Experimental study on detonation propagation characteristics of hydrogen-nitrous oxide at stoichiometric and fuel-lean conditions

Knowledge of detonation propagation characteristics of H-2-N2O mixtures is crucial for industrial safety and development. In this study, the detonation propagation characteristics of H-2-N2O mixtures with different equivalence ratios (phi = 0.4, 0.6, and 1.0) in three tubes (d = 14.5, 19.5, and 28.6 mm) were investigated experimentally. Some dominant chemical lengths were evaluated together with cell size and normalized average velocity. The results show that the periodic oscillation of local velocity is more intense as approaching the limits. Below the limits, the detonation fails and decays rapidly to a "low velocity" regime. The tube scale and initial pressure determine the velocity deficit and the minimum detonation velocity shows no obvious trend on the mixture composition and tube scale. Scaling analysis illustrates that the dimensionless parameter d/Delta(1) and normalized average velocity show a single exponential growth trend. Notably, the detonation tends to decay earlier at phi -1.0 than phi - 0.4 or phi - 0.6. Besides, fuel-lean mixtures (q, = 0.4 and 0.6) and stoichiometric mixtures (phi = 1.0) share similar critical pressure. It can be obtained that a linear relationship exists between the cell size and the induction length. The cell size data shows that the cell size of phi = 0.6 is the smallest, which agrees with the results of the induction length calculated. It is also demonstrated that the maximum value of heat release ratio peak is at q, = 0.6. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.