Mirror image technique for the thermal analysis in cryoablation: Experimental setup and validation.

Area of Science:

• Thermodynamics
• Materials Science
• Cryogenics

Background:

• Understanding freezing front dynamics is crucial for applications involving cryogenics and material processing.
• Characterizing thermal behavior at the interface between a cold probe and a material is essential for predicting freezing phenomena.

Purpose of the Study:

• To investigate and characterize the freezing front propagation in water and agar-gel solutions.
• To assess the utility of monitoring cryodevice temperatures for deriving information about external thermodynamic changes.
• To evaluate the impact of thermal contact resistance on ice formation detection.

Main Methods:

• Experimental setup utilizing Peltier devices for cryogenic effect emulation and a copper cold finger as a cold probe interface.
• Application of the mirror image technique to detect initial ice formation and monitor its propagation.
• Measurement of temperatures at the cryodevice to infer thermodynamic changes and ice penetration.

Main Results:

• Ice penetration exhibited a non-linear relationship with time, proportional to the square root of time for both water and agar.
• Ice drift velocity decreased as penetration depth increased.
• Initial drift velocities were approximately 0.11 mm/s (water) and 0.06 mm/s (agar), reducing to ~0.03 mm/s for both after 2 mm penetration.

Conclusions:

• The mirror image technique effectively detects ice formation and penetration, even with varying thermal contact resistance.
• Cryodevice temperature monitoring provides valuable insights into external thermodynamic changes during freezing.
• The observed non-linear ice penetration and decreasing drift velocity are key characteristics of freezing in water and agar gels.