在超音速流場中，燃燒室中的氣流滯留時間過短，燃燒反應難以進行，因此需在燃燒室內設置凹槽駐焰機構以提升燃料與氣流之混和效率，燃料與氣流的混合及燃燒情況皆會受到這些超音速流場中的現象所影響。本研究利用先前於震波風洞中架設之粒子影像測速儀系統來觀察L/D=4、後壁面角度為 22.5 度且深度為10 mm的開放式凹槽，針對不同前壁面角度(90度、45度、30度、22.5度)及不同大小構型(L/D=4、前壁面斜角45度、深度10 mm、16.5 mm)之凹槽駐焰器流場，以觀察不同角度和大小構型對於凹槽駐焰器在超音速流場下，流場內剪切層、低速回流區和主流場之間交互作用下如何影響和產生不同的流場情況。
本研究使用粒子影像測速系統（Particle Image Velocimetry，PIV）於震波風洞中進行凹槽駐焰器內流場之量測，風洞可運作時間約為0.8 ms，實驗開始前使用流體化床預先將示蹤粒子流化，使粒子與氮氣預先混合後，噴注進入流速為馬赫數2的自由流的測試段中，再利用邏輯閘控制高速攝影機及兩道雷射之時序拍攝出能進行PIV運算之時間間隔約為500 ns的兩張瞬時影像。在先前的流場觀測中發現凹槽內部流場，存在強烈的三維流動影響。因此，本研究通過減少凹槽深度，進一步減少凹槽寬深比和長寬比，以降低過於強烈的三維影響。
利用震波風洞所架設之超音速 PIV 系統，對凹槽駐焰器流場進行速度計算後，再利用Q準則(Q criterion)、Lambda-2 準則( λ2 criterion)等渦流分析方法， 並在低速迴流區範圍內進行環流計算，分析凹槽迴流區的流場狀態。在L/D=4、前壁面90度流場觀測中，出現兩個不同向的主次迴流區流場型態。前壁面斜角45度中則是出現單一個主迴流區流場。前壁面斜角30度和22.5度流場中，由於前壁面更加傾斜造成氣流進入凹槽後直接貼附於凹槽前壁面，因此前方靠近轉折處並未有足夠空間產生渦漩迴流區域，流場中則無發現渦漩迴流區存在。在改變前壁面角度的參數下，45 度凹槽駐焰器流場中，凹槽內部僅出現單一主迴流區結構，原因為流場中並無太多干擾渦漩產生，低速區流場中的渦漩強度，代表流場旋轉特性、強度的環流量分析，擁有較高的值。在增加凹槽構型大小深度為16.5mm 的凹槽駐焰器流場中，相較於一般構型下，加大構型凹槽內部將穩定出現單一主迴流區流場。在凹槽深度改變大小構型設計下，單一迴流區流場結果中，兩者擁有相近的渦漩結構和強度。但兩者間因凹槽內部空間不同，而影響內部迴流區的形成，以致一般構型部分出現無迴流結構之流場。期望未來能將這些結果應用於熱燃實驗中，作為穩定駐焰機制的凹槽駐焰器設計參考。

The research investigates the application of a supersonic Particle Image Velocimetry (PIV) system in a shock wind tunnel to examine the supersonic cavity flow field of cavity flame holders with different angled front walls (90°、45°、30° and 22.5°) and different configuration sizes (L/D=4, front wall angle 45°, depths of 10 mm and 16.5 mm). The shock tunnel generates a Mach 2 freestream with a test time of 0.8 ms in the test section. To mitigate the influence of the three-dimensional effects on the flow field, the study decreased the cavity depth, thereby reducing the width-to-depth ratio and length-to-width ratio. The study employs various flow field analysis methods to compare and explore the flow field conditions.
Experimental results reveal that L/D=4 and a 90° front wall angle, two primary and secondary recirculation zone flow patterns with different directions were observed. The shear layer's influence compresses the primary recirculation zone, leading to lower vorticity and circulation values. In the 45° front wall angle, a single primary recirculation zone flow field appeared. In the 30° and 22.5° flow fields, no vortex recirculation zones were found in these flow fields. Cavity with an increased configuration size and a depth of 16.5 mm, stably existed a single primary recirculation zone flow field. Under different cavity depths, both configurations had similar vortex structures and intensities.

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