Parametric CFD Analysis of Pure Hydrogen and Hydrogen-Blended Combustion in a Canonical Gas Turbine Combustor

The transition to hydrogen-fueled gas turbines is vital for decarbonising power systems, especially in space- and weight-constrained applications such as offshore FLNG and FPSO. While hydrogen offers zero-carbon emissions at the point of use, its use in gas turbines faces technical challenges due to high flame speed, flammability limits, low energy density, and high flame temperature. These increase the risks of flashback and NOₓ formation, especially when retrofitting existing combustors. Developing hydrogen-ready combustors for both pure hydrogen and blends is an ongoing research area. This study investigates a can-type, annular gas turbine combustor for use with pure hydrogen and blends. Using CFD simulations in ANSYS Fluent, it analyses flow, flame, temperature, and stability across hydrogen ratios from 0% to 100%. The model employs RANS equations, a realizable k–ε turbulence model, non-premixed combustion, and species transport; thermal radiation is modelled with the P-1 method, and NOₓ with the Zeldovich mechanism. Results show hydrogen increases flame reactivity, shortens flame length, and enhances recirculation zones, maintaining stability at ~50% hydrogen. Higher fractions increase flame temperature and velocity, increasing the risk of flashback. Pure hydrogen produces compact, high-temperature flames that require advanced designs for stability. Model predictions match experimental and published data from NASA, Siemens SGT-800, GE LM6000, and Kawasaki, confirming credibility. This CFD assessment offers insights into hydrogen combustor design, supporting the move towards hydrogen-ready turbines and low-carbon offshore power generation.