Numerical study of shock wave generated by hydrogen and oxygen detonation in a large shock tube

Blast wave has distinct characteristic parameters, which makes it difficult to replicate in experiments. Large shock tubes provide a low-cost and high-efficiency experimental platform to solve this problem, which can avoid the inaccuracy of the experimental results caused by the size effect in the small scale experiment. The specific driving methods of using large shock tubes to produce different kinds of shock waves are still worthy of further study. The feasibility of using large shock tube hydrogen-oxygen detonation to simulate explosion waves has been demonstrated by a large number of experimental studies based on large shock tunnels conducted by the Institute of Mechanics of Chinese Academy of Sciences. However, there is still a lack of research on blast wave simulation using large shock tubes. Therefore, a numerical simulation study of the generation and propagation process of shock wave generated by hydrogen and oxygen detonation in a large shock tube were conducted, and the reproduction of blast wave in a large shock tube was realized based on numerical simulation. Firstly, based on the designs of existing large shock tubes, a two-dimensional axisymmetric model of a large shock tube with driving tube, shock shaping section and variable angle outlet was established. A two-dimensional unsteady viscous compressible flow governing equations with the seven-steps reaction of hydrogen and oxygen mechanism was used to simulate the generation and propagation process of shock wave. The RNG k-ε model was selected as the turbulence model, and the two-dimensional transient coupling solver was used for numerical simulation. Due to the large scale of the model, turbulence has little effect on the far-field shock wave. Therefore, the finite rate component transport model was selected to couple the interaction between turbulence and chemical reaction, and a two-dimensional transient coupled solver was used. Secondly, with hydrogen and oxygen detonation as the driving method, the effects of initial driving conditions, low chemical reactivity gas mixing, and shock tube configurations on the formation of blast waves were studied. The characteristics of the wave form, the amplitude of the peak pressure and the trend of the positive pressure time were analyzed. Finally, based on the numerical simulation results, the control process of shock wave was simulated in a large shock tube and a good reproduction of the real explosion shock wave in a large shock tube was achieved using hydrogen and oxygen detonation as the driving method.