环形爆震波聚焦起爆

本文对三种带不同结构形式的环形预爆管的爆震发生器进行了数值模拟，来研究环形爆震波聚焦起爆现象及其气动特性。数值计算采用多组分理想气体详细的化学反应机理、二维轴对称非定常流动的Navier-Stokes方程来模拟化学动力学和流体动力学过程。研究发现用低的点火能量对环形预爆管中的燃料和氧化剂点火产生层流火焰，层流火焰在狭窄管壁的作用下完成爆燃向爆震转捩，形成环形爆震波，环形爆震波在聚焦腔经过反射、汇聚，最终引爆主爆震室中的可燃混合物；并对稳定爆震的距离和强度进行了对比研究。通过分析对环形爆震波衍射、反射、聚焦的气体动力学特性及复杂波系发展规律有了更深的认识，为进一步试验提供参考。

Detonation initiation in a duct via imploding annular detonation

Computational simulations on detonation duct with different annular pre-detonators were carried out to study the phenomena, mechanism and gas dynamics characteristic of annular detonation imploding and focusing. Two-dimensional axisymmetric and unsteady Navier-Stokes equations were numerical simulated and detailed chemical reaction kinetics of hydrogen/air mixture was used. The results of numerical simulation show that laminar flame generated by low energy ignition in annular pre-detonator accelerates under the narrow channel, and then forms annular detonation via deflagration-to-detonation transition. Annular detonation detonates the combustible mixture in the main detonation chamber after reflection, imploding and focusing at the axis. Contrastive research on the distance and intensity of stable detonation are analyzed. Through calculation and analysis, deep understanding on the aerodynamics characteristic of annular detonation wave diffraction, reflection and imploding and the development of complex wave in the transitional region were obtained, which provided theory basis for detonation initiation and useful information to further experiment.