## 4 Results and Discussion
### Experimental Results and Analysis  
The results of the orthogonal experiment (schemes 1-9) are shown in Table 6. A range analysis was utilized to analyze the experimental results. Among the two main indicators examined, the higher the sensible heat recovery, the better. And the overall pressure drop should be appropriately small. The range analysis of the experimental results is shown in Table 7. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Scheme**} & \multicolumn{4}{c}{**Factors**} & \multicolumn{2}{c}{**Results**} \\  & \(\mathbf{w}\) **(m)** & \(\mathbf{l}\) **(m)** & \(\mathbf{\beta}\) (\({}^{\circ}\))** & \(\mathbf{\alpha}\) (\({}^{\circ}\))** & **Sensible Heat Recovery (J)** & **Pressure Drop (Pa)** \\ \hline
1 & 1 (1.0) & 1 (0.3) & 1 (14) & 1 (13) & 505,706 & 8530 \\
2 & 1 & 2 (0.5) & 2 (16) & 2 (15) & 504,251 & 8164 \\
3 & 1 & 3 (0.7) & 3 (18) & 3 (17) & 504,318 & 8232 \\
4 & 2 (1.1) & 1 & 2 & 3 & 501,501 & 6663 \\
5 & 2 & 2 & 3 & 1 & 503,068 & 7046 \\
6 & 2 & 3 & 1 & 2 & 503,463 & 7934 \\
7 & 3 (1.2) & 1 & 3 & 2 & 499,240 & 6427 \\
8 & 3 & 2 & 1 & 3 & 500,886 & 6996 \\
9 & 3 & 3 & 2 & 1 & 501,029 & 7107 \\ \hline \end{tabular}
\end{table} 
Table 6: Orthogonal experimental results. According to the results of the range analysis, the influence order of the Venturi furnace structure parameters on the sensible heat recovery and the gas pressure drop of the sinter was different. For the sensible heat recovery, the width w of the vertical part had the greatest influence, followed by the contraction angle \(\beta\) and the expansion angle \(\alpha\), and their effects were similar. The length \(l\) of the vertical part had the least influence; for the pressure drop, the structural parameter with the greatest influence was still \(w\). The next were \(\beta\) and \(l\), and the effects of the two were similar. The influence of \(\alpha\) was the smallest. The trend in the sensible heat recovery and pressure drop was consistent, that is, the higher the sensible heat recovery, the greater the gas pressure drop, but there was a difference in the magnitude of the change between the two. The influence of individual structural parameters is shown in Figure 5. As shown in Figure 5a, when the vertical section width \(w\) was reduced, the sensible heat recovery increased approximately uniformly, while the pressure drop first increased slightly and then increased significantly. Therefore, the value of w can be set to 1.1 m to achieve a higher sensible heat recovery while avoiding excessive increases in the pressure drop. The contraction angle \(\beta\) was the second most important parameter affecting the sensible heat recovery and pressure drop, as shown in Figure 5b. When \(\beta\) decreased, both the sensible heat recovery and the pressure drop first increased slightly and then increased significantly. Therefore, the value of \(\beta\) can be set to \(16^{\circ}\). The expansion angle \(\alpha\) had a greater impact on the sensible heat recovery than on the pressure drop. As shown in Figure 5c, when \(\alpha\) was reduced to \(13^{\circ}\), the sensible heat recovery increased significantly. Therefore, the value of \(\alpha\) can be set to \(13^{\circ}\). The influence of the vertical section length \(l\) on the pressure drop exceeded that on the sensible heat recovery. As shown in Figure 5d, when \(l\) exceeded 0.5 m, the increase in the pressure drop became larger, and the increase in the sensible heat recovery became smaller. Therefore, the value of \(l\) was set to 0.5 m. In summary, the appropriate combination of structural parameters for the Venturi furnace is \(w\) = 1.1 m, \(\beta\) = \(16^{\circ}\), \(\alpha\) = \(13^{\circ}\), and \(l\) = 0.5 m.