Effects of silicone rubber and aerogel blanket-walled tubes on H2/Air gaseous detonation

The experimental study of hydrogen-air detonation was performed in a 6.3-m-long circular cross-section tube, the rear section of which was walled by silicone or aerogel material. Mixtures of 25% or 29.6% hydrogen with air by volume with an initial pressure of 0.1 MPa and temperature of 293 K were used in the experiments. A short Shchelkin spiral was fixed at the tube head to accelerate the deflagration-to-detonation transition. The flame and pressure wave propagation velocities were measured by ion probes and pressure transducers, respectively. The detonation regimes and velocities of flame propagation in walled tubes of different materials were compared. It was found that it is difficult for a silicone rubber-walled tube to reduce the intensity of the detonation wave. In this case, for the stoichiometric mixture, a reduction in the propagation velocity by 5% and the pressure peak by 12% was recorded in order to compare those parameters in a stainless smooth tube. An aerogel blanket wall has a strong ability to reduce the intensity of the detonation wave with the peak pressure decreased by 35% for the stoichiometric hydrogen-air mixture. The attenuation of the steady detonation wave can occur in the aerogel blanket-walled tube under the present experimental conditions. This is because of the effective suppression of transverse waves by interaction with the aerogel wall; then, the generation of stable detonation cells is no longer possible, and thus, the shock wave and flame front are decoupled, and detonation is suppressed.