Three-dimensional study of the effect of tandem compressor pressure ratio on downstream vortices

.To achieve clean and sustainable energy for power generation and displacement, the engine designers demand a high performance and powerful propulsion. The compressor blades have the task of increasing the loss coefficient and should be considered in the design to prevent the destructive phenomena such as the flow separation. If the reverse pressure on the vane could be engineered in such a way as to prevent the flow separation and control the vortices, a higher loss coefficient would be achieved. A reliable way to achieve this goal is to use a tandem, which is obtained by placing a small secondary blade behind the main blade. In the present numerical analysis, a tandem rotor and stage designed and tested at NASA's Lewis Research Center are studied. The desired geometry is extracted from the mentioned source and a high-quality network with about 896 thousand nodes is applied to it, and then considering the  SST turbulence model, it is analyzed by the CFX commercial software. The rotor and its stage are studied in 5 rounds and therefore 5 different pressure ratios, and the resulting vortices are also subject to investigation and interpretation. Finally, it can be seen that at 2105 revolutions (half of the nominal revolution), both in the rotor and in the tandem compressor stage, the vortices are not fully restrained and occupy a very small area of the pressure diagram in terms of chords, thus demonstrating inappropriate performance. At a pressure ratio of 0.9, we also see a lot of turbulence after the vane, which is not suitable for the operation of the compressor. On the other hand, at 4210 rpm (nominal rpm), the vortices are well restrained and a good reduction in the pressure is observed. It also occupies a lot of space in the graph of pressure by chord. Also, at the pressure ratio of 1.1038, we see a proper formation and control of vortices to reduce the turbulence.