# Simulation of the Influence of Wing Angle Blades on the Performance of Counter-Rotating Axial Fan
## 6 Conclusions  
The following conclusions can be drawn from this study:  
1. The pressure distribution on the pressure surface of the secondary blade of the optimal wing angle blade fan is stronger than that of the prototype blade. Additionally, the maximum pressures at blade heights of 25%, 50%, and 75% are increased by 2.3%, 9.3%, and 8.1%, respectively, compared with the prototype blades at the same blade height.
2. The angle blade can effectively reduce the generation of shedding vortices at the trailing edge of the blade, and reduce the strength of the shedding vortex, so that the entropy production of the optimal angle blade fan in the orthogonal experiment is reduced by 1.55% compared with the prototype fan.
3. Compared with the prototype fan, the total pressure and efficiency of the optimal wing angle blade fan are increased by 7.24% and 1.76% at the rated flow, and the total pressure of the blade is reduced by 1.55% compared with the prototype fan.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Prototype Fan**} & \multicolumn{2}{c}{**Wing Angle Blade Fan**} \\
**Blade Stage** & \begin{tabular}{c} **Minimum** \\ **Equivalent** \\ **Stress/MPa** \\ \end{tabular} & \begin{tabular}{c} **Maximum** \\ **Equivalent** \\ **Stress/MPa** \\ \end{tabular} & \
\begin{tabular}{c} **Minimum** \\ **Equivalent** \\ **Stress/MPa** \\ \end{tabular} &
\begin{tabular}{c} **Maximum** \\ **Equivalent** \\ **Stress/MPa** \\ \end{tabular} \\ \hline First-stage blade & 0.0008 & 61.8577 & 0.0011 & 53.2365 \\ Second-stage blade & 0.0048 & 40.0064 & 0.0046 & 40.4835 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Equivalent stress of blade.  
Figure 14: Deformation distribution of wing angle blades and prototype blades. (**a**) First-stage blade deformation distribution; and (**b**) second-stage blade deformation distribution.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Blade Stage** & \
\begin{tabular}{c} **Maximum Deformation/mm** \\ **Prototype Fan** \\ \end{tabular} &
\begin{tabular}{c} **Wing Angle Blade Fan** \\ \end{tabular} \\ \hline First-stage blade & 0.0969 & 0.0463 \\ Second-stage blade & 0.0624 & 0.0411 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Maximum deformation of the blade.  
pressure and efficiency are increased by 11.32% and 3.88% on average under the full flow condition.
4. In the orthogonal experiment, the maximum sound power levels of the first and second blade trailing edge regions of the optimal wing angle blade fan were reduced by 0.17% and 1.62%, respectively, compared with the prototype fan.  
Conceptualization, G.G., Z.K. and Q.Y.; methodology, X.Z.; software, X.Z.; validation, G.G., Z.K. and X.Z.; formal analysis, X.Z.; investigation, G.G., X.Z.; resources, Z.K.; data curation, G.G., X.Z.; writing--original draft preparation, G.G., X.Z., X.G.; writing--review and editing, G.G., X.G.; visualization, G.G., X.Z.; supervision, Z.K., Q.Y.; project administration, Z.K., Q.Y. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
This studies do not involve humans or animals.  
No involving humans.  
Not applicable.  
The authors gratefully acknowledge the financial support of Nature fund of Chongqing Science and Technology Bureau (No. cstc2020 jcyj-msxmX0793) and the Research plan projectof Chongqing Education Committee (No. KJQN202003402).  
The authors declare no conflict of interest.