Design of annular-shaped heater for measurement of anisotropic thermal conductivity using 3-ω method

Abstract

The 3-ω method has attracted attention for measuring anisotropic thermal conductivity; however, its implementation for measuring anisotropic thermal conductivity is challenging due to complex design requirements and the necessity of large surface area and multiple AC current sources. To address these limitations, this study aims to develop a simple and practical method for measuring anisotropic thermal conductivity using an annular heater design. As a novel solution, the annular heater enables simultaneous measurement of thermal conductivity in multiple directions using a single AC power source, thereby reducing both spatial and instrumentation requirements. The developed annular heater design was validated using FEM simulations. The results indicate that the proposed methodology, which was derived from the line heater, is applicable when the heater radius is sufficiently large (>500 μm). Consequently, it was confirmed that the thermal conductivity could be measured with a maximum error of 5% for the isotropic thermal conductivity and that of 8% for the anisotropic thermal conductivity when the anisotropic ratio was 2. Thus, this study presents a novel and efficient method for accurately measuring anisotropic thermal conductivity using an annular heater, thereby advancing the characterization of anisotropic materials and supporting the development of miniaturized devices.

Keywords

• Anisotropic thermal conductivity
• 3-ω method
• Annular heater
• Thermal sensing
• Thermal reliability