Surface Cooling of a Pool Fire by Aqueous Foams. Issue 5 (4th May 2017)

• Record Type: Journal Article
• Authors: Conroy, Michael W.; Fleming, James W.; Ananth, Ramagopal
• Is Part Of: Combustion science and technology. Volume 189:Issue 5(2017)
• Page Start: 806
• Page End: 840
• Publication Date: 2017-05-04
• Subjects: Firefighting foam -- Fire suppression -- Interfacial heat transfer -- Pool fire; Combustion -- Periodicals; Combustion engineering -- Periodicals; 541.36105
• DOI: 10.1080/00102202.2016.1253565
• Languages: English
• ISSNs: 0010-2202

Abstract

ABSTRACT: We model an idealized case of heat transfer relevant for foams used to suppress pool fires wherein an ambient-temperature firefighting foam is placed uniformly and instantaneously on top of a hot fuel pool with a boiling point slightly lower than that of water. We performed experiments using n -heptane fuel and both commercial fluorinated (AFFF) and non-fluorinated (RF6) foams. The measurements show rapid (<10 s) and significant (25°C) cooling of the fuel close to the foam-fuel interface in good agreement with the model predictions. The model also shows that a 60-µm-thick static, aqueous film formed between the foam and fuel surface has a negligible effect on interfacial cooling. Therefore, in addition to forming a fuel-transport barrier to the fire, the foam layer rapidly cools the surface by heat conduction and suppresses fuel evaporation, which suppresses the pool fire.