No abstract

Variations in methane–ammonia blends with hydrogen enrichment can modify premixed flame behavior and play a crucial role in achieving ultra-low carbon emissions and sustainable energy consumption. Current combustion units may co-fire ammonia/methane/hydrogen, necessitating further investigation into flame characteristics to understand the behavior of multi-component fuels. This research aims to explore the potential of replacing natural gas with ammonia while making only minor adjustments to equipment and processes. The laminar burning velocity (LBV) of binary blends, such as ammonia–methane, ammonia–hydrogen, and hydrogen–methane–air mixtures, was investigated at an equivalence ratio of 0.8–1.2, within a constant volume combustion chamber at a pressure of 0.1 MPa and temperature of 298 K. Additionally, tertiary fuels were examined with varying hydrogen blending ratios ranging from 0% to 40%. The results show that the laminar burning velocity (LBV) increases as the hydrogen fraction increases for all mixtures, while methane increases the LBV during blending with ammonia. Hydrogen-ammonia blends are the most effective mixture for increasing LBV non-linearly. Enhancement parameters demonstrate the effect of ternary fuel, which behaves similarly to equivalent methane in terms of adiabatic flame temperature and LBV achieved at 40% hydrogen. Experimental data for neat and binary mixtures were validated by different kinetics models, which also showed good consistency. The ternary fuel mixtures were also validated with these models. The Li model may qualitatively predict well for ammonia-dominated fuel. The Shrestha model may overestimate results on the rich side due to the incomplete N2Hisub-mechanism, while lean and stoichiometric conditions have better predictions. The Okafor model is always overestimated.

The response surface methodology - central composite design matrix (RSM-CCD) is applied to make experiment design and response optimization for CIE engine fulled by different methanol-biodiesel-diesel blending ratios. The 5% biodiesel has enhanced methanol-diesel miscibility by about twelve folds. A full factorial design is employed to build the experimental tests of the performance and exhaust emissions for CIE run by methanol/biodiesel/diesel fuel. The statistical tests are used to check the significance of models by p-value test, adeq. Precision test, Predicted R2, and adjusted R2. With a maximum error of 6%, models of the BTE, CO, UHC, CO2, and NOX are showed a good agreement between predicted and experimental results. The optimization indicated that engine load is a master input factor affecting the responses.