• Citer

Exploiting three-way mixing in a reverse flow combustor to suppress NOx and CO in non-premixed hydrogen-enriched methane flames

par Salah, Mohamed salah eddine;Kamal, Muhammad Mustafa ;Tarabet, Lyes;Parente, Alessandro
Référence Applied thermal engineering, 298, page (130761)
Publication Publié, 2026-04-18

Article révisé par les pairs

• Accès en ligne
• Détails
• Contenu
• Statistiques

Résumé :

Hydrogen enrichment of methane improves lean operability but can shift the NO–CO trade-off in ultra-lean non-premixed flames. High-H2 operation in stagnation-point reverse-flow (SPRF) configurations near blow-off is insufficiently characterized. This study examines how H2 fraction and inlet-air annulus geometry affect stability, chemiluminescence and emissions, and assesses OH* as a NO indicator. Experiments used air preheated to 500–900 K at ϕ=0.3–0.5 with 0–80% H2 (vol.), combining chemiluminescence imaging and exhaust-gas analysis and comparing two inlet-air annulus diameters. Increasing H2 suppresses CO, while NO increases, with stronger sensitivity at higher air preheat. On the other hand, low-H2 cases are found to be unstable at the lowest preheat. Two stable flame states (attached/detached) occur over a wide composition range, extending to pure hydrogen mixtures. A calibrated linear OH*–NO model predicts NO with R2 ≈ 0.925. Reducing the inlet-air annulus diameter increases air velocity and mixing, contracts the reaction zone and shifts operation toward lower CO and NO at low preheat. These findings support passive monitoring for practical combustor tuning.