The Effect of an Alcohol Resistant Aqueous Film Forming Foam (AR-AFFF) on the Evaporation, Boiling, and Collision Dynamics of a Water Droplet on a Heated Solid Surface1
نویسندگان
چکیده
An experimental study is presented for droplets containing an alcohol-resistant aqueous film forming foam (AR-AFFF) impacting and boiling on a heated stainless steel surface. Experiments with solutions of 3% (volume fraction) AR-AFFFldistilled water were compared to ones with distilled water and 3% AR-AFFF/simulated seawater. The latter experiments were motivated by the practice of mixing AR-AFFF with seawater in many naval applications. The impact process was recorded using a high-speed digital camera at loo0 frames per second. For each fluid, the droplet impact Weber number was fixed, and the droplet evaporation lifetime was measured as a function of temperature. Collision dynamics were investigated for each fluid, with the temperature of the stainless steel surface varied from film evaporation to film boiling. It was observed that the addition of 3% AR-AFFF to water reduced the temperature for departure from nucleate boiling and the Leidenfrost temperature dramatically compared to pure water. Droplets were observed to breakup violently for solutions of AR-AFFFlsimulated seawater at film boiling. The results demonstrate that the collision dynamics depend on what type of water is mixed with AR-AFFF. o MOZ msevier seieme (USA)
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