Effect of Architecture of a Combustor on the Rotating Detonation Combustor Perfromance

Effect of Architecture on the Performance of a Rotating Detonation Combustor Venkat E. Tangirala, Craig A. Nordeen and Anthony J. Dean CPEC Technologies, Schenectady, NY Abstract A detonation-based thermodynamic cycle is considered superior to a constant pressure deflagration flame-based cycle such as a Brayton cycle, because it enables faster combustion of fuel-air mixture in a shorter combustor. As the detonation occurs in a constant volume thermal reaction zone attached to the leading shock wave, pressure-rise occurs in the reaction zone. This resultant pressure gain in a detonation combustion process can improve the thermal efficiency of these propulsion/power-generation devices. The present investigation of RDE focuses on the impact of architecture on Rotating Detonation Combustor (RDC) performance, focusing on two configurations: (i) a novel RDC configuration with X-shaped combustor cross-section, namely RDCX and (ii) a previously investigated RDC configuration with annular combustor cross-section, namely RDCA. The objective is to develop methodologies for advanced design and assess operability and performance metrics such as detonation frequency, pressure drop, swirl, and combustion efficiency. Using validated 3D unsteady CFD simulations, the study evaluates these architectures under identical operating conditions to determine their suitability for propulsion applications. The analysis emphasizes optimizing combustor geometry to improve fuel-air mixing, pressure gain, and swirl attenuation for enhanced thermal efficiency. In the present study, 3D unsteady reacting flow CFD simulations are performed for base case RDCX and RDCA geometries. RDCX operability (occurrence of detonations at the conceptual design conditions) and performance parameters (net pressure drop, frequency of operation and combustion efficiency) are assessed. For the base case RDCX geometry, a quasi-steady triplet detonation structure was predicted whereas for RDCA, a single head detonation was predicted with operating frequency of 5.8 kHz. For the same operating conditions, RDCX simulations show a three head detonation structure with an operating frequency of 20 kHz. RDCX predictions show more attenuated swirl component at the combustor exit relative to RDCA. RDCX operability at design conditions is more stable relative to RDCA. Future work will focus on refining geometry and injection strategies to further enhance performance metrics and ensure robust operation across a broader parameter space.