Transport In Rigid And Deformable Hygroscopic Porous Media During Electromagnetic And Combination Heating
Fundamental physics-based modeling integrated with relevant experimentation provides an effective framework to study a variety of transport processes in porous media. The work includes the development of a multiphase porous media model and magnetic resonance imaging (MRI) experiments to study and optimize two processes: microwave combination heating and microwave pufﬁng. Microwave combination heating involves electromagnetic heating combined with other heating modes. The material heated during the process was modeled as a rigid porous medium with multiple phases and modes of transport. The model included three different phases: solid matrix, water and gas (water vapor and air), and considered pressure driven ﬂow, binary diffusion and phase change. The 3D multiphase porous media model was coupled with electromagnetics and was solved using ﬁnite element method. Microwave pufﬁng refers to signiﬁcant structural changes in the material due to high pressure development caused by phase change during rapid heating. The two-way coupling of multiphase porous media transport and large deformation, which is critical to accurately simulate the microwave pufﬁng process, was implemented. MRI and other experiments were designed to obtain spatial temperature and moisture distributions in the material during the heating process to validate the computational models. The results from computations and MRI experiments were analyzed to provide comprehensive and fundamental understanding and to thereby optimize the processes.
dissertation or thesis