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、熱損失與爆震胞格相對於通道尺寸（λ/d）等機制競爭影響，反應波並依條件呈現穩定爆震、過渡型態、緩燃與熄滅等傳播模式。本方向以管徑、當量比與 λ/d 建立傳播模式圖，解析窄通道中特有的反應—震波耦合結構，並以這些臨界資料支援小尺度脈衝爆震元件等微推進原型的設計，以及窄通道燃燒與爆震安全評估。In confined geometries such as microtubes, thin channels, and gaps, flame acceleration and DDT are governed by competing mechanisms — wall boundary-layer effects, heat loss, and the detonation cell size relative to the channel dimension (λ/d) — and reaction waves span steady detonation, transitional states, deflagration, and quenching depending on conditions. The work maps these propagation modes in channel dimension, equivalence ratio, and λ/d, resolves the reaction–shock coupling structures distinctive to narrow channels, and uses the near-limit data to inform microscale pulsed-detonation prototypes and combustion and detonation safety assessment in narrow passages.
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／氧氣系統改變管徑、間隙寬度、當量比與氮氣稀釋比例。以高速紋影攝影解析震波結構、化學發光攝影擷取反應前緣，並與壓力感測器及光電二極體進行奈秒精度同步；再從連續影像提取反應前緣速度歷程、辨識反應波—震波複合結構，並以影像測溫法量測反應區溫度分佈。Test sections include round glass/quartz microtubes (0.25–3 mm ID), thin rectangular channels, and sub-millimeter planar gaps (Hele-Shaw type), with sudden-expansion sections or zigzag sidewalls, using ethylene/oxygen and propane/oxygen while varying tube diameter, gap width, equivalence ratio, and nitrogen dilution. High-speed schlieren imaging resolves shock structures and chemiluminescence imaging captures reaction fronts, synchronized with pressure transducers and photodiodes at nanosecond accuracy; sequential images then yield reaction-front velocity histories, the spatial features of reaction–shock composite structures, and reaction-zone temperature fields via image pyrometry.