Experimental study on interaction of water mist spray with high-velocity gas jet

Publication date: October 2017
Source:Fire Safety Journal, Volume 93
Author(s): P. Zhu, X.S. Wang, G.C. Li, Y.P. Liu, X.X. Kong, Y.Q. Huang, X.D. Zhao, J.W. Yuan
Water mist spray is considered a potential and effective method for controlling or mitigating the risk of natural gas (NG) leakage. In order to address the lack of understanding of the dynamical behaviours and interacting mechanisms between water mist spray and high-velocity leakage gas jets, a series of small-scale experiments were conducted by means of a 2D particle image velocimetry technique. For safety reasons, nitrogen was tested instead of NG. The results demonstrate that the two-phase flow field could be divided into gas- or spray-dominant flow for different gas-spray momentum ratios. The exponential correlation model based on the effective gas-spray momentum ratio ΦEff could predict the vertical gas-spray interaction interface position more effectively. The gas-spray momentum ratio and relative gas-spray opening angle values are important factors affecting the gas-spray interaction. An effective gas-spray momentum ratio of ΦEff<1 is necessary for practical applications. A counter-rotating vortex pair is formed due to the entrainment effect of the high-velocity gas flow, which may enhance the mitigation efficiency by means of effective gas-droplet mixing. The comparison of Nozzle A with Nozzle B indicates that the water mist spray with larger coverage relative to the gas plume should exhibit superior performance in terms of controlling or mitigation effects.



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