轴向侧向膨胀与通道曲率耦合影响下的旋转爆震波传播特性研究

To clarify the influence of axial lateral expansion on the propagation characteristics of detonation waves in curved channels， experimental study was conducted in confined and semi-confined curved channels with an inner radius of 45 mm and the mixture heights of 10 mm， 20 mm， and 30 mm. Ethylene and a nitrogen-oxygen mixture with a dilution ratio of 0.5 were utilized as fuel and oxidizer，respectively. The effects of lateral expansion on the peak pressure， the propagation velocity， and the propagation modes of detonation waves at different equivalence ratios were investigated. The results indicated that under the influence of lateral expansion， the deficits of wave velocity and peak pressure increased， especially under both fuel-lean and fuel-rich conditions. As the mixture height decreased， the deficits were further amplified. Based on the D_n/D_CJ variations along the inner wall of the curved channel，five propagation modes were observed after the stable detonation waves entering the curved channels，i.e.，a stable mode，a critical mode，a weakly unstable mode，a highly unstable mode，and a deflagration mode. The critical inner radius for stable propagation in a confined curved channel was 9.07—10.55 times the average cell width. After introducing the lateral expansion，a smaller channel curvature helped reduce the deficits and enhances the ability to resist lateral expansion. Therefore，the critical inner radius in a semi-confined curved channel increased to 15.62—18.32 times the average cell width to maintain stable propagation.