Abstract

Analyzing the heat transfer effectiveness of fire suppression systems at droplet level through experimentation is difficult and costly. To overcome this issue, traditional Eulerian–Lagrangian model has been modified to track droplet histories in association with computational fluid dynamics (CFD) fluid models. This allows a comprehensive description of the flame interaction energy migration process of water droplets. The modified Eulerian–Lagrangian approach is adopted to trace every droplet parcel coupled with the fluid closure. Using the in-house code, the histogram of key parameters (e.g. temperature, velocity, mass, etc.) of droplets on microscopic level during suppression are obtained over time-iterations, then subsequently analyzed by statistical approaches, which made the concept of water utilization rate advocated for the first time. Through combination with other key parameters, this concept can effectively indicate the suppression efficiency at droplet level, and thus provide key insights to the design of water mist or more advanced systems. Among the cases studied, with similar suppression time, it is discovered that the water utilization rate can vary from 10% to 26%, based on different design. Tracing the transient movement and evaporation process of water droplets formulates a new approach to effectively study the heat transfer efficiency of water-based fire suppression systems.

抽象的

通过实验在液滴水平上分析灭火系统的传热效率是困难且昂贵的。为了克服这个问题，对传统的欧拉-拉格朗日模型进行了修改，以与计算流体力学（CFD）流体模型关联来跟踪液滴历史。这可以全面描述水滴的火焰相互作用能量迁移过程。修改后的欧拉-拉格朗日方法被采用来追踪每个液滴包裹以及流体封闭。使用内部代码，在时间迭代过程中获得了在抑制过程中微观水平上的液滴的关键参数（例如温度，速度，质量等）的直方图，然后通过统计方法进行分析，从而形成了水的概念首次倡导利用率。通过与其他关键参数结合，该概念可以有效指示液滴水平的抑制效率，从而为水雾或更先进的系统设计提供关键见识。在研究的案例中，具有相似的抑制时间，但根据不同的设计，发现水的利用率可以在10％到26％之间变化。追踪水滴的瞬态运动和蒸发过程，为有效研究水基灭火系统的传热效率制定了一种新方法。根据不同的设计，发现水的利用率可以在10％到26％之间变化。追踪水滴的瞬态运动和蒸发过程，为有效研究水基灭火系统的传热效率制定了一种新方法。根据不同的设计，发现水的利用率可以在10％到26％之间变化。追踪水滴的瞬态运动和蒸发过程，为有效研究水基灭火系统的传热效率制定了一种新方法。