Please cite doi:10.1016/j.proci.2014.07.066 Proceedings of the combustion institute, 35 (3), 2015, 3673-3680 1 Single-shot, time-resolved planar laser-induced incandescence (TiRe-LII) for soot primary particle sizing in flames Z.W. Sun 1, 2, * , D.H. Gu 1, 2 , G.J. Nathan 1, 2 , Z.T. Alwahabi 2, 3 and B.B. Dally 1, 2 1 School of Mechanical Engineering, The University of Adelaide, Australia 2 Center of Energy Technology, The University of Adelaide, Australia 3 School of Chemical Engineering, The University of Adelaide, Australia Abstract: Two dimensional measurements of the size of soot primary particles, in both laminar and unsteady sooty C 2 H 4 /air flames, have been demonstrated in the present work. This is achieved using single-shot, time- resolved laser-induced incandescent (TiRe-LII) technique. The soot primary size is determined from the ratio of different signals obtained from four sequential images together with a theoretical relationship of the LII temporal decays. A laser fluence of 0.30 J/cm 2 was chosen for its relevance to application in turbulent sooty flames where both laser fluence attenuation and beam steering are significant. Planar measurements are firstly demonstrated in a flat laminar flame and the results are found to be in good agreement with time-resolved single-point-measurements using a photomultiplier tube. A typical uncertainty of ± 9 nm is estimated for the single-shot, planar measurements. Finally, planar measurements in an unsteady sooty flame reveal that the size of soot primary particles is very sensitive to local flame conditions. Keywords: laser-induced incandescence, soot primary particles, size, planar image, single-shot