Combustion performances of premixed ammonia/hydrogen/air laminar and swirling flames for a wide range of equivalence ratios

Abstract

Ammonia, a carbon-free source of hydrogen has recently gained considerable attention as energy solution towards a green future. Previous works have shown that adding 30VOL.% hydrogen with ammonia can eradicate the drawbacks of pure ammonia combustion but no study in the literature has investigated this blend across a wide range of equivalence ratios. The present work investigates 70/30VOL.% NH3/H2 blend from 0.55 ≤ Φ ≤ 1.4 for both premixed laminar spherically expanding flames and turbulent swirling flames at atmospheric conditions. A detailed chemistry analysis has been conducted in Ansys CHEMKIN-PRO platform using a chemical reactor network (CRN) model to simulate the swirling turbulent flames. NO and NO2 emissions have followed similar bell-shaped trends, peaking at around Φ = 0.8, while N2O emission rises at lean conditions (Φ ≤ 0.7). The results indicate that Φ = 1.2 is the optimum equivalence ratio with reduced NOX emissions and some ammonia slip.