Weak and strong ignition of hydrogen/oxygen mixtures in shock-tube systems

作者：Grogan Kevin P; Ihme Matthias^*

来源：Proceedings of the Combustion Institute, 2015, 35(2): 2181-2189.

DOI：10.1016/j.proci.2014.07.074

• Shock-tube
• Weak ignition
• Heat transfer
• SWACER
• DDT

Detailed simulations of hydrogen/oxygen mixtures are performed to study weak and strong ignition regimes in a shock-tube system. An adaptive mesh refinement (AMR) algorithm in conjunction with a detailed chemistry representation is used to resolve physically relevant features such as the viscous boundary layer, the shock bifurcation region, and ignition kernels. The simulations employ a second-order accurate Navier-Stokes equations solver that is modified to include finite-rate reaction chemistry, wall-heat transfer, and detailed mass, thermal, and viscous-diffusion-transport properties. The operating conditions considered in this study span the thermodynamic state-space in the weak and strong ignition regimes. The treatment of wall-heat transfer is found to significantly alter the characteristics of ignition. The computations show that the mixing of the thermally stratified fluid, which carries different momentum and enthalpy, introduces inhomogeneities in the core region behind the reflected shock. These inhomogeneities act as localized ignition kernels. During the induction period, these kernels slowly expand and eventually transition to a detonation wave, rapidly consuming the unburned mixture. Effects of the reaction chemistry on the ignition behavior are examined by considering two different reaction mechanisms. A detailed analysis is performed to show that the transition from ignition kernel to detonation is well described by the SWACER mechanism.

• 出版日期2015