Water mist based systems have emerged as potentially lucrative alternatives to Halon-based fire suppression systems and have been extensively studied in the literature. In the present work, experimental investigations are carried out on the performance of the water mist nozzles in extinguishing pool fires of diameter 0.1 m, 0.2 m, and 0.3 m with diesel and heptane as fuels. The growth of the fire is studied for these fires by measuring the transient mass burning rates. Water mist is generated by passing plain water at room temperature through single-head solid-cone pressure-swirl nozzles with X-type swirl-inserts. The nozzle is directed vertically downwards and operated at various heights (0.75 m to 2 m) from the fuel surface with the injection pressure ranging from 6 bar to 10 bar. The extinction performances of four nozzles with orifice diameters of 1.2 mm, 1.65 mm, 1.9 mm, and 2.45 mm are investigated through videography. A comparison of the extinction performances by all the nozzles is presented and the optimal nozzle based on the consumption of water is reported for a given fire. An empirical correlation for the extinction time is reported in both the dimensional and non-dimensional form. Observed interactions of the spray with fuel surface are reported depicting probable undesired phenomena in the application of the water-mist system with top injection.

基于水雾的系统已经成为基于哈龙的灭火系统潜在的有利可图的替代品，并且已在文献中进行了广泛的研究。在目前的工作中，对以柴油和庚烷为燃料的直径为0.1 m，0.2 m和0.3 m的水池扑灭水雾喷嘴的性能进行了实验研究。通过测量瞬态质量燃烧速率，研究了这些火灾的火势增长。室温下的普通水通过带有X型旋流插入物的单头实心圆锥压力旋流喷嘴时会产生水雾。喷嘴垂直向下指向，并在距燃油表面不同高度（0.75 m至2 m）的范围内工作，喷射压力范围为6 bar至10 bar。通过摄像研究了四个孔口直径分别为1.2mm，1.65mm，1.9mm和2.45mm的喷嘴的消光性能。对所有喷嘴的消光性能进行了比较，并针对给定的火灾报告了基于水消耗的最佳喷嘴。消光时间的经验相关性以维度和非维度形式报告。据报道，喷雾与燃料表面的相互作用描述了在顶部喷射水雾系统的应用中可能出现的不良现象。消光时间的经验相关性以维度和非维度形式报告。据报道，喷雾与燃料表面的相互作用描述了在顶部喷射水雾系统的应用中可能出现的不良现象。消光时间的经验相关性以维度和非维度形式报告。据报道，喷雾与燃料表面的相互作用描述了在顶部喷射水雾系统的应用中可能出现的不良现象。