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Challenges in determining critical mass flux for ignition

Lundström, Frida Vermina LU and Van Hees, Patrick LU (2015) 14th International Conference and Exhibition on Fire and Materials 2015 In Fire and Materials 2015 - 14th International Conference and Exhibition, Proceedings p.198-209
Abstract

Traditionally in fire modelling, a solid fuel has been assumed to ignite when the solids surface reaches a specific temperature or when the heat flux upon the solid reaches a critical level. Although these approaches of determining ignition for the condensed phase are practical, ignoring the gas phase conditions may lead to incorrect assumptions regarding material safety. A more 'physical' explanation for piloted ignition cases may be that ignition occurs when the fuel-air-mixture around the location of a pilot has reached the lower flammability limit. In this study, challenges of retrieving a critical mass flux for piloted ignition is theoretically evaluated. Then a simple model is presented, by which the critical mass flux (analogous... (More)

Traditionally in fire modelling, a solid fuel has been assumed to ignite when the solids surface reaches a specific temperature or when the heat flux upon the solid reaches a critical level. Although these approaches of determining ignition for the condensed phase are practical, ignoring the gas phase conditions may lead to incorrect assumptions regarding material safety. A more 'physical' explanation for piloted ignition cases may be that ignition occurs when the fuel-air-mixture around the location of a pilot has reached the lower flammability limit. In this study, challenges of retrieving a critical mass flux for piloted ignition is theoretically evaluated. Then a simple model is presented, by which the critical mass flux (analogous to the piloted fire point) of a solid fuel's effluents may be obtained. Finally, the model is validated against literature data. Initial results indicate that the model predicts ignition reasonably well, however further validation needs to be done, both when it comes to predicting ignition for different types of materials and for other environments.

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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
Fire and Materials 2015 - 14th International Conference and Exhibition, Proceedings
pages
198 - 209
publisher
Interscience Communications Ltd
conference name
14th International Conference and Exhibition on Fire and Materials 2015
external identifiers
  • scopus:84983134862
language
English
LU publication?
yes
id
aa519c39-782c-4104-a8df-c5ef7ea96e8b
date added to LUP
2016-11-05 14:02:13
date last changed
2017-01-01 08:38:42
@inproceedings{aa519c39-782c-4104-a8df-c5ef7ea96e8b,
  abstract     = {<p>Traditionally in fire modelling, a solid fuel has been assumed to ignite when the solids surface reaches a specific temperature or when the heat flux upon the solid reaches a critical level. Although these approaches of determining ignition for the condensed phase are practical, ignoring the gas phase conditions may lead to incorrect assumptions regarding material safety. A more 'physical' explanation for piloted ignition cases may be that ignition occurs when the fuel-air-mixture around the location of a pilot has reached the lower flammability limit. In this study, challenges of retrieving a critical mass flux for piloted ignition is theoretically evaluated. Then a simple model is presented, by which the critical mass flux (analogous to the piloted fire point) of a solid fuel's effluents may be obtained. Finally, the model is validated against literature data. Initial results indicate that the model predicts ignition reasonably well, however further validation needs to be done, both when it comes to predicting ignition for different types of materials and for other environments.</p>},
  author       = {Lundström, Frida Vermina and Van Hees, Patrick},
  booktitle    = {Fire and Materials 2015 - 14th International Conference and Exhibition, Proceedings},
  language     = {eng},
  pages        = {198--209},
  publisher    = {Interscience Communications Ltd},
  title        = {Challenges in determining critical mass flux for ignition},
  year         = {2015},
}