POST PROCESSING METHOD FOR SIMULATED LAGRANGIAN SPRAY FIELD BASED ON MIE SCATTERING THEORY

Abstract

Numerical simulation and experiment are the two main methods in the investigation of spray and atomization. Some crucial parameters of simulation models are supposed to be calibrated using corresponding experimental data. However, direct comparisons between simulation data and experimental results might be confusing when focusing on spray boundaries or penetration, as the light scattering physics during imaging is always likely to be ignored in computational fluid dynamics (CFD) post-processing. In many cases, CFD provides invisible droplets, resulting in variance in the boundary confirming process. Previous studies discussed backlit conditions in Euler-based simulations to identify spray boundaries, but for most commonly used Lagrangian-based simulations, which are often coupled with Mie scattering experiments, this topic remains undiscussed. In Lagrangian-based methods, droplets are treated as discrete particles, where scattering plays a more crucial role. In this study, light intensity analysis based on Mie scattering theory and intensity integration focusing on Lagrangian field has been presented, aiming to adjust simulation data of spray coincides with Mie scattering image as much as possible on the theoretical base. It is found that particle size and in-parcel numbers are related to the scattering intensity of droplet particles. the correlated CFD data using Mie scattering theory are tested to be theoretically similar with Mie scattering imaging results compared with raw simulation data, making the comparison between datasets reasonable, which makes adequate preparations for the calibration of spray models.