Numerical and experimental comparison of H2/air flame–shock interaction

A high-fidelity three-dimensional numerical simulation is performed to replicate the experimental shock tube setup of the ICARE laboratory, where a hydrogen–air flame–shock interaction (FSI) is studied. Following the experimental procedure, a lean flame ($\varphi =0.8$) is ignited at the closed end of a rectangular channel before a shock wave, traveling at a Mach number of $M_s=1.9$, is triggered from the opposite side. The FSI occurs when the shock wave encounters the laminar flame in the visualization window, where experimental schlieren images have been captured. To reproduce this experiment, the fully compressible Navier–Stokes equations are solved using the San Diego mechanism, which includes nine reacting species (excluding nitrogen oxides) and 23 kinetic reactions. Species diffusion is modeled using the Hirschfelder–Curtiss model combined with thermal diffusion (Soret effect). Additionally, gravity is accounted for in the simulation.

The three major observations of the experiment were well captured by the numerical simulations through a comparison of experimental and numerical schlieren images: the laminar flame propagation and its interaction with adjacent walls; the first FSI, which leads to the formation of Richtmyer–Meshkov instabilities (RMI); and finally, the second FSI, occurring when the reflected shock wave travels back towards the entrance, generating reactive boundary layers and multiple shock interactions within the funnel of fresh gases produced by the RMI.