Size Distribution Measurement of Candleʹʹs Soot Nanoparticles by Using Time Resolved Laser Induced Incandescence

Time resolved laser induced incandescence (LII) technique is used to measure size distribution of soot nanoparticles of candleʹs flame. Pulsed Nd:YAG laser is used to heat nanoparticles to incandescence temperature and the resulting signal is measured. Mass and energy balance equations are numerically solved to calculate temperature of soot particles in low fluence regime. Assuming Plank black body radiation and lognormal size distribution for soot particles, the intensity of LII signals are calculated. Using Levenberg-Marquart nonlinear regression algorithm and numerical and experimental LII signals, mean particle size and distribution width of soot nanoparticles are obtained.