关键词: 大涡模拟, TTGC, 超黏性, 激波, 边界层, 爆震

Abstract: Coupled with the Smagorinsky sub-grid model and a thickened flame model, a high-order large eddy simulation solver for the reactive flow is developed in this paper to study the effect of the boundary layer on the shock/flame interaction. The key to this solver is the adoption of an artificial hyperviscous model and a space-time third-order Two-step Taylor-Galerkin Compact (TTGC) scheme. Calculations of the 1-D Shu-Osher problem and the 2-D shock/bubble interaction demonstrate the precision of the solver in identifying shock waves, contact discontinuities and turbulent flow. The simulation results are in good agreement with the experimental data. The interaction between the 2-D shock/flame and the boundary layer in an end-wall shock tube are calculated. The results show that a shock bifurcation phenomenon occurs due to the interaction between the shock and the laminar boundary layer, and the propagation speed of the triple bifurcation point experiences three regimes of horizontal uniform motion, linear growth of small slope and rapid growth of large slope, which reveals the mechanism of flame acceleration resulting from shock bifurcation. The recirculation zone of shock bifurcation plays the role of a flame holder as the reactive flow in the bifurcation can provide continuous heat for the motion of the shock wave, and the flame front closely follows the bifurcated shock and spreads forward quickly in the local supersonic region. A comparison of methane combustion in our simulation and ethylene reaction from other research under the same condition shows that the location of the detonation point are both behind the Mach stem and the variation trend of the heat release rate is also consistent with each other, but detonation occurs earlier for the ethylene.

Key words: large eddy simulation, TTGC, hyperviscous, shock wave, boundary layer, detonation