## 3 Results and Analysis
### Analysis of Blade Performance and Model Establishment  
To analyze the performance influence of two-position deviations, the deviations in the \(-0.1\) and \(-0.3\) normalized position were first studied. The minimum profile loss coefficient, the positive incidence range and the negative incidence range were solved on the separated condition and coexisting condition. Figure 3a shows the change of profile loss on the separated condition. It can be seen that when the geometric deviation is in \(-0.1\) position, the profile loss increases more than when it is in the \(-0.3\) position. This result is consistent with the research conclusions on the aerodynamically sensitive area of the compressor blade [15]. While the blade loss is slightly reduced when the deviation is in \(-0.3\) position, this is related to the actual blade profile design. Figure 3b shows the comparison of profile loss between the sum of the separated condition and the coexisting condition. It can be seen that the two results have slight differences. The profile loss of the coexisting condition is higher than the sum of the separated condition. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Local/average spacing ratios in leading edge & 0.1 \\ Local/average spacing ratios in trailing edge & 0.9 \\ Inlet and outlet grid type & H-type \\ Number of inlet points & 50 \\ Number of outlet points & 30 \\ Number of streamlines & 20 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: MISES grid parameters. Figure 3: Analysis of the minimum profile loss coefficient. (**a**) Profile loss of the separated condition. (**b**) Comparison of the profile loss between the sum of the separated condition and the coexisting condition. Figure 4 is a comparison of incidence range between the sum of the separated condition and the coexisting condition. In both figures, it can be clearly observed that there will be an obvious error in estimating the incidence range of the coexisting condition by simply adding the influences of the separated condition. From Figure 4, it can be seen that the slope of the solid line is smaller than the slope of the dotted line, which means the influence of the deviation in the \(-0.3\) position is weakened when there is a deviation in the \(-0.1\) position. Furthermore, this weakened effect becomes obvious when the deviation height in \(-0.1\) position increases. From Figure 4, it can be observed that the influence of the deviation in the \(-0.3\) position is enhanced when there is a deviation in the \(-0.1\) position. In order to analyze the reasons for this phenomenon, Figure 5 shows the development of the boundary layer when the heights of the deviation are both \(0.1\)mm. The reason of selecting this deviation height for analysis is to observe the obvious changes in the boundary layer. It can be seen from Figure 5, for the suction surface, the momentum thickness of the boundary layer under the positive incidence limit is much thicker than the momentum thickness under the negative incidence limit. Simultaneously, the transition position changed a lot in two different incidence limit states. The transition position of the boundary layer under the positive incidence limit is about \(0.07\). However, it changes to \(0.17\) under the negative incidence limit, which is a position between the two deviations. Figure 4: Analysis of the incidence range. (**a**) Comparison of the positive incidence range between the sum of the separated condition and the coexisting condition. (**b**) Comparison of the negative incidence range between the sum of the separated condition and the coexisting condition. Figure 5: Development of the boundary layer on the suction surface. (**a**) Analysis of the boundary layer when the incidence is under the positive incidence limit. (**b**) Analysis of the boundary layer when the incidence is under the negative incidence limit.