Experimental Study on the Dynamic Process of a Water Drop with Additives Impact Upon Hot Liquid Fuel Surfaces

In order to deepen the knowledge of surface cooling mechanism on liquid pool fire suppression with multi-component water spray/mist, preliminary experimental studies on water drop with or without additives impacting upon hot liquid fuel surfaces, such as alcohol and molten-ghee were conducted. NaCl and AFFF (Aqueous Film-Forming Foam) were considered as additives. Each liquid fuel was heated to simulate the temperature conditions as it burns or boils. The impacting processes were recorded using a high-speed digital camera with 2,000 fps. The results show that the maximum column height of the jet was enlarged and more daughter drops were splashed in the cases with additives comparing to a pure water drop as it impacted upon alcohol surface. In addition, to the cases with NaCl additive and a 493K molten-ghee surface, a tiny vapor explosion occurred at 36ms and a second vapor explosion occurred at 2563ms, while there was no any vapor explosion occurred to the case with AFFF additive.