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Title: EXTINCTION DROPLET SIZING MEASUREMENTS IN DIESEL RELEVANT SPRAYS

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OSTI ID:1785737

A new diagnostic for the quantification of Sauter Mean Diameter (SMD) in high-pressure fuel sprays has been recently developed using combined optical and x-ray measurements at the Georgia Institute of Technology and Argonne National Laboratory, respectively. This diagnostic utilizes liquid scattering extinction measurements from diffuse back-illumination (DBI) imaging, conducted at Georgia Tech, and liquid absorption measurements from x-ray radiography, conducted at Argonne’s Advanced Photon Source. The new diagnostic, entitled the Scattering Absorption Measurement Ratio (SAMR), quantifies two-dimensional distributions of path-integrated SMD, enabling construction of the spatial history of drop size development within practical fuel sprays. This technique offers unique benefits over conventional drop-sizing methods in that it can be more robust in optically dense regions of the spray, while also providing high spatial resolution of the corresponding droplet field. The spatially-resolved SMD measurements that result from the SAMR diagnostic will be especially valuable to the engine modeling community for the quantitative validation of spray submodels in engine CFD codes. The methodology for quantification of SMD distributions using the SAMR technique has been previously introduced. This thesis aims to extend the initial development of the SAMR technique by presenting in detail: the experimental methodologies used in the SAMR technique, including the development of an ideal DBI setup for this technique; the data processing methodologies developed by the author; two-dimensional Sauter Mean Diameter measurements within diesel sprays for various experimental conditions; a summary of the various sources of measurement uncertainty; an assessment for how the sources of uncertainty affect the quantified SMD; and paths to improve the technique moving forward. The SMD results show that for low ambient density conditions droplets decrease in size as radial and axial position increases. For high ambient density conditions, however, the droplets show a stable size near the spray centerline and steadily increase in size as distance from the centerline increases. Additionally, this work provides 2-D droplet sizing maps which are particularly useful for model validation.

Research Organization:
Georgia Tech Research Corporation (Georgia Institute of Technology)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office
Contributing Organization:
Argonne National Laboratory
DOE Contract Number:
EE0007333
OSTI ID:
1785737
Country of Publication:
United States
Language:
English