Chemically Enhanced Water Mists for Fire Suppression
Abstract
The fire suppression effectiveness of aqueous solutions is studied using an opposed-jet diffusion flame burner with a droplet/particle seeding system designed to minimize loading uncertainties. An aqueous solution is sprayed into the oxidant stream in a heated chamber. The liquid evaporates, leaving residual solid particles in the case of solid solutes. SEM imaging of residual particles indicates a mean diameter of approximately 0.5 microns. Extinction measurements are presented for a variety of phosphorus-containing compounds as well as NaCl and sodium phosphate, with different loadings, solution concentrations, and oxidants. Flame calculations with two detailed phosphorus combustion mechanisms are also performed for some cases, neglecting all particle physical effects. Experiments indicated that all additives containing phosphorus had roughly the same effect on flame suppression, per mole phosphorus added. Additives producing residual particles were somewhat more effective than those that evaporated completely, suggesting a moderate enhancement of fire suppression due to particle physical effects. However, this result is also consistent with chemical differences between additives. Synergy between water and chemical suppressants was predicted computationally but not observed experimentally. Computations underpredicted flame suppression effectiveness by at least a factor of four.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2002
- Accession Number
- ADA412149
Entities
People
- Elizabeth M. Fisher
- Tina M. Jayaweera
Organizations
- Sibley School of Mechanical and Aerospace Engineering