Dynamic Differential Image Circle Diameter Measurement Precision Assessment: Application to Burning Droplets

Area of Science:

• Combustion science
• Image analysis
• Fluid dynamics

Background:

• Precise measurement of dynamic changes in fuel droplet diameter is crucial for combustion analysis.
• Existing methods struggle with image distortions, defects, and occlusions, particularly from soot.
• The FLEX-2 dataset provides images of fuel droplets undergoing combustion in zero gravity.

Purpose of the Study:

• To develop an automated system for dynamic measurement precision assessment of fuel droplet diameter.
• To quantify measurement precision based on image quality, accounting for occlusions.
• To provide reliable diameter measurements with associated precision for scientific analysis.

Main Methods:

• An automated system using image gradient-based, least-squares boundary point fitting to circle/ellipse models was designed.
• Synthetic image simulations modeling soot behavior were used to develop a precision assessment model.
• The model correlates image quality measures with measurement precision for individual diameter measurements.

Main Results:

• The automated system achieved a 98% success rate for measurable runs.
• A measurement precision of ±0.2 pixels was achieved for the FLEX-2 dataset in cases of limited occlusion.
• The developed model successfully assesses measurement precision based on image quality.

Conclusions:

• The automated system provides accurate fuel droplet diameter measurements with reliable precision assessments.
• The precision assessment model effectively handles challenges posed by soot occlusion.
• This work enables improved scientific analysis of combustion processes using dynamic droplet measurements.