Experimental study on the effect of fuel supply methods on pulse detonation combustor performance

Pulse Detonation Combustors (PDCs) represent a transformative propulsion technology capable of achieving substantial thermodynamic efficiency gains through constant-volume combustion and self-pressurization. However, conventional adaptive fuel supply methods remain fundamentally limited by their passive coupling with chamber dynamics, resulting in uncontrolled injection during critical phases such as deflagration-to-detonation transition (DDT) and exhaust. To overcome these limitations, this study introduces an actively controlled low-pressure intermittent fuel supply system, systematically examining its performance relative to conventional adaptive fueling in a gasoline/air U-bend PDC. Experimental results confirm stable detonation across 10–30 Hz under both strategies, yet the intermittent method significantly shortens the DDT distance from 733 mm to 616 mm with increasing frequency. Moreover, it enables precise temporal fuel management, yielding an 8–14 % reduction in fuel consumption while maintaining detonation stability. A notable innovative finding is the consistently shorter and stable blue flame observed at the combustor outlet under intermittent supply, indicating more complete combustion and enhanced energy release—a direct result of suppressed over-rich mixture formation during non-optimal cycles. These results underscore the critical role of active injection synchronization in detonation cycle optimization and provide a theoretical basis for advanced control strategies in next-generation PDCs.