Fuel | 2021
Thermal performance and NOx emission characteristics studies on a premixed methane-ammonia-fueled micro-planar combustor
Abstract
Abstract 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 Φ, inlet volume flow rates Vi, and ammonia molar fractions in the fuel XNH3 are considered. It is found that the outer wall mean temperature T - w and the non-uniformity R - Tw vary non-monotonically. There is a contradictory variation between CO and NO emissions with Φ. 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 T - w . However, an appropriate Vi should be selected to avoid a higher R - Tw and a lower radiation efficiency η r . The variation of NO and CO emission are insensitive to the variation of Vi. The variation of XNH3 almost has negligible effect on T - w but it can lead to a decrease of R - Tw , especially under fuel-rich conditions. Increasing XNH3 improves η r at Φ\xa0=\xa00.8 and 1.0 while it has little effect at Φ\xa0=\xa01.2. 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 micro-thermo-photo-voltaic system.