# Experimental and Numerical Research on End-Wall Flow Mechanism of High-Loading Tandem Stators
## 6 Conclusions  
The loss distribution of tandem stators and the end-wall flow mechanism were investigated by experimental and numerical methods. The results of the study could be summarized as follows:  
1. In the context of tandem stator performance, the evolution of losses exhibited distinct characteristics: Although the loss variation pattern of the FB was similar to that of a conventional stator, its corner region was affected by the RB, leading to slight differences in the end-wall regions. The variation pattern of RB loss was significantly different from that of a conventional stator; specifically, the loss in the mid-span region of the blade gradually increased, reaching a proportion exceeding 60% at NS. Meanwhile, the total pressure loss and its proportion in the RB root region gradually decreased.
2. The effect of the RB on the corner separation of the FB in tandem stators involves two contrasting mechanisms. On one hand, the acceleration of the flow in the gap between the FB and RB reduced the reverse pressure gradient on the suction surface of the FB, thereby mitigating boundary layer separation and reducing associated losses. On the other hand, the presence of the RB caused a stagnation effect that increased the load on the FB, which in turn exacerbated corner separation and increased losses in the corner region. Ultimately, these opposing effects contributed to an overall increase in losses in the end-wall region, where corner separation played a dominant role.
3. The low-energy fluid generated by corner separation in the FB was more susceptible to migrating towards the mid-span of the blade due to the circumferential pressure difference within the RB channel. This flow dynamic ultimately led to an accumulation of low-energy fluid at the mid-span region, causing significant losses in this area. Moreover, the substantial circumferential pressure difference at the front of the RB, combined with the low-energy fluid in the boundary layer at the RB inlet, predisposed the RB to forming corner separations. However, as the flow coefficient decreased, the  
Figure 25: Contours of dimensionless axial velocity at the exit of the tandem FB and RB at corner stall condition.  
increasing wake and corner separation from the FB created more blockage in the RB's path, which gradually reduced the load on the RB. Consequently, despite the initial tendency for corner separation, the RB's corner separation did not deteriorate further. 4. The corner stall occurred in the FB of the tandem stator, and the stalled cluster caused significant blockage within the RB channel due to the reverse pressure gradient and circumferential pressure difference on the RB. This phenomenon resulted in higher losses in the corner region compared to a conventional blade, underscoring the need for greater attention to these factors in the design of tandem stators.  
Writing--original draft preparation, C.Z.; funding acquisition, B.L.; writing--review and editing, M.Q. and Y.H.; investigation, Z.J. participated in the initial manuscript review. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (No. 52306057).  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed at the corresponding author.  
The authors declare no conflicts of interest.  
The original contributions presented in this study are included in the article. Further inquiries can be directed at the corresponding author.  
The authors