Study on behavior and control of droplets in high-temperature counter gas

doi:10.16265/j.cnki.issn 1003-3033.2020.11.012

Abstract

Abstract: In order to promote penetration properties of water mist, its motion in high-temperature counter flow was studied. Firstly, a motion and heat transfer model of a single droplet was established which was utilized to analyze effects of counter gas and high temperature on velocity and penetration distance of droplets in detail. Then, control effects of co-flow jet on droplets were evaluated. Finally, a method to design a co-flow jet water mist fire extinguishing system was proposed. The results show that it is difficult to effectively increase penetration distance of small droplets by increasing operating pressure at sprinklers, and moreover, droplets are easily entrapped by counter gas. A co-flow jet can help reduce velocity attenuation and increase penetration distance. Furthermore, utilization efficiency of water mist can be improved by a co-flow jet due to decrease of droplet vaporization in flue gas layer and increase of droplets entering flame zone. Structure and operation parameters of a co-flow jet water mist fire extinguishing system can be basically determined according to the design method.

Key words: high-temperature counter gas, water mist, co-flow jet, operating pressure, penetration distance

CLC Number:

X932

HE Mingli, ZHANG Guang, HU Shaohua, WANG Cheng. Study on behavior and control of droplets in high-temperature counter gas[J]. China Safety Science Journal, 2020, 30(11): 82-87.

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