Publications

@article{Zhao2019,

title = {Lateral Flame Spread over PMMA Under Forced Air Flow},

author = {Kun Zhao and Michael J Gollner and Qiong Liu and Junhui Gong and Lizhong Yang},

url = {https://doi.org/10.1007/s10694-019-00904-x http://link.springer.com/10.1007/s10694-019-00904-x},

doi = {10.1007/s10694-019-00904-x},

issn = {0015-2684},

year  = {2019},

date = {2019-09-01},

journal = {Fire Technology},

publisher = {Springer US},

abstract = {In wildland and other flame spread scenarios a spreading fire front often forms an elliptical shape, incorporating both forward and lateral spread. While lateral flame spread is much slower than forward rates of spread, it still contributes to the growth of the overall fire front. In this work, a small-scale experiment is performed to investigate the mechanisms causing this lateral spread in a simple, small-scale configuration. PMMA strips with thicknesses ranging from 1 mm to 3.1 mm and widths of 5 cm and 10 cm were ignited under forced flow in a laminar wind tunnel. Unlike traditional concurrent or opposed flame spread experiments, flames were allowed to progress from one side of the sample to the other, perpendicular to the wind direction. An infrared camera was used to track the progression of the pyrolysis front by estimating the surface temperature of the PMMA. The flame spread rate, depth of the burning region, thermal diffusion length, and radiant heat flux were determined and analyzed. Based on a theory of heat and mass transfer for a laminar diffusion flame, a thermal heat transfer model was developed for the preheating region to predict the lateral flame spread rate. Results show that the thermal diffusion length decreases with wind velocity, ranging from 4.5 mm to 3 mm. Convection dominates the flame-spread rate, accounting for more than 80% of the total heat flux. The theoretical flame spread rate agrees well with experimental data from all but the thinnest samples tested, overpredicting the lateral flame spread rate for 1 mm thick samples. The resulting model for lateral flame spread under concurrent flow works for forced-flow dominated flame spread over thermally-thin fuels and helps provide physical insight into the problem, aiding in future development of two-dimensional, elliptical fire spread models.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Singh2017,

title = {Steady and transient pyrolysis of a non-charring solid fuel under forced flow},

author = {A V Singh and M J Gollner},

doi = {10.1016/j.proci.2016.07.043},

issn = {15407489},

year  = {2017},

date = {2017-01-01},

journal = {Proceedings of the Combustion Institute},

volume = {36},

number = {2},

abstract = {textcopyright 2016 by The Combustion Institute. Published by Elsevier Inc. In previous work, the Reynolds analogy was used to develop a theoretical expression that allowed for the estimation of local mass burning rates in steady laminar boundary layer diffusion flames established over liquid and solid fuels. This technique was used to elucidate the mechanisms responsible for pyrolysis of both solid and liquid fuels in forced and free convective environments. These previous studies, however, focused on steady results that occur early in the combustion process, before regression of the fuel surface begins to influence results. In this work, a thorough experimental investigation of steady and transient pyrolysis of clear cast Poly Methyl Methacrylate (PMMA) is presented using both local pyrolysis rates and heat feedback to the condensed fuel surface measured at different streamwise locations in a bench-scale wind tunnel. A functional form of the Nusselt number is derived that can be readily used to identify these steady and transient regimes of PMMA burning in the form of local convective heat transfer coefficients. At early times ( textless 150 s), a steady burning regime is identified where heat feedback properties are constant and the gas phase can be assumed to be in a steady state. At later times, a transient burning regime dominated by solid-phase effects occurs. Heat feedback from the flame and hence local mass loss rates measured at later times are transient in nature and do not correspond well with the steady state theoretical solution. Investigation under different forced-flow wind conditions reveals this transient phenomena most likely occurs due to both deformation of the surface of PMMA and solid-phase conduction into the fuel, which eventually influences the gas phase. The results presented will be useful for future modeling of transient solid-phase combustion, especially as it is applied to studies of flame spread.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GOLLNER20132531,

title = {Experimental study of upward flame spread of an inclined fuel surface},

author = {M J Gollner and X Huang and J Cobian and A S Rangwala and F A Williams},

url = {http://www.sciencedirect.com/science/article/pii/S154074891200171X},

doi = {https://doi.org/10.1016/j.proci.2012.06.063},

issn = {1540-7489},

year  = {2013},

date = {2013-01-01},

journal = {Proceedings of the Combustion Institute},

volume = {34},

number = {2},

pages = {2531 - 2538},

keywords = {},

pubstate = {published},

tppubtype = {article}

}