CFD-based parametric design optimization of a fuel-flexible jet-stabilized combustor for marine gas turbines

Kurzfassung

The transition of maritime transport toward low-emission, carbon-neutral operation requires fuel-flexible gas turbines ca pable of utilizing hydrogen and other alternative clean fuels. Within this context, the MARPOWER project is developing an in tercooled recuperative gas-turbine system for shipboard energy conversion, and this paper presents a CFD analysis of its jet stabilized, two-stage combustor. The study aims to obtain an optimized combustor design by assessing the influence of key geometric parameters on flow recirculation, flame stabilization, and emissions under elevated pressure and temperature condi tions representative of marine operation. A parametric design study was carried out, systematically varying nozzle pitch ra dius, premixing length, number of nozzles, and air-split ratios to identify configurations that enhance combustor performance. To ensure the reliability of the results while maintaining low computational cost, the CFD framework was verified through mesh-independence and feasibility studies. The results identi fied the nozzle pitch radius as a dominant parameter governing flame stability, whereas variations in premixing length provided only limited improvements due to the inherent nozzle geometry and operating principle. Reducing the pitch radius effectively mitigated flame–wall interactions and quenching, thereby lower ing thermal stresses. Moreover, adjusting the pilot-air fraction promoted richer operation and stronger recirculation, enhanc ing main-stage stabilization and enabling flexible-fuel operation. Theoptimizedconfigurationdemonstratedstablecombustion,low emissions, and a total pressure loss of approximately 5% across the combustor, ensuring high cycle efficiency and confirming the scalability of the jet-stabilized, two-stage combustion concept.