## 3 Results
### Nitrocellulose Experiments and Results  
The 0.3 g nitrocellulose sample was placed on the shelf at a distance of 0.5 m from the sCMOS camera. The nitrocellulose was ignited on-site, and the camera collected a complete flame image. The nitrocellulose burning time was about 2 s, and the collected flame image was brought into the two-color temperature measurement formula. Finally, the temperature image of the nitrocellulose burning flame was obtained, and the temperature images of some typical moments of the flame were recorded in Figure 12. There are three main stages of combustion:  
(1)  
Figure 12a-d of the combustion diffusion stage: the flame gradually spreads and becomes larger from 1.895 cm wide and 4.3 cm high in the initial Figure 12a, with \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & **600 \({}^{\circ}\)C** & **650 \({}^{\circ}\)C** & **700 \({}^{\circ}\)C** & **750 \({}^{\circ}\)C** & **800 \({}^{\circ}\)C** & **850 \({}^{\circ}\)C** & **900 \({}^{\circ}\)C** & **950 \({}^{\circ}\)C** & **1000 \({}^{\circ}\)C** \\ \hline \(U_{k_{R}}\) & 0.92\% & 0.97\% & 0.94\% & 0.85\% & 0.86\% & 0.85\% & 0.83\% & 0.83\% & 0.81\% \\ \(U_{\lambda_{1}\lambda_{2}}\) & 2.13\% & 2.17\% & 2.15\% & 2.09\% & 2.09\% & 2.08\% & 2.07\% & 2.07\% & 2.06\% \\ \(U_{K_{\lambda_{1}\lambda_{2}}}\) & 1.23\% & 1.30\% & 1.26\% & 1.14\% & 1.15\% & 1.13\% & 1.11\% & 1.10\% & 1.08\% \\ \(U_{N_{\mathrm{Cl}_{i}\mathrm{C}_{2}\mathrm{p}_{1}\mathrm{p}_{2}}}\) & 1.29\% & 2.11\% & 0.97\% & 0.40\% & 0.16\% & 0.48\% & 2.27\% & 0.42\% & 0.83\% \\ \(\tilde{U}\) & 2.93\% & 3.43\% & 2.83\% & 2.56\% & 2.55\% & 2.57\% & 3.37\% & 2.52\% & 2.60\% \\ \hline \end{tabular}
\end{table} 
Table 4: Summary of uncertain parameters. Figure 12: Temperature images at different moments of 0.3 g nitrocellulose flame. the flame temperature gradually increasing. The flame in Figure 12d also increases significantly, reaching 3.52 cm wide and 7.67 cm high;
2. Figure 12e,f in the full combustion stage: with the expansion of the contact area between the nitrocellulose flame and oxygen, some alkali metals inside the nitrocellulose are violently burned, the flame has some obvious bright spots, and the temperature is also significantly increased, the width of the flame is more than 3.6 cm, the height is more than 7.7 cm, and the maximum temperature of the flame reaches 993.7 \({}^{\circ}\)C at the time of 1000 ms in Figure 12e;
3. Figure 12g,h of the combustion dissipation stage: with the passage of time, the composition of the energetic material gradually decreases, the temperature of the flame also decreases gradually, and the flame becomes smaller and smaller until it is extinguished. The size of the flame is 1.91 cm wide and 4.9 cm high at 2000 ms. In order to more intuitively see the temperature change process of the nitrocellulose flame, the centerline temperature change curve of the nitrocellulose flame at 1000 ms was plotted, as shown in Figure 13. The temperature change in the centerline shows a gradual increase first, reaching a maximum temperature of 921.8 \({}^{\circ}\)C, and then the temperature began to gradually decline. There is a small increase in the middle, but it soon began to decline continuously. Figure 14 is the maximum temperature change curve of nitrocellulose flame within 0-2000 ms. The \"TC temperature\" in Figure 14 is the flame temperature measured by our two-color method, which is more in line with the characteristics of energetic material combustion, due to the sudden release of energy contained in the ignition moment. It will reach a higher temperature at the beginning; the temperature of nitrocellulose flame at the start reaches 978.4 \({}^{\circ}\)C. The fuel begins to diffuse outward, the temperature drops significantly, and the temperature rises slightly.