In the context of both a continuously increasing energy demand and an ever more pressing worldwide necessity of reducing pollutants emissions due to climate requirements, hydrogen represents an interesting alternative to natural gas for heavy-duty gas turbines (HD-GT) power supply. Its high reactivity widens indeed the flammability limits and enhances flame propagation: this results in a more efficient combustion giving lower emissions of greenhouse gases. However, since pre-existing technologies designed for natural gas have shown a lack of adequacy to provide flame stabilisation and safe operating conditions, it comes the need for retrofitting of already existing geometries. From this perspective, CFD simulations pose a powerful analysis tool.