Abstract
Fire whirls are standing vortex structures that often form in forest fires. Here, we report an experimental study of a laboratory burner fire whirl generated using the fixed-frame method, with a particular focus on the velocity field associated with the whirl. Even under controlled laboratory conditions, the velocity field is not easily characterized. Fire whirls are inherently unsteady, which tends to smear time averages, and precession of the core can cause additional spatial smearing. In our experiments, we use particle image velocimetry to overcome these challenges, and report instantaneous snapshots of the flow field inside and outside the core, as well as ensemble-averaged results that take into account the unsteady motion of the whirl axis. We find the ensemble-averaged velocity field closely resembles a Burgers vortex for the upper 60% of the whirl. Near the base region (within one burner diameter of the base), a double ring structure is seen which is likely made up of two vortex rings. Also, entrainment into the whirl appears to be dominated by the radial flow in the base region.
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References
Adrian RJ, Westerweel J (2011) Particle image velocimetry, vol 30. Cambridge aerospace. Cambridge University Press, Cambridge
Akhmetov DG, Gavrilov NV, Nikulin VV (2007) Flow structure in a fire tornado-like vortex. Dokl Phys 52(11):592–595
Bailey SCC, Tavoularis S (2008) Measurements of the velocity field of a wing-tip vortex, wandering in grid turbulence. J Fluid Mech 601:281–315
Chuah K, Kuwana K, Saito K (2009) Modeling a fire whirl generated over a 5-cm-diameter methanol pool fire. Combust Flame 156(9):1828–1833
Graftieaux L, Michard M, Grosjean N (2001) Combining PIV, POD and vortex identification algorithms for the study of unsteady turbulent swirling flows. Meas Sci Technol 12:1422–1429
Hartl KA (2016) Experimental investigations of laboratory fire whirls. Ph.D. thesis, Princeton University, Princeton, NJ, USA
Hartl KA, Smits AJ (2016) Scaling of a small scale burner fire whirl. Combust Flame 163:202–208
Hassan MI, Kuwana K, Saito K, Wang F (2005) Flow structure of a fixed-frame type fire whirl. Fire Saf Sci Proc Eighth Int Symp 8:951–962
Hayashi Y, Kuwana K, Dobashi R (2011) Influence of vortex structure on fire whirl behavior. Fire Saf Sci Proc 10:671–680
Klimenko AY, Williams FA (2013) On the flame length in firewhirls with strong vorticity. Combust Flame 160:335–339
Kuwana K, Morishita S, Dobashi R, Chuah KH, Saito K (2011) The burning rate’s effect on the flame length of weak fire whirls. Proc Combust Inst 33:2425–2432
Lei J, Liu N, Zhang L, Chen H, Shu L, Chen P, Deng Z, Zhu J, Satoh K, de Ris JL (2011) Experimental research on combustion dynamics of medium-scale fire whirl. Proc Combust Inst 33:2407–2415
NIST (2014) Thermodata engine v6.0. https://www.nist.gov/mml/acmd/trc/thermodata-engine
Neal DR, Sciacchitano A, Smith BL, Scarano F (2015) Collaborative framework for PIV uncertainty quantification: the experimental database. Meas Sci Technol 26:1–17
Prasad AK, Adrian RJ, Landreth CC, Offutt PW (1992) Effect of resolution on the speed and accuracy of particle image velocimetry interrogation. Exp Fluids 13:105–116
Tohidi A, Gollner MJ, Xiao H (2018) Fire whirls. Annu Rev Fluid Mech 50:187–213
Wang P, Liu N, Zhang L, Bai Y, Satoh K (2015) Fire whirl experimental facility with no enclosure of solid walls: design and validation. Fire Technol 51:951–969
Wang P, Liu N, Hartl K, Smits AJ (2016) Measurement of the flow field of fire whirl. Fire Technol 52(1):263–272
Weissler GL, Carlson RW (1980) Vacuum physics and technology, vol 14. Methods of experimental physics. Academic Press, Cambridge
Wieneke B (2015) PIV uncertainty quantification from correlation statistics. Meas Sci Technol 26:1–10
Xue Z, Charonko JJ, Vlachos PP (2015) Particle image pattern mutual information and uncertainty estimation for particle image velocimetry. Meas Sci Technol 26:1–14
Acknowledgements
The assistance of Mr. Timothy Bennett in helping with the design and construction of the experimental apparatus used in this study is greatly appreciated. Part of this work was supported by Princeton University’s Andlinger Center for Energy and the Environment.
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Hartl, K.A., Smits, A.J. Stereo PIV measurements in fire whirls. Exp Fluids 60, 17 (2019). https://doi.org/10.1007/s00348-018-2661-6
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DOI: https://doi.org/10.1007/s00348-018-2661-6