臨界爆震研究以小尺度反應波傳播、火焰加速與爆震轉換為核心，探討幾何尺度、壁面效應、壓縮波與化學反應耦合如何共同決定傳播模式。Near-limit detonation research focuses on small-scale reaction-wave propagation, flame acceleration, and deflagration-to-detonation transition, examining how geometry, wall effects, compression waves, and chemistry jointly determine propagation modes.
在微管、薄通道與狹縫等受限幾何中，火焰加速與爆震轉換（DDT）同時受壁面邊界層、熱損失，以及爆震胞格相對於通道尺寸（λ/d）等機制競爭影響。本方向長期累積臨界條件下的實驗證據，逐步釐清各機制的作用條件與相對重要性，並建立適用範圍明確的物理理解。In confined geometries such as microtubes, thin channels, and gaps, flame acceleration and DDT are jointly governed by competing mechanisms — wall boundary-layer effects, heat loss, and the detonation cell size relative to the channel dimension (λ/d). The work accumulates experimental evidence under near-limit conditions over time, progressively clarifying the operating conditions and relative importance of each mechanism toward a physical understanding with clearly defined validity bounds.
在受限幾何中，反應波依條件呈現出多種傳播模式，可橫跨穩定爆震、各類過渡型態、緩燃與熄滅。本主題以管徑、當量比與 λ/d 建立傳播模式圖，作為理解臨界行為的系統性框架，並持續解析窄通道中特有的反應—震波耦合結構。In confined geometries, reaction waves exhibit a range of propagation modes depending on conditions, spanning steady detonation, various transitional states, deflagration, and quenching. We organize these into regime maps in channel dimension, equivalence ratio, and λ/d as a systematic framework for understanding near-limit behavior, and continue to identify distinctive reaction–shock coupling structures in narrow channels.
受限幾何中反應波傳播與爆震極限的研究資料，可支援小尺度脈衝爆震元件等微推進原型的設計，並為窄通道、狹縫等場合的燃燒與爆震安全評估提供實驗依據。本方向未來將進一步整合機制研究與量測資料，朝實用化微推進構型與系統化爆震安全評估推進。Reaction-wave propagation and detonation-limit data in confined geometries can inform the design of microscale pulsed-detonation device prototypes and provide an experimental basis for combustion and detonation safety assessment in narrow channels and gaps. Going forward, the work will further integrate mechanism studies with measurement data, progressing toward practical micro-propulsion configurations and systematic detonation-safety assessment.
測試段涵蓋圓形玻璃／石英微管（內徑 0.25–3 mm）、薄型矩形通道與次毫米平面狹縫（Hele-Shaw 型），並搭配突擴截面或鋸齒壁面，以乙烯／氧氣與丙烷／氧氣為燃料系統，系統改變管徑、間隙寬度、當量比與氮氣稀釋比例。Test sections include round glass/quartz microtubes (0.25–3 mm ID), thin rectangular channels, and sub-millimeter planar gaps (Hele-Shaw type), combined with sudden-expansion sections or zigzag sidewalls, using ethylene/oxygen and propane/oxygen as fuel systems while varying tube diameter, gap width, equivalence ratio, and nitrogen dilution.
以高速紋影攝影解析震波結構，以化學發光攝影擷取反應前緣動態，兩者搭配壓力感測器與光電二極體進行奈秒精度同步觸發，完整記錄反應波與震波的耦合過程。High-speed schlieren imaging resolves shock-wave structures and chemiluminescence imaging captures reaction-front dynamics, both synchronized with pressure transducers and photodiodes at nanosecond accuracy to provide a complete record of the coupling between reaction waves and shock waves.
從連續影像序列提取反應前緣速度演化歷程，辨識反應波—震波複合結構的空間特徵，並透過影像測溫法量測反應區溫度分佈。Reaction-front velocity evolutions are extracted from sequential image series, spatial characteristics of reaction–shock composite structures are identified, and reaction-zone temperature distributions are measured via image pyrometry.