Experimental Research on Detonation Cell Size of a Purified Biogas-Oxygen Mixture

Interest in alternative and renewable energy sources has risen significantly in recent years. Biogas is a prime example of a promising, alternative fuel that might be a possible replacement for fossil fuels. It is a mixture consisting mainly of CH4 and CO2 with various additions. Biogas is easily storable and as such is a more reliable and stable source of energy than solar and wind sources, which suffer from unreliability due to their dependence on weather conditions. In this paper, the authors report experimental results of detonation of a biogas-oxygen mixture. The composition of the biogas was 70% CH4 + 30% CO2 and the experiments were carried out for a range of equivalence ratios (Φ = 0.5 ÷ 1.5) and initial pressures (0.6 ÷ 1.6 bar). The aim of the research was to analyze the cellular structure of detonation. The soot foil technique was used to determine the width of the detonation cells (λ). The conducted experiments and subsequent analysis of the detonation cell size confirm that both the increase in the initial pressure of the mixture or move away from stoichiometric (Φ = 1) composition is accompanied by a decrease in the width of the detonation cell. The authors also argue that due to the unstable cellular structure of the detonation, it is insufficient to report only the average cell size. Instead, the researchers propose more detailed statistical description assured values.

Estimation of the energy of detonation initiation in a hydrogen-oxygen mixture by a high-velocity projectile

The paper presents the results of a numerical study of the initiation of oblique detonation modes by a high-velocity projectile moving in an argon-diluted hydrogen?oxygen mixture. The simulation of oblique detonation wave modes showed that calculated and experimental flow patterns agree. The calculated detonation cell size agreed with experimental data. For the initial pressure Pst = 121 kPa and Pst = 141 a series of calculations were carried out for a different projectile diameters. The detonation initiation energy was estimated, and the results were compared with theoretical models.