Effects of swirl injection on detonation wave dynamics and rotating detonation engine performance

• Novel Thrust Control Method: Swirl injection is established as a viable mechanism for active thrust modulation, allowing for control of engine power output by dynamically varying the injection angle. • Asymmetrical Effects: A clear performance asymmetry exists between positive and negative swirl angles. Angles that follow the wave direction yield higher wave velocities but require significantly longer stabilization periods than opposing angles of the same magnitude. • Significant Performance Trade-offs: The thrust modulation capability comes at a high cost, with large swirl angles reducing thrust by over 50% and specific impulse by 17%, while also substantially increasing the time required for the combustion to stabilize. • Practical Implementation Challenges: Applying this concept to a real engine presents major hurdles, including the risk of hydrogen leakage from moving injector parts and the inherent contradiction of adding mechanical complexity to an engine valued for its simplicity. Injection systems play a crucial role in the performance and stability of rotating detonation engines (RDEs), influencing detonation wave propagation, fuel mixing, and thrust generation. CFD provides an efficient and cost-effective method to study these complex phenomena, enabling the simplification of real-world injector behavior and the exploration of novel injection strategies. This study employs numerical simulations to investigate the effects of swirl injection on RDE operation, analyzing flowfield characteristics, combustion stability, and engine performance under varying injection angles. Small swirl angles ( ± 10°) minimally disrupt detonation waves, while larger angles ( ± 45°and ± 60°) introduce instability, including wave splitting and deflagrative losses. Swirl injection significantly reduces thrust (by over 50%) and specific impulse (by 17%). However, it offers a potential method for thrust modulation, with trade-offs in stabilization time and combustion efficiency. The study also highlights asymmetrical effects between positive and negative injection angles, with positive angles yielding higher wave velocities but requiring longer stabilization periods.