Rapid Minimum Tube Diameter Measurement and Comparison with Detonation Cell Size

摘要

A series of methane-oxygen detonation experiments are completed to determine the minimum detonation propagation diameter. Upstream velocity measurements show Chapman-Jouguet velocities within 3% of expected values based on fill pressures. Velocity deficits are seen to increase as tube diameter decreases. A maximum velocity deficit of 10-13% is measured. The minimum detonation propagation tube diameter is compared with historical soot foil cell size data. The minimum tube propagation diameter is determined using a custom setup with in-house built ion probes. Comparison of these two measurement methods are presented to confirm the relationship between them. A calculated cell size based on the minimum diameter shows good agreement with historical data for varying levels of nitrogen dilution. Results show the viability of this method for making meaningful detonation measurements which are free from researcher bias. A consistent relationship yields a simple and rapid detonation length scale measurement technique.