Water mist is considered as a potential alternative to halon in fire extinguishing applications. However, penetration is remarkably reduced due to the rapid decay of momentum in the process of water mist movement, which makes it difficult for water mist to reach the flame zone to extinguish the fire. To effectively improve the momentum of the water mist, a novel water mist system namely co-flow jet water mist system was proposed. A configuration in which a co-flow jet was induced to control the motion of water mist. A three-dimensional simulation was performed on the gas–liquid flow in this system. The Realizable k-ε model coupled with the discrete phase model (DPM) was employed for high-speed co-flow jet and laden droplets respectively. Simulations were focused on the interaction of the gas–liquid phase. It was found that the potential core length of the co-flow jet was increased owing to the injection of droplets, but the turbulence intensity and the attenuation of the axial velocity of the co-flow jet were reduced by the broken droplets. In addition, the droplets produced by the atomizer were broken into uniform small ones under the action of co-flow jet, and the spatial distribution of droplets was also changed, more importantly, the momentum of droplets was increased effectively. The droplet size as well as spatial distribution and momentum was related to the gas–liquid mass ratio (GLR). The GLR should be increased as much as possible to enhance the performance of the co-flow jet once the required concentration to extinguish a fire is achieved. This technique is helpful to the popularization and application of a water mist system.

细水雾被认为是灭火应用中哈龙的潜在替代品。但由于细水雾运动过程中动量衰减迅速，穿透力显着降低，使细水雾难以到达火焰区灭火。为有效提高细水雾的动量，提出了一种新型细水雾系统，即协流喷射细水雾系统。一种配置，其中诱导并流射流以控制水雾的运动。对该系统中的气液流动进行了三维模拟。可实现的k - ε结合离散相模型 (DPM) 的模型分别用于高速协流射流和负载液滴。模拟的重点是气-液相的相互作用。结果表明，由于液滴的注入，共流射流的潜在核心长度增加，但湍流强度和共流射流轴向速度的衰减被破碎的液滴降低。此外，雾化器产生的液滴在协流射流的作用下破碎成均匀的小液滴，也改变了液滴的空间分布，更重要的是有效增加了液滴的动量。液滴尺寸以及空间分布和动量与气液质量比（GLR）有关。一旦达到灭火所需的浓度，应尽可能增加 GLR 以提高协流射流的性能。该技术有助于细水雾系统的推广应用。