## 4 Results and Discussion
### Analysis of Static Pressure and Velocity  
To analyze the influence of different division pier lengths on the pressure and velocity distribution near the wall of the straight outlet conduit, three design schemes and a straight outlet conduit without a division pier were analyzed; the pressure distribution and velocity nephogram as shown in Figures 13 and 14 were then drawn. It can be seen from Figure 13 that the pressure near the wall of the straight outlet conduit increased gradually along the flow direction when the division pier was not set, there was a large high-pressure area in the circular square diffusion section and the straight pipe section of the conduit, and the pressure near the wall of the straight outlet conduit without the division pier was evenly distributed. From scheme 1 to scheme 3, the pressure near the wall in the straight outlet conduit of the division pier with different lengths decreased as a whole, and the pressure increased gradually along the flow direction. The \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Scheme** & **Head Loss (m)** & **Left (Q/Q\({}_{bp}\))** & **Right (Q/Q\({}_{bp}\))** & **Flow Distribution Ratio** \\ \hline
1 & 0.081 & 0.595 & 0.407 & 1.46 \\
2 & 0.078 & 0.592 & 0.408 & 1.45 \\
3 & 0.075 & 0.597 & 0.403 & 1.48 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Flow distribution on both sides of division pier in three schemes. Figure 12: Internal streamline diagram of straight outlet conduit under different design schemes. flow was affected by the division pier, and there was an obvious deviation phenomenon on the left side of the division pier; from scheme 1 to scheme 3, it can be seen that a certain low-pressure area formed on the left side of the division pier, indicating that the near-wall pressure on the left and right sides of the division pier was easily affected by the division pier in the straight outlet conduit, resulting in uneven pressure distribution. From scheme 1 to scheme 3, there was a small high-pressure area near the wall at the starting position of the division pier, which was due to the diversion effect on the flow at the starting position of the division pier, resulting in the disorder of the local streamline; for the flow deviation, there may have been a small range of vortices at the deviant position, resulting in the increase of the pressure near the wall at the starting position of the division pier. However, there was no high-pressure area in the round to square diffusion section and straight pipe section, according to Figure 12; the flow pattern here was good and the vortex could not easily create a high-pressure area. The results show that the pressure near the wall of the straight outlet conduit decreased as a whole and the stress condition of the straight outlet conduit improved, but the division pier with different lengths had no obvious effect on the pressure distribution near the wall of the straight outlet conduit. Figure 13: Pressure nephogram of the near-wall area of the straight outlet conduit. Figure 14 shows the velocity distribution of the straight outlet conduit without a division pier and three design schemes. It can be seen from Figure 14 that the velocity of the straight outlet conduit decreased from the flow direction as a whole due to the effect of the residual circulation and inertia of the flow at the outlet of the guide vane. When there was no division pier, there was a wide low-velocity zone at the bottom of the straight outlet conduit, and the velocity increased gradually from the bottom to the top. From scheme 1 to scheme 3, a large high-speed zone appeared on the left side of the starting position of the division pier due to the influence of the division pier; after adding the division pier, the near-wall velocity at the top and bottom of the division pier decreased. Compared with the case without the division pier, a large low-speed zone appeared at the top of the straight outlet conduit with the division pier, and the low-speed zone at the bottom became larger.