## 4 Results and Discussions
### Laminar Burning Velocity of Binary Fuel Blending  
In the previous Section 4.1, an illustration of the LBV for single-fuel air flames was validated experimentally; this subsection will present the binary fuel blends and the effect of ammonia blends. **For NH\({}_{3}\)/H\({}_{2}\)/air flames**, the LBV is depicted in Figures 3 and 4B as a function of ammonia blend and equivalence ratios for 0%, 20%, and 40% hydrogen blends, respectively. The influence of hydrogen blending on the LBV exhibits a nonlinear dependency, as evidenced by this experiment, and the current experimental results demonstrate a higher  
Figure 2: Summary of laminar burning velocity versus stoichiometric ratios for pure methane and ammonia fuels under atmospheric conditions, compared with those reported in the works of [PERSON] et al. [41], [PERSON] et al. [50], [PERSON] et al. [26], [PERSON] et al. [52], [PERSON] et al. [54], [PERSON] et al. [51], [PERSON] et al. [30], and [PERSON] et al [19]. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Model** & **Species** & **Reactions** & **Fuels** & **Method** & **T (K)** & **P (MPa)** & \(\phi\) \\ \hline Li [33] & 51 & 420 & \(\mathrm{H_{2}/NH_{3}/CH_{4}}\) & Shock tube ignition delay modeling & 1000–2000 & 0.1–5 & 0.5/1/1.2 \\ [PERSON] [21] & 59 & 356 & \(\mathrm{NH_{3}/CH_{4}}\) & Cylindrical constant volume chamber & 298 & 0.1 & 0.8–1.3 \\ [PERSON] [31] & 125 & 1099 & \(\mathrm{H_{2}/NH_{3}}\) & Spherical combustion chamber & 298–473 & 0.1–1 & 0.7–1.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of the selected kinetic models. consistency with literature data [44; 53]. Moreover, the figures show the predicted laminar burning velocities based on three different combustion models. All models underpredict the LBV, with the Li model [33] demonstrating the highest accuracy, and the Okafor model exhibiting the greatest underestimation. [PERSON]'s model [31] considers NH\({}_{2}\) + O = HNO + H, NNH + O\({}_{2}\) = N\({}_{2}\) + HO\({}_{2}\) and NH + OH = HNO + H as very important reactions for predicting LBV, where the NNH radical is a key radical in the ammonia oxidation; the most important reactions are NNH + O\({}_{2}\) = N\({}_{2}\) + HO\({}_{2}\), where thermal dissociation competes with the oxidation reaction NNH = N\({}_{2}\) + H. Moreover, N\({}_{2}\)H\({}_{2}\) has a significant rule, especially on the rich side [31]. It is worth noting that the equivalence ratio value at maximum LBV increases predominantly with hydrogen blending, going from 1.05 for pure ammonia to 1.10 for 40% hydrogen blends. The relationship between hydrogen blending and LBV exhibits a nonlinear dependency, as demonstrated by this experiment. This trend aligns with previous findings that the highest LBV for hydrogen-air flames occurs at \(\phi\) = 1.8. Figure 4: The LBV of dual fuel–air flames versus the equivalence ratio at 0.1 MPa and 298 K, for (**A**) H\({}_{2}\)/CH\({}_{4}\); (**B**) NH\({}_{3}\)/H\({}_{2}\); (**C**) NH\({}_{3}\)/CH\({}_{4}\) blends  
Figure 3: Summary of laminar burning velocity versus stoichiometric ratios for pure methane and ammonia fuels under atmospheric conditions, compared with those reported in the works of [PERSON] et al. [19], [PERSON] et al. [26], [PERSON] et al. [30], and [PERSON] et al. [28]  
It can be observed that none of the models are capable of accurately predicting the measured data. There are noticeable differences between the experimental and computed data, particularly on the rich side of the equivalence ratio. Furthermore, significant discrepancies exist among the computed results obtained from different models, especially with 40% hydrogen addition. It is important to note that these discrepancies between predictions and measurements become more pronounced as the equivalence ratio increases. The Okafor model significantly underpredicts the laminar burning velocity (\(\mathrm{\SI{L}}\)) in most initial conditions, indicating poorer performance compared to the parent model.