An Electromagnetic Time-Reversal Imaging Algorithm for Moisture Detection in Polymer Foam in an Industrial Microwave...

Area of Science:

• Electromagnetics and Applied Physics
• Materials Science and Engineering
• Industrial Process Control

Background:

• Industrial heating systems for polymer foam drying require precise control over moisture distribution.
• Existing methods may lack the resolution or adaptability for complex material structures.
• Microwave tomography (MWT) offers a potential non-invasive solution for internal property mapping.

Purpose of the Study:

• To design and develop an X-band MWT module for integration with an industrial heating system (HEPHAISTOS).
• To adapt and apply the decomposition of the time-reversal operator (DORT) algorithm for accurate moisture localization in multilayered polymer foam.
• To validate the efficacy of the developed MWT system and algorithm through numerical simulations and experimental data.

Main Methods:

• Design and development of an X-band MWT module with a fixed antenna array.
• Implementation of the DORT algorithm utilizing a Green's function for multilayered media.
• Application of time-reversal imaging (TRI) for moisture localization, including a single-frequency approach to reduce measurement time.
• Testing with numerical simulations and experimental data from a custom MWT prototype.

Main Results:

• The developed Green's function is applicable to multilayered media with varying contrast and moderately rough surfaces.
• Numerical simulations demonstrated the method's efficacy across different moisture scenarios.
• Experimental validation confirmed the TRI algorithm's capability in accurately estimating moisture locations in polymer foam.

Conclusions:

• The integrated MWT system and DORT-based TRI algorithm show significant promise for advanced control in industrial polymer foam drying.
• The proposed method offers a robust solution for non-invasively mapping internal moisture distribution in complex materials.
• Further development could lead to optimized industrial heating processes and improved product quality.