Numerical Simulation of Combustion Process and Emission Assessment of Ammoniac/Air Mixture in Gas Turbines Combustion Chamber

This study numerically simulated the influence of equivalence ratio and mass flow rate on the characteristics of ammoniac/air flames and NOx emissions in a gas turbine-like combustion chamber. The equivalence ratio $(\phi)$ and mass flow rate (Q) were varied, where $\phi=0.2-0.5$ and $\mathrm{Q}=0.6-1.2 \mathrm{~g} / \mathrm{s}$, respectively. The numerical method employed a non-premixed flame model and $k-\varepsilon$ turbulence model to simulate the combustion process at a fixed power of 60 kW. The results indicate that at a given equivalence ratio $(\phi=0.5)$, increasing Q leads to an increase in combustion temperature, an expansion of the combustion zone, which shifts towards the center of the combustion chamber, and a proportional increase in NOx emissions. At a fixed $Q=1.0 \mathrm{~g} / \mathrm{s}$, the leaner combustion could reduce the temperature, and so do NOx emissions. However, the flame shape is changed due to the flame instability, and the combustion zone shifts to the chamber outlet.