Core-shell dry water (DW) has attracted significant attention as a promising candidate for future fire extinguishing agents, owing to its high water content, powdery structure and ease of handling. However, the lack of detailed information regarding the characteristics of DW has considerably hindered efforts to improve its fire extinguishing performance. This study is the first attempt to elucidate the origin of the effects of particle size of DW on fire extinguishment. Pristine DW was fractionated into three different particle sizes via careful sieving. Through systematic analyses, it could be determined that smaller DW could be vaporized at lower temperatures, thereby facilitating good cooling and smoldering of flames. However, small DW cannot sufficiently penetrate flames, which makes it difficult to reach the burning surface. However, medium-sized DW exhibited a balance in its cooling, smoldering, and penetration effects. Thus, it achieved better performance in fire extinguishment when compared to small- and large-sized DWs. It was also demonstrated that the fire extinguishing capability of medium-sized DW can be significantly enhanced by adding NaHCO3 in the water core of the DW.

中文翻译：

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阐明粒径对核壳干水灭火性能的影响

核壳干水（DW）由于其含水量高、粉状结构和易于处理，作为未来灭火剂的有希望的候选物而引起了极大的关注。然而，由于缺乏关于 DW 特性的详细信息，大大阻碍了提高其灭火性能的努力。这项研究是首次尝试阐明 DW 粒径对灭火影响的起源。通过仔细筛分，原始 DW 被分成三种不同的粒径。通过系统分析，可以确定较小的 DW 可以在较低的温度下蒸发，从而促进火焰的良好冷却和阴燃。但是，小的DW不能充分穿透火焰，难以到达燃烧面。然而，中型 DW 在其冷却、阴燃和穿透效果方面表现出平衡。因此，与小型和大型 DW 相比，它在灭火方面取得了更好的性能。研究还表明，在中型水管的水芯中加入碳酸氢钠可以显着增强中型水管的灭火能力。