| Summary: | 碩士 === 中華大學 === 機械與航太工程研究所 === 95 === Stability of thermal convection in a fluid-saturated porous medium was analyzed by using a thermal non-equilibrium model to take account of the interphase heat transfer between the fluid and the solid. The study is based on the five dimensional nonlinear dynamical system deduced by applying the truncated Galerkin expansion to the momentum and heat transfer equations. The effects of the porosity-modified conductivity ratio λ , interphase heat transfer H, and the ratio of diffusivity α , on the onset of convection and the first transition of the convection in a porous medium were analyzed and discussed. The stability analysis revealed that the interphase heat transfer H tends to retard the onset of thermal convection. However, the critical Darcy-Rayleigh number of onset of convection decreases with the porosity-modified conductivity ratio, λ . Even though the onset of convection is independent of α , it is shown the first transition of convection is a strong function of α .
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