Date of Award

8-2025

Document Type

Thesis

Degree Name

Master of Engineering (ME)

Department

Mechanical Engineering

Committee Chair/Advisor

Dr. Huijuan Zhao

Committee Member

Dr. Gang Li

Committee Member

Dr. Hai Xiao

Abstract

Microreactors are a type of small-scale chemical reactors for achieving reduced volume, improved product selectivity and higher reaction rate. It allows precise temperature control, which is crucial for sensitive chemical processes. Microreactors can be employed as key components of conducting small-scale reactions with improved reactor configuration and process efficiency. It is important to identify a localized and precise heating mechanism to trigger and control the corresponding chemical reactions.

In fact, microwave heating has gathered significant attention in recent years due to its ability to deliver efficient, rapid, and localized heating, which can accelerate reaction rates and enhances the reaction selectivity. This ability makes microwave heated micro-reactors a promising product for industrial applications with fine control of temperature field, reaction rate, and precise chemical synthesis.

Over the years, multi-physics simulations have been adopted to understand the complexities of microwave heating, optimize the microreactor design, and predict the temperature distributions and reaction rates. However, in most of the established multi-physics models, energy exchange due to chemical reactions have not been considered. Meanwhile, the reactants’ material properties such as permittivity and thermal conductivity varies as the reaction progresses. Such material property variation may directly influence the efficiency of microwave heating and are worth investigating.

To address these shortcomings, an extension to the current multi-physics model is proposed through COMSOL by incorporating energy dynamics during chemical reactions and the variation of material properties as a function of temperature and mass content. The extended model accounts for the heat exchange during the chemical reaction, the temperature sensitive material properties, and the variation of the reactant mass ratio during the reaction progresses. A solid phase reaction of limestone decomposition is adopted for model validation purposes. The roles of energy dynamics, material properties variation, microwave characteristics and microreactor geometry characteristics to the temperature distribution of the microreactor and the efficiency of the microwave heating are investigated.

Even though future systematic studies needs to be conduct and the results need to be validated, this work established a framework for future developments in microreactor design under microwave heating.

Available for download on Monday, August 31, 2026

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