Characterisation of distributed combustion of reformed methanol blends in a model gas turbine combustor

In line with the United Nation Sustainable Development goal #7 (clean and affordable energy), new carbon-neutral fuels need to be investigated. Methanol is a promising alternative e-fuel to fossil fuels for the application in gas turbines. The paper presents a numerical study of the efficient use of green methanol using in a wet Brayton cycle with chemical recuperation. The 1D flame analysis shows the steam addition affects the oxidation pathway in terms of the H-atom abstraction reactions. The high fidelity LES results show that steam addition leads to distributed flames denoted by increased area of heat release and decrease of temperature gradient. The latter solely occurs in the inner shear layer. The conservative representation of Chemical explosive mode analysis (CCEMA) shows that the more flame is distributed, the more autoignition mechanism dominates the ignition process. It is found that autoignition mode becomes more dominant globally while the area featuring local extinction mode is lightly increased since the flame area is increased. The increasingly predominant role of autoignition is accompanied by the emergence of high-temperature reactions that generates HO₂ and OH radicals contributing the booming of radical pool.