## 3 Results and Discussion
### Particle Distributions with Different Installing Positions of the Deflector  
Figure 18 illustrates the particle distributions at plane 1 with the low deflector installation, the middle deflector installation and the high deflector installation, respectively. To make comparisons, Figure 13, which presents the particle distribution with no deflector installed, is illustrated here as Figure 18a. Tables 2 and 3 give the statistical indices of the particle distributions corresponding to Figure 18. The RSD is used to represent the uniformity of ash particle distributions. Figure 16: Statistical indices for deflectors with different heights: (**a**) the RSDs of velocity, (**b**) the total pressure loss. Figure 17: The distributions of the particles larger than \(8.8\times 10^{-2}\) mm for the deflectors of different heights. Generally, it is indicated that the installation of the triangular deflector cannot substantially improve the distributions of small-sized and medium-sized particles, while it plays a positive role in reducing the accumulation of the large-sized and extra-large-sized particles. Although the performance varies from each other among Figure 18b-d, the accumulated large-sized and extra-large-sized particles \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Case** & \begin{tabular}{c} **Small-Sized** \\ **Particles** \\ \end{tabular} & \begin{tabular}{c} **Medium-Sized** \\ **Particles** \\ \end{tabular} & \
\begin{tabular}{c} **Large-Sized** \\ **Particles** \\ \end{tabular} &
\begin{tabular}{c} **Extra-Large-Sized** \\ **Particles** \\ \end{tabular} \\ \hline No deflector & 16.97\% & 40.94\% & 75.25\% & 117.29\% \\ Low deflector & 17.39\% & 43.60\% & 61.73\% & 66.12\% \\ Middle deflector & 17.05\% & 48.59\% & 68.96\% & 67.38\% \\ Installation & 13.73\% & 44.76\% & 76.67\% & 78.98\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The RSDs of distributions for small-sized, medium-sized, large-sized and extra-large-sized particles at plane 1 with different installing positions of the triangular deflector. Figure 18: The distributions of the four classes of particles at plane 1 with different installing positions of the triangular deflector: (**a**) no deflector installed, (**b**) the low deflector installation, (**c**) the middle deflector installation, and (**d**) the high deflector installation. are dispersed and the corresponding maximum percentage decreases. The installation of the triangular deflector may not only disperse particles itself but also reduce the momentum of the particles. When passing the turnings in the downstream side, the particles larger than \(8.8\times 10^{-2}\) mm possess fewer inertia and are unable to accumulate easily in the area near the central line of plane 1. As shown in Tables 2 and 3, the low deflector installation gives the best performance on reducing the accumulation of large-sized and extra-large-sized particles. Compared with Figure 18a, which shows the particle distribution without the deflector, the maximum percentages of the accumulated large-sized and extra-large-sized particles decrease from 26.73% to 21.70% and from 39.84% to 20.59%, respectively, which is better than the middle and high deflector installations. Besides, the RSDs of the large-sized and extra-large-sized particles with the low deflector installation are 61.73% and 66.12%, which is the smallest among the four cases. Likewise, investigations are also conducted on the particle distributions at plane 2. Figure 19 shows the corresponding distributions with different installing configurations of the deflector. It is indicated that the installation of the deflector has a notable performance on reducing the particle accumulation near the right-side wall. However, the ash particles cannot be dispersed effectively to the left side of plane 2. This is mainly due to the limitation of the height of the triangular deflector. Enlarging the deflector will lead to the increase of the total pressure loss.