Simulating the Optical Properties of Soot Using a Stochastic Soot Model

KL extinction measurements are an attractive soot measurement method common in the literature concerning soot-producing sprays because of their nonintrusiveness and 2D or 3D results. Unfortunately, these measurements often rely on bold assumptions of uniform and monodisperse spherical soot particles. In this work, a Spray A case is simulated using a highly detailed 3D stochastic soot model capable of predicting soot particle morphology. The measured and simulated soot volume fraction are compared, and although the simulated volume fraction magnitudes are approximately correct, the simulated volume fraction lacks a core of high volume fraction that the measured data shows. Optical models based on simulated particle size and shape are applied to the simulated data to find the local optical thickness. The simulated optical thickness aligns with the measurement-based volume fraction more closely than the simulated volume fraction indicating KL extinction measurements are not simply related to soot volume fraction.