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Numerical analysis of ballistic imaging for revealing liquid breakup in dense sprays

Sedarsky, David LU ; Berrocal, Edouard LU and Linne, Mark (2010) In Atomization and Sprays 20(5). p.407-413
Abstract
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
fuel, time-gating, mie scattering, ballistic imaging, monte carlo, spray, system model
in
Atomization and Sprays
volume
20
issue
5
pages
407 - 413
publisher
Begell House
external identifiers
  • wos:000282533100003
  • scopus:78650107220
ISSN
1936-2684
DOI
10.1615/AtomizSpr.v20.i5.30
language
English
LU publication?
yes
id
128be12c-01ea-4635-9829-bbdd6ab4da40 (old id 1728152)
date added to LUP
2010-11-23 09:07:34
date last changed
2018-05-29 10:34:57
@article{128be12c-01ea-4635-9829-bbdd6ab4da40,
  abstract     = {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.},
  author       = {Sedarsky, David and Berrocal, Edouard and Linne, Mark},
  issn         = {1936-2684},
  keyword      = {fuel,time-gating,mie scattering,ballistic imaging,monte carlo,spray,system model},
  language     = {eng},
  number       = {5},
  pages        = {407--413},
  publisher    = {Begell House},
  series       = {Atomization and Sprays},
  title        = {Numerical analysis of ballistic imaging for revealing liquid breakup in dense sprays},
  url          = {http://dx.doi.org/10.1615/AtomizSpr.v20.i5.30},
  volume       = {20},
  year         = {2010},
}