Investigation of temperature fields around embedded cryoprobes

Area of Science:

• Cryogenics
• Heat Transfer
• Medical Device Engineering

Background:

• Cryoprobes are essential tools in various medical and scientific applications.
• Accurate temperature field prediction is crucial for effective cryoprobe operation.
• Existing models may not fully capture the complex thermal dynamics around cryoprobes.

Purpose of the Study:

• To analytically and experimentally investigate the temperature fields surrounding two distinct cryoprobes.
• To compare the accuracy of different analytical methods, including integral and finite element solutions.
• To identify factors contributing to discrepancies between analytical predictions and experimental measurements.

Main Methods:

• Employed a spherically shaped general purpose cryoprobe (liquid nitrogen) and a cylindrical glaucoma cryoprobe (Joule-Thomson effect in CO2).
• Utilized commercial cryostats for probe operation.
• Developed analytical solutions based on the enthalpy method: a 1D integral solution and finite element solutions.
• Conducted experimental measurements to validate analytical models.

Main Results:

• Analytical and experimental temperature field data demonstrated reasonable agreement for both cryoprobes.
• Finite element solutions provided detailed thermal profiles for both probe types.
• The enthalpy method was effectively applied to model the cryoprobes' thermal behavior.

Conclusions:

• The study successfully validated analytical models against experimental data for cryoprobe temperature fields.
• Incomplete specification of cryoprobe surface boundary conditions is identified as a primary source of deviation.
• Findings contribute to improved understanding and design of cryoprobe thermal management systems.