Numerical investigation of geometric design effect on micromix hydrogen combustion

This paper addresses the optimisation of the hydrogen micromix combustor design. Building on the existing micromix concept, the micromix combustor geometry was modified to enhance the NOX reduction capability. The internal geometric parameters, such as mixing distance and air gate height, were optimised and numerically studied. The results convincingly demonstrated a significant influence of geometric modifications on combustion performance. NOX emissions produced during combustion were successfully reduced by changing the internal geometry of the micromix combustor, and a clear relationship between NOX emission variation and geometric parameter changes was concluded. The results showed that increasing the mixing distance improves the air/fuel mixing, contributing to lower NOX production, while a lower air gate design reduces the temperature along the chamber and resulted in the NOX reduction.