## 3 Results
### Validation  
The flow suffers from more significant acceleration with a narrow passage between vanes, justifying the implementation of the stator despite the losses attached to its usage. Mach number in the passages is, according to Figure 5, about 0.3 on the SS of the vanes at the same time that, on the PS, a detachment bubble can be seen in both ST and RT. On the SS, the blockage effect induced by the impeller is similar to the one that appears in the rotor-less turbine, meaning that the effect of the rotor over the stator reduces its importance when the stator has a broader opening. The lack of rotor favored the appearance of a higher velocity region when compared to the case equipped with the rotor, since the mere presence of the blades provoked losses that reduced velocity after the vane TE. For the closest vane, the channel position studied appears to have the highest acceleration. With this opening, the throat of the channel linked the TE on the PS of one vane with the LE on the SS of the next one. Thus, the acceleration happens toward the throat, consequently at the end of the PS having no detachment at first sight. However, taking a detailed view, as in Figure 6, different phenomena can be seen: a stagnation point perfectly aligned with the vane chord at its LE. In addition, when the flow approached the throat, it gradually accelerated in a smooth way until reaching the throat. Then, the flow suffered a substantial increase in Mach number over the SS of each vane, up to a maximum of about 0.45 Mach for the cases with equal Mach and 0.6 in the \(RT_{Re}\) case. The flow slowed down from half-chord to the TE, which constitutes a throat with the subsequent vane. The contours of the three compared cases are very similar indistinctly from their numerical values, increasing the trend whereby the closer the position, the more independent the stator performance becomes from the rotor. The interaction between rotor and stator decreases, and the ST simulation is more accurate the closer the vane opening is. Figure 5: Mach number distribution at stator midspan. ST and RT; VGT60; 0.5 mm tip height. After observing contours of flow patterns for each vane opening, which allows us to obtain an idea of how valid information from CFD simulations can be, data can be extracted for its processing. Pressure coefficients from different vanes were analyzed and compared, applying Equation (1) to vanes both free of distortion elements in their surroundings (**V7** and **V8**) and vanes that in RT were supposed to be affected by the screws with their analogs in the ST (**V5** and **V6**). \[C_{p}=\frac{p-p_{\infty}}{\frac{1}{2}\cdot\rho_{\infty}\cdot V_{\infty}^{2}} \tag{1}\]  
Data from VGT60, which can be seen in Figure 7 show, in general, a good agreement for the entire chord in both PS and SS. On the one hand, for **V8**, where there were no screws interfering with the vane, \(C_{p}\) distribution on the SS represents the blockage effect, showing a region of higher speed between 60% and 80% of the chord. Mach contours plotted at Figure 5 show the same region. Data between cases collide in the suction peak region in a single line. On the other hand, **V5** has its PS affected by a screw, and this side of the vane does not match that of the ST; however, the whole SS and suction peak are well represented. Right after the screw, the flow is slowed down by the screw (placed at approximately 30% of the chord). When passing next to it, there is a tendency to accelerate the flow due to a nozzle effect between the screw and the vane itself. Finally, in **V6**, which is affected on its SS by the screw, the distortion generated in the flow travels downstream from the scroll, having an impact on its PS, too. However, the primary effect appears only on the first quarter of the vane (on both sides), and after that, the coincidence between RT and ST is nearly perfect. With this data, it can be assured that the studied vane for the ST represented the same effects as the already validated turbine.