Experimental study on the combustion of NH3/H2/air based on the passive turbulent jet ignition.

• Combustion characteristics of NH 3 /H 2 /air with SI and TJI methods were compared. • Effect of fuel composition and equivalence ratio was evaluated under TJI conditions. • Different ignition mechanisms of NH 3 /H 2 /air were found. • Effect of orifice number on ignition and combustion characteristics was evaluated. The mixture of ammonia (NH 3) and hydrogen (H 2) is the potential alternative fuel for internal combustion engines (ICEs). The turbulent jet ignition (TJI) system can provide high ignition energy and turbulent disturbance to promote the combustion of the mixture for NH 3 /H 2 ICEs. Therefore, the combustion characteristics of NH 3 /H 2 /air under passive TJI conditions were experimentally studied in the present study. The experiment was conducted in a constant volume combustion bomb, and the effect of fuel composition and equivalence ratio was investigated. The experimental results show that compared to spark ignition, the combustion of NH 3 /H 2 can be effectively improved by using TJI, especially under high NH 3 fraction conditions. The addition of H 2 has a significant positive effect on the ignition and combustion performance. With the addition of H 2 , the ignition delay and combustion duration decrease evidently. And the H 2 addition is beneficial for improving the ignition mechanism and achieving flame ignition. In addition, poor ignition performance may occur under rich conditions due to the fluid-dynamic quenching of the jet. However, the high flame propagation rate on the rich side still leads to lower combustion duration. Moreover, increasing the orifices number appropriately can enhance the ignition and combustion performance. The jet strength is weakened by the increased total orifice area and the ignition of NH 3 /H 2 can be improved. [ABSTRACT FROM AUTHOR]