Numerical investigation of combustion, performance, and emission attributes of premixed ammonia-hydrogen/air flames within a swirl burner of a gas turbine

This study investigates numerically combustion attributes and NOx formation of premixed ammonia-hydrogen/air flames within a swirl burner of a gas turbine considering various conditions of hydrogen fraction (HF: 0%, 5%, 30%, 40%, and 50%), equivalence ratio ( φ : 0.85, 1.0, and 1.2), and mixture inlet temperature (T in : 400 - 600 K). The results illustrate that flame temperature increases with hydrogen addition, from 1958 K for pure ammonia to 2253 K at 50% HF. Raising the inlet temperature from 400 K to 600 K markedly enhances combustion intensity, resulting in an increase of the Damköhler number (Da) from 117 to 287. NOx levels rise from ∼1800 ppm (0% HF) to ∼7500 ppm (50% HF), and peak at 8243 ppm under lean conditions ( φ = 0.85). Individual NO, N 2 O, and NO 2 emissions also reach maxima at φ = 0.85 with values of 5870 ppm, 2364 ppm, and 10 ppm, respectively, decreasing significantly under richer conditions (2547 ppm, 1245 ppm, and 5 ppm at φ = 1.2). These results contribute to advancing low-carbon fuel technologies and highlight the viability of ammonia-hydrogen co-firing as a pathway toward sustainable gas turbine operation.