Laser-induced incandescence calibration via gravimetric sampling

Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

“…The proportionality constant C cal , which is given by the optical system, may be obtained by calibration measurements of flames with a known soot volume fraction or by a single soot concentration value acquired by an independent technique, often based upon extinction measurements [49,50] or gravimetric analysis [51]. A self-calibrating LII procedure has also been described by Snelling et al [52] where absolute light intensity is measured and no independent calibration is required.…”

2D soot volume fraction imaging in an ethylene diffusion flame by two-color laser-induced incandescence (2C-LII) technique and comparison with results from other optical diagnostics

“…LII signals are highly nonlinear with laser fluence [6,[13][14][15][16][17][18] as a result of several competing factors such as the delay and width of the detection gate, the spectral bandpass, soot vaporization, and morphological changes of soot particles at high laser fluence [19][20][21][22][23][24]. Actual measurements of soot volume fraction are in general obtained through a calibration procedure performed with the aid of a ''standard'' flame, where soot distribution is known by other techniques [12,13,[25][26][27][28].…”

Soot Measurements in a Simulated Engine Exhaust Using Laser-Induced Incandescence

“…21 ;26;27 Volume fraction calibrations of the LII signal have employed extinction measurements 11 -18 or sampling methods. 10 The versatility and the inherent challenges of LII are evidenced in the various means of generating and detecting the LII signal. Various approaches have attempted to minimize the interference from scattering (including Mie and Raman), the atomic or molecular emissions (PAH, C 2 ) typical of high-intensityvisible excitation, and ame luminance(more noticeableat longer wavelengths).…”