen explosions by fine water mist: Part 2. Mitigation of vented deflagrations

“…There is a strong relationship between the rate of pressure rise during combustion and the burning velocity. Consequently, the effect of water mist density on the development of the overpressure is entirely consistent with its effect on the burning velocity which was reported in part (1) of this paper [1]. The strong effect that a high density of water mist exerts on reducing the rate of pressure rise over a wide range of hydrogen concentration is also apparent from Fig.…”

“…After each test the volume of water was allowed to cool to room temperature before further experiments were carried out. The droplet size distribution of the water mist (by volume rather than number) produced by the water mist units was similar to the size distribution of droplets reported in part 1 of this study [1]. This was close to a mono-disperse mist with around 5e6 mm Sauter mean diameter.…”

“…Since the introduction of water mist into premixed flammable hydrogen atmospheres results in a decrease in the burning velocity (c.f. part one of this study [1]) it would be expected that entrained fine water mist would have a significant mitigating effect on the overpressure even at relatively high equivalence ratios.…”

“…It was also intended that the data obtained in the investigation would be of use in subsequent, separate modelling studies involving specialist explosion software such as FLACS. 1 The results of these studies have recently been reported [5].…”

“…In part 1 of this study [1] to consider the practical viability of using fine water mists to mitigate or suppress hydrogen explosions during nuclear decommissioning operations, it was shown that water mist considerably reduces the burning velocity over a wide range of equivalence ratios (F) for fuelfree oxygen fractions between 0.1 and 0.21. The fuel-free oxygen fraction is defined here as a volume ratio in accor-…”