Investigation initiation, transition and extinction of detonation instability

研究了爆轰不稳定性的起爆、过渡和消爆。其中一项研究旨在揭示一维非定常爆轰波前的非定常以及激波背后的爆炸性质。基于一维非定常爆轰的数值研究结果。研究了一维活塞支撑非定常爆轰与二维楔形斜致定常爆轰的类比关系，并将其应用于楔形斜致定常爆轰的波结构预测。指出了一维爆轰的具体特征。采用了符合Arrhenius速率表达式的一步化学反应和氢-氧燃烧机理的19个正向和反向化学反应。利用各反应模型研究了爆轰波前的非定常和激波后的爆炸特征。当采用详细的化学反应模型时，无论气体条件如何，都可以再现感应区。此外，流场中还出现了与第二次爆炸极限相关的特征，因为详细的化学反应模型可以再现OH自由基的产生和失活。另一项研究揭示了由于激波锋面和反应锋面相互作用而产生的纵向振荡特征。用简化的反应机制进行了一维和二维爆轰模拟，比较了它们的振荡。我用详细的反应机理来处理二维爆轰，以阐明在爆轰传播中起重要作用的横向振荡的特性。在此基础上，提出了横波强度作为理解混合材料性质的新指标。它使我们对安全工程中的爆轰控制及其在航空航天工程中的应用有了深入的了解。

I investigated initiation, transition and extinction of detonation instability.One of the studies aimed at revealing the unsteadiness of one-dimensional unsteady detonation wave front and the explosion nature behind the shock wave. Based on the results of numerical study of one-dimensional unsteady detonation. I investigated an analogy between one-dimensional piston-supported unsteady detonations and two-dimensional wedge-induced steady oblique detonations, and the analogy was applied to a prediction of the wave structure of the wedge-induced steady oblique detonation. The detailed features of one-dimensional detonation were indicated. A one-step chemical reaction obeying an Arrhenius rate expression and 19 forward and backward chemical reactions for hydrogen-oxygen combustion mechanism were used. The unsteadiness of the detonation wave front and the features of the explosion behind the shock were investigated using each reaction model. When the detailed chemical reaction model was used, the induction region can be reproduced regardless of gas conditions. Furthermore, the features related to the second explosion limit appeared in the flow field because the detailed chemical reaction model can reproduce the production and deactivation of OH radical.The other of the studies revealed the characteristics of longitudinal oscillations due to the interaction between the shock front and the reaction front. One- and two-dimensional detonation simulations were performed with a simplified reaction mechanism to compare their oscillations. I have treated two-dimensional detonations with a detailed reaction mechanism to clarify the characteristics of transverse oscillations that play a prominent rule in detonation propagation. According to the results, transverse wave intensity was newly proposed for a guide to understand the mixture properties. It gave us the insight into control of detonation in safety engineering, and application in aerospace engineering.