Quantifying the evolution of flow boiling bubbles by statistical testing and image analysis: toward a general model.

Area of Science:

• Multiphase flow dynamics
• Heat transfer phenomena
• Statistical process analysis

Background:

• Distinguishing multiphase components or tracers can be challenging.
• Understanding flow pattern evolution is crucial for process optimization.
• Direct contact boiling heat transfer involves complex fluid dynamics.

Purpose of the Study:

• To propose a new index, the estimate of the error variance, for quantifying flow pattern evolution.
• To explore the homogeneity of luminance distribution in direct contact boiling heat transfer.
• To establish a general model for bubble swarm flow patterns and heat transfer.

Main Methods:

• Image analysis and linear statistical modeling were employed.
• F-test was used to assess light uniformity.
• Non-linear methods identified light source direction and position.

Main Results:

• The new index's inflection point correlated with mixing time.
• The index was successfully applied to top-blown stirred tank mixing.
• A quantifying model demonstrated the link between bubble swarm flow and heat transfer.

Conclusions:

• The estimate of the error variance is a valuable tool for analyzing complex mixing processes.
• The findings provide insights into direct contact boiling heat transfer.
• The methodology can be adapted for other challenging mixing investigations.