Laser-induced incandescence calibration in a three-dimensional laminar diffusion flame

A non-buoyant laminar diffusion flame has been studied using laser-induced incandescence (LII) and light extinction measurements. The present flame is established within a laminar boundary layer, producing a complex three-dimensional flow field. This produces a three-dimensional soot concentration field. LII can provide spatially resolved three-dimensional concentration measurements of the soot field, nevertheless it requires calibration. Calibration needs to be conducted under identical conditions to the actual measurements, given the complex interaction between the flow field and soot production. This study reports a calibration procedure that allows the determination of a calibration constant correlating LII signal to soot volume fraction. The potential sources of error are identified and quantified.