Combustion characteristics of NH3/H2/N2/air adopting the H2-assisted turbulent jet ignition

Adopting ammonia (NH3) is considered a viable way to reduce carbon emissions. The combustion of NH3/air can be enhanced through the fuel dissociation strategy and the use of turbulent jet ignition (TJI). This study investigated the combustion of partially dissociated NH3 ignited by active TJI. It can be found that the hydrogen (H2) pre-chamber effectively enhances the combustion of partially dissociated NH3, and the appropriate rich prechamber equivalence ratio is beneficial for the main chamber ignition. The lean main chamber mixtures realize the flame ignition mechanism and show a lower ignition delay. The increase in dissociation ratio enhances the tolerance of ignition to turbulence and leads to flame ignition mechanism. The increase in dissociation ratio also enhances the inhibiting effect of additional nitrogen (N2) on combustion, but the ignition mechanism and flame shape are not sensitive to the additional N2.