本論文提出一個以柴油引擎為基礎的alpha型空氣史特靈引擎之基本設計，引擎之熱源來自太陽能集光碟之輻射熱，冷端則使用冷卻水移除熱量，引擎內部設計使用具鰭片之平板構成通道的加熱器、由平板構成通道的冷卻器、以及由篩網與篩網間通道構成的再生器。本研究建立了引擎之三階模式，並與滑動結構曲柄的動力模式連結。引擎內部模式針對加熱器、再生器、冷卻器與冷、熱汽缸求解各節點之動量、質量與能量守恆方程式。 基本個案之分析顯示引擎操作於0.58-1.17 MPa，最大壓差約為0.1 MPa，工作流體溫度介於290-1200 K，再生器內部金屬溫度呈線性分佈，且效能達82.6%。引擎對外輸出功率為0.6 kW，熱效率為12.5%。 本論文分析了六個變更設計方案，包括調整冷卻器與再熱器之尺寸、調整冷卻水之溫度與流量，以及調整工作流體之質量，結果顯示縮小冷卻器可產生最大改善效果，可使引擎對外作功提高為0.8 kW，熱效率可達14.29%。 In this study, a basic design is proposed for an alpha-type hot air Stirling engine developed from a diesel engine. The engine is designed to be heated by the solar radiation from a concentrated solar collector and cooled by cooling water. The gas flow channels in the heater and cooler are constructed by finned and non-finned parallel metal plates, respectively. The regenerator design uses parallel wire screens. A third order model for the Stirling engine and a kinematic model for the slider- crank structure are developed and the two models are interconnected to simulate the operation of the whole Stirling engine. The Stirling engine model solves the mass, momentum and energy conservation equations for each control volume or node of the heater, cooler, regenerator and the hot and cold cylinders.
The simulation of the base design case reveals the cyclic operating conditions of the working gas and the solid temperatures. For the gas, the pressure ranged 0.58-1.17 MPa, the maximum pressure difference in the engine is about 0.1 MPa and the temperature ranged 290-1200 K. For the metal in the regenerator, the temperature distribution is linear and the effectiveness of the regenerator is 82.6%. The power output from the engine is 0.6 kW and the thermal efficiency is 12.5%.
In this study, six modified design cases are analyzed, including the adjustment of cooler size, heater size, cooling water temperature, cooling water flow rate and mass of working gas. The simulation results indicate that reducing the size of cooler provides the maximum improvement. The power output and the thermal efficiency can be raised to 0.8 kW and 14.29%., respectively.
