Research on the Propagation Characteristics of Pulse Detonation Waves in Fan-Shaped Tube

The fan-shaped pulse detonation combustor (PDC) can enhance the cross-sectional utilization of multi-tube pulse detonation engines and improve the performance of pulsed detonation engine. However, compared with the traditional circular cross-section PDC, the formation and propagation characteristics of the detonation wave in the fan-shaped cross-section PDC have changed. In order to study the working characteristics of the fan-shaped PDC, the three-dimensional calculation model for the fan-shaped PDC was established. Using the three-dimensional numerical simulation method, the initiation process of the single-tube fan-shaped cross-section PDC was calculated, and the generation and propagation characteristics of the internal detonation waves were analyzed. The research results show that in the fan-shaped PDC, the propagation mode of the detonation is quite different from that of the circular straight pipe PDC. Due to the curvature change of the fan-shaped cross-section, the wave surface of the detonation wave is no longer perpendicular to the PDC wall, and the wave surface takes on a concave butterfly shape. The upper arc surface flame speed is comparable to that of the side surface flame and is higher than that of the lower arc surface. The propagation process of the detonation wave is a gradual shift from the upper arc surface to the lower arc surface, and finally stabilizes at a tilted state in the middle. Furthermore, there is a gradient of pressure along the circumferential direction within the fan-shaped cross-section PDC. The peak pressure on the lower arc side can be 14% higher than that on the upper arc side.