本論文的研究重點主要在發展介觀型熱光電系統（Meso-scale thermophotovoltaic system, TPV）之小型燃燒器研發與應用，其目標主要在改進其低亮度和不完全燃燒的相關問題，本論文重點放在燃燒器的設計與研究上,其燃燒器設計上，運用熱再生迴流管（heat-regeneration reverse tube）和提升空氣與氣態燃料混合之多孔性介質（porous-medium）燃料噴注裝置一起用來改善這些問題；其中，在TPV系統中利用一個遠紅外線陶瓷管(ZrO2)當作輻射器(Emitter)，並應用熱再生迴流管的設計，藉此改變流場結構，進而使火焰更貼附於燃燒器壁面以提升輻射器表面溫度，另外，改變熱氣的行進方向來達成再次加熱輻射器壁面，進而使壁面具有更高且均勻的溫度和亮度，因此火燄可以完全被限制在燃燒器中；除此之外，也利用金屬多孔性介質燃料噴注裝置之特性，增加空氣與燃料之混合，進而達到穩住火焰的效果；並引入實驗分析與數值模擬技術對熱光電動力系統之小型燃燒器作深入之研究。
此外，本文數值模擬主要運用計算流體流動模擬搭配二階(two-step)的化學燃燒反應機制來運算求解，進而從中探討與分析更近一步之空氣-氣態燃料混合場（fuel-air mixing）與火焰穩駐機制（flame stabilization mechanisms）之現象。當燃燒器物理尺度縮小時，因為高面體比(surface-to-volume ratio, S/N)造成火焰與壁面接觸的面積增加，而加強了壁面熱傳效應，也導致冷熄(flame quenching)現象的產生，進而使這些相關之熱管理(thermal conditions)問題變得非常重要，因此本文也運用了數值模擬技術去探討與分析各種不同燃燒器壁面熱傳條件下，例如不同燃燒器壁面之熱傳導系數所造成之相關流場特徵及火燄燃燒現象去探討與分析。其結果證實了小型燃燒器搭配迴流管（heat-regeneration reverse tube）和多孔性介質（porous-medium）燃料噴射裝置會因為熱空氣膨脹擠壓效應和出口渦流強度減少而使管口後火燄內縮且貼附於燃燒器壁面，因此可改善因不完全燃燒和太短的燃氣滯留時間(residence time)所造成輻射器(Emitter)的亮度不均勻或是表面溫度太低的情形，進而可以促進發亮均勻和增加表面溫度而使火燄可完全被限制在燃燒器內。相同地，其數值模擬結果也指出了控制相關氣體流率、熱損失條件及維持恰當的熱管理可持續使火燄在燃燒器內穩定燃燒。因此，藉由實驗與數值模擬結果之分析，可獲得最佳化之相關設計條件及參數，進而增加對此熱光電系統之小型燃燒器的燃燒原理與火焰穩定機制的了解，也提供日後在光熱電(TPV)能源系統的設計參考與選擇。

In this dissertation, methods for enhancing intensity and uniformity of the combustion chamber wall (emitter) illumination through combustion and thermal management designs of the combustor in a miniature TPV system are proposed, discussed, and demonstrated. The proposed miniature TPV system consists of a swirling combustor with the infrared thermal tube (ZrO2) acting as the emitter, a heat-regeneration reverse tube, and mixing-enhancing porous-medium fuel injection, which improves the low non-uniform illumination or incomplete combustion problems associated with conventional miniature TPV systems. A heat-regeneration reverse tube is used to enforce the swirling flame attaching to the inner wall of the emitter by pushing the swirling recirculation zone (negative axial velocity region) back into the combustor and simultaneously redirecting the exit hot product gas for reheating the outer surface of the emitter. The porous-medium fuel injector is used as a fuel/air mixing enhancer and a flame stabilizer to anchor the flame.
In addition, the two-step global reaction mechanism was used to compute the chemical reactions of the reacting flows. Experiments and numerical simulations are performed to analyze the details of the flame structure and flame stabilization mechanism inside the meso-scale TPV combustor with and without a reverse tube. Besides, these thermal conditions have strong effects on the combustion especially when the chamber dimension goes smaller and the ratio of surface area to volume (S/V) becomes larger. Enhanced heat loss through the chamber wall to the ambient due to increased S/V ratio, may lead to the thermal quenching of the meso-scale combustor. Therefore, the effect of various heat transfer conditions on chamber wall, e.g. with different wall heat conductivity and combustion chamber dimension size on the combustion are delineated and discussed by numerical simulation. Results indicate that the proposed swirling combustor with a heat-regeneration reverse tube and porous medium can improve the intensity and uniformity of the combustion chamber (emitter) illumination, and can increase the surface temperature of the chamber wall. Correspondingly, the numerical results also indicated that the stable combustion in a meso-scale TPV combustor may be sustained through control of the mass flow rate, heat loss conditions and proper thermal conditions. From the systematic numerical and experimental analysis, suitable operational parameters for the meso-scale TPV combustor are suggested, which may be used as a guideline for meso-scale TPV combustor design.

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