Experimental investigation on ammonia combustion behavior in a spark-ignition engine by means of laminar and turbulent expanding flames

Ammonia combustion appears as a meaningful way to retrieve stored amounts of excess variable renewable energy, and the spark-ignition (SI) engine has been proposed practical conversion system. The present work aims at elucidating characteristics ammonia blends in engine-relevant turbulent conditions. To that end, laminar flame experiments were conducted constant-volume vessel conditions 445 K 0.54 MPa assess behavior ammonia/hydrogen/air, ammonia/methane/air methane/hydrogen/air mixtures observed an all-metal single-cylinder SI engine. Results show respective accelerating or decelerating effects hydrogen methane enrichment could not be sufficiently explained by measured burning velocities mixtures. Since latter are very low, studied regimes boundary between thin broken reaction zones regimes, thus strongly influenced flame-turbulence interactions. quantification response turbulence shows much higher for blends, than methane-based fuels. aforementioned opposite with on velocity during correlated thermochemical properties reactants sensitivity stretch. may explain unexpected bending effect turbulent-to-laminar ratio when increasing fraction ammonia/hydrogen blend. Nevertheless, good correlation was found Karlovitz Damköhler numbers, suggests engines described following usual models. This encourages further investigations optimization systems, means dedicated numerical simulations.