Numerical modeling of a deflagrative-based pressure gain combustor integrated with an axial turbine

Pressure Gain Combustion (PGC) is a promising technology to significantly enhance the thermal efficiency of gas turbines by increasing stagnation pressure across the combustor. While most PGC research has focused on detonative-based systems such as Rotating Detonation Engines (RDEs), this study investigates an alternative deflagrative-based approach inspired by pistonless internal combustion engines. A comprehensive numerical analysis is presented, utilizing a dedicated simulation tool developed within the GT-Power environment to model the unsteady thermodynamic behavior of a deflagrative-based hydrogen-fueled PGC prototype. The combustor model was validated against high-frequency experimental data and then scaled to represent a real-engine application. To complete the system, a multi-stage axial turbine was specifically designed to accommodate the strongly pulsating outflow from the combustor. Despite significant fluctuations, the turbine maintained an average efficiency of 90% over the pulsation cycle. The combustor and turbine models were integrated into a full-cycle simulation framework, enabling the assessment of the complete system performance under transient operating conditions. The results indicate a cycle efficiency of 32.1%, representing a 7.7% improvement over conventional constant-pressure combustion systems. Despite being limited to a single operating condition, the modeling results are highly promising and provide a solid basis for future investigations. This work provides a viable alternative to detonation-based PGC technologies and shows potential for the feasibility of deflagrative-based systems for practical power generation applications. The modeling framework developed herein offers a scalable, computationally efficient tool for system optimization and supports further investigation of the proposed combustor concept.