Enhanced absorption of fire induced heat radiation in liquid droplets
2013 (English)In: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 55, p. 182-196Article in journal (Refereed) Published
Abstract [en]
The influence of additives on the interaction between radiation from fires and single water droplets has been investigated in detail. A literature study was performed on available information of radiation spectra from different types of fires. Based on this, four reference spectra were proposed that cover most of the different types of radiation that can be expected from fires. These reference spectra were used to compare the effect of different water additives and droplets sizes. Using Mie-theory it was found that increased atomization, down to a diameter limit of 1-10 μm, gives a better volumetric absorption efficiency. Decreasing the diameter further does not lead to improved volumetric absorption since the Rayleigh (small droplet) limit is reached, where the volumetric absorption is independent of diameter. Different additives were investigated with respect to increased absorption in the droplets. It was found, however, that it is not trivial to find non-flammable and non-toxic additives that give a significant improvement in absorption. Carbonated water was a potential candidate but the increased absorption was limited to a very weak band centered at 2300 cm-1. Since this coincides with the strong CO 2 emission band an effect could be seen when carbonated water interacted with radiation from clean flames. The maximum increase in volumetric absorption for carbonated water was 4%, occurring for a droplet diameter of 10 μm. Other additives gave better effects but they were either combustible (carbon nanopowder) and/or toxic to some degree.
Place, publisher, year, edition, pages
2013. Vol. 55, p. 182-196
Keywords [en]
Absorption, Additive, Droplet, IR-radiation, Mie theory, Spray, Absorption efficiency, Carbon nanopowders, Carbonated waters, Diameter limit, Droplet diameters, Emission bands, Enhanced absorption, Liquid droplets, Radiation spectra, Rayleigh, Reference spectrum, Small droplets, Water additives, Water droplets, Additives, Carbon dioxide, Carbonation, Drops, Fires, Water absorption
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ri:diva-49918DOI: 10.1016/j.firesaf.2012.10.005Scopus ID: 2-s2.0-84870926395OAI: oai:DiVA.org:ri-49918DiVA, id: diva2:1484802
Note
Funding details: Ångpanneföreningens Forskningsstiftelse; Funding text 1: This work was partly sponsored by Ångpanneföreningens Forskningsstiftelse with Ref. No. 10–115 which is gratefully acknowledged. Acknowledgment is given to the staff at SP who has contributed to this project. Special thanks to Raúl Ochoterena for fruitful discussions and for carefully reading and commenting the manuscript, and to Leena Andersson for determining the volume fraction of carbon nanopowder. Prof. Pascal Boulet at Laboratoire d'Energétique et de Mécanique Théorique & Appliquée (LEMTA) at Université Henri Poincaré in Nancy, France, is gratefully acknowledged for providing measurement data of spectral radiance from fires. Dr. Michael Klassen, Combustion Science & Engineering, Inc., and Prof. Jay Gore, Purdue University, are gratefully acknowledged for providing additional information about their pool fire experiments.
2020-10-302020-10-302023-05-25Bibliographically approved