Numerical analysis of ballistic imaging for revealing liquid breakup in dense sprays
Journal article, 2010

This work demonstrates the capacity of a ballistic imaging instrument to suppress diffuse photons and improve image contrast, making it possible to view fluid structure in a spray where a fog of droplets occludes the near field. Analysis of the system is performed by means of a numerical system model. The model simulates light propagation and scattering in the measurement volume using a Monte Carlo based solution to the radiative transfer equation, and includes treatment of the full system optics using a custom ray-tracing code. Simulation results for the validation case where source light illuminates a test chart inside a turbid (optical depth OD = 14) solution of monodisperse polystyrene spheres (d = 0.7 mu m) show good agreement with experimental images. The model is further applied by replacing the solution of polystyrene spheres with a spraylike scattering medium. Here, we investigate the temporal characteristics of an ultrashort (100 fs) laser signal crossing a volume containing a polydisperse distribution of fuel droplets with a representative Sauter mean diameter, D-32 = 23 mu m. These quantitative predictions allow the effectiveness of both the spatial and temporal filtering of the ballistic imaging instrument to be estimated. Results from the model demonstrate that the spatial filtering and time gating effects of the ballistic imaging system significantly improve image contrast, revealing information that is not available with conventional imaging techniques.

system model



mie scattering

laser-light scattering


monte carlo


ballistic imaging


David Sedarsky

Chalmers, Applied Mechanics, Combustion and Propulsion Systems

Edouard Berocal

Lund University

Mark Linne

Chalmers, Applied Mechanics, Combustion and Propulsion Systems

Atomization and Sprays

1044-5110 (ISSN)

Vol. 20 5 407-413

Subject Categories

Mechanical Engineering



More information

Latest update

3/2/2022 6