本研究提出以市售之柴油引擎，引入加熱器、冷卻器與再生器，且修改曲柄系統，成為一個太陽能α型史特靈引擎之設計。本論文利用FLUENT軟體進行了該引擎之三維單一對稱通道計算流體力學(Computational Fluid Dynamics，CFD)模擬。模式使用RNG k-ε 紊流模式，活塞以附加函數進行動態邊界設定，汽缸採動態網格，再生器則使用能量非平衡模式，即篩網與流體具不同溫度。 針對本研究提出之基本個案以及最佳設計個案，本論文呈現了引擎內部特性之週期變化模擬結果，最佳設計個案之冷卻器帶走較低熱量，引擎以及再生器效率也較佳。利本研究並利用計算流體力學模擬結果，建立了史特靈引擎加熱器、冷卻器與再生器之摩擦因子(friction factor)與納賽數(Nusselt number)關聯式，其回歸相關係數R2皆可達90%以上。這些關聯式是史特靈引擎設計之重要工具。 In a solar desalination project, an alpha type solar Stirling engine is developed from a commercial diesel engine by adding heater, cooler and regenerator as well as modifying crankshaft system. In this thesis, the 3-D Computational Fluid Dynamic (CFD) simulation of a single axi-symmetric channel of the engine is presented. The FLUENT software and the RNG k-ε turbulence model are employed for the simulation. Special treatments are adopted for the simulation, including the piston is defined as a dynamic boundary, the cylinder spaces use dynamic mesh and non-equilibrium model is used for the regenerator, where the screen solid and fluid are different in temperature. The simulation results reveal that compared to the base design, the optimal design releases less heat from the cooler and has higher efficiencies of engine and regenerator. The CFD simulation results are utilized to develop correlations of friction factor and heat transfer coefficient for each heat exchanger. These correlations are valuable design tools for Stirling engines.
