| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 90 === Porous media exists in many kind of energy systems design and applications, such as geothermal usage, compact heat exchangers, spent nuclear fuel storage, heat pipe design. For higher thermal efficiencies requirement, it is important to determine system temperature as accurate as possible. The present investigation looks into the procedure to evaluate porous media heat removal behavior in energy system such as spent nuclear fuel storage using CFD methods.
First, investigation begins with understanding of the basic definitions and fundamental laws and governing equations in porous media approach. Next, we need to explore and test the porous media modeling in CFD code.
We will focus on the situations of spent nuclear fuel interim storage. There are two different designs for fuel rod orientation in interim storage, vertical and horizontal. In either design, the fine matrix of fuel rods and nature convecting cooling helium gas form a particular region that presents important porous media characteristics. With such special geometrical and physical arrangement and CFD porous model, it is expected that more accurate system temperature distributions will be obtained compared to traditionally “homogenization of fuel and gas” approach.
From our simulated results, we noticed that the temperature of porous model is lower than homogenization model in the spent nuclear fuel interim storage. The larger porosity of the fuel assembly, the better heat transfer capability. The steady state solutions are reached in relatively short transient times in porous model.
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