Thermal performance and NOx emission characteristics studies on a premixed methane-ammonia-fueled micro-planar combustor

In the present study, thermal and emission performances of a micro-planar combustor fuelled with methane/ ammonia mixture are numerically investigated. For this, a 3D low-Mach number solver is developed based on OpenFOAM. The effects of equivalence ratios phi, inlet volume flow rates Vi, and ammonia molar fractions in the fuel XNH3 are considered. It is found that the outer wall mean temperature Tw and the non-uniformity RTw vary non-monotonically. There is a contradictory variation between CO and NO emissions with phi. A higher N2O emission occurs under the fuel-rich conditions, while it can be reduced by increasing Vi. Vi plays a critical role in affecting thermal performance. Increasing Vi could lead to an increase of Tw. However, an appropriate Vi should be selected to avoid a higher RTw and a lower radiation efficiency eta r. The variation of NO and CO emission are insensitive to the variation of Vi. The variation of XNH3 almost has negligible effect on Tw but it can lead to a decrease of RTw, especially under fuel-rich conditions. Increasing XNH3 improves eta r at phi = 0.8 and 1.0 while it has little effect at phi = 1.2. The addition of ammonia can reduce the CO2 emission but lead to the increased NO emission. Increasing XNH3 results in the increase of CO emissions at stoichiometric conditions, but the decrease at rich conditions. N2O emission is observed to be increased first and then decreased with increased XNH3. This work provides a preliminary study on the thermal and emission performances of a methane-ammonia fuelled microthermo-photo-voltaic system.

Automated summary

This study numerically investigates the thermal and emission performances of a micro-planar combustor fueled with a methane/ammonia mixture. The results show complex variations in outer wall temperature and non-uniformity with different parameters, as well as contradictory trends in CO and NO emissions with equivalence ratios.