Laser Treatment of Surfaces for Pool Boiling Heat Transfer Enhancement

Area of Science:

• Materials Science
• Thermodynamics
• Surface Engineering

Background:

• Laser surface treatment offers a versatile method for modifying material properties.
• Enhancing pool boiling heat transfer is crucial for efficient thermal management in various applications.
• Surface morphology significantly influences heat transfer dynamics.

Purpose of the Study:

• To investigate laser-induced surface modifications for enhanced pool boiling heat transfer.
• To analyze the effect of laser processing parameters on microfin height and surface roughness.
• To evaluate the impact of macro- and micro-scale surface structures on heat transfer performance.

Main Methods:

• Laser beam processing was used to create microfins (grooves) and surface roughness on samples.
• Optical profilometry and microscopy were employed to measure microfin height and surface roughness.
• Pool boiling experiments were conducted with distilled water and ethyl alcohol on modified horizontal surfaces.
• A modified boiling heat transfer model was developed and validated against experimental data.

Main Results:

• Optimal laser parameters (250 ns pulse duration, 200 mm/s scanning velocity) produced the highest microfins and surface roughness.
• Enhanced heat transfer was observed for surfaces with larger microfins and increased roughness, particularly at low superheats.
• Heat flux increased over three times for water and two times for ethanol with 0.4 mm microfins compared to 0.2 mm microfins.
• The developed correlation for laser-processed surfaces showed good agreement with experimental data (within ±100%).

Conclusions:

• Laser surface texturing is an effective technique for significantly improving pool boiling heat transfer.
• The study provides optimal processing parameters for maximizing surface enhancements.
• The developed heat transfer model accurately predicts performance for laser-modified surfaces, aiding in thermal system design.