A simplified model for thermal-wave cavity self-consistent measurement of thermal diffusivity

Area of Science:

• Thermodynamics
• Fluid dynamics
• Optical techniques

Background:

• The thermal-wave cavity (TWC) technique is a method for measuring thermal properties.
• Accurate measurements of thermal diffusivity are crucial in various scientific and engineering fields.
• Existing TWC methods often require detailed knowledge of geometrical and thermal parameters, limiting their applicability.

Purpose of the Study:

• To develop a simplified theoretical model for the TWC technique.
• To incorporate thermal radiation effects into the TWC model.
• To enable absolute measurements of thermal diffusivity for gas and liquid samples without prior knowledge of system parameters.

Main Methods:

• Development of a simplified theoretical model for the thermal-wave cavity (TWC) technique.
• Inclusion of thermal radiation effects in the model.
• Utilizing cavity-length scans for measurements.

Main Results:

• The developed TWC model accurately measures thermal diffusivity without needing geometrical or thermal parameters.
• Thermal diffusivity of air was measured as (2.191 ± 0.004) × 10(-5) m(2) s(-1).
• Thermal diffusivity of distilled water was measured as (1.427 ± 0.009) × 10(-7) m(2) s(-1).

Conclusions:

• The simplified TWC model provides a robust method for absolute thermal diffusivity measurements.
• The technique is effective for both gaseous and liquid samples.
• Experimental results show excellent agreement with established literature values, validating the model.