Quantitative, three-dimensional diagnostics of multiphase drop fragmentation via digital in-line holography

Area of Science:

• Fluid Dynamics
• Optical Metrology
• Multiphase Flow Characterization

Background:

• Characterizing multiphase fragmentation is crucial for understanding complex fluid dynamics.
• Digital in-line holography (DIH) offers potential for high-resolution, quantitative analysis of dynamic processes.

Purpose of the Study:

• To demonstrate the quantitative application of DIH for characterizing multiphase droplet fragmentation.
• To validate the accuracy of DIH combined with a hybrid analysis method for droplet breakup studies.

Main Methods:

• Sequential holograms of ethanol droplet breakup in an aerodynamic flow field were recorded using DIH.
• A hybrid method was employed to extract 3D droplet location, size, and rim morphology.
• Particle matching between sequential frames determined droplet velocity.

Main Results:

• DIH successfully captured various stages of droplet breakup, including deformation, bag growth, and rim breakup.
• The hybrid method accurately determined the 3D characteristics of secondary droplets and rim morphology.
• Velocity measurements derived from DIH showed excellent agreement with phase Doppler anemometry (PDA) data.

Conclusions:

• DIH provides a powerful quantitative tool for multiphase fragmentation analysis.
• The hybrid analysis method enhances the accuracy and detail of DIH measurements for droplet dynamics.
• DIH is a validated and accurate alternative to traditional methods like PDA for such applications.