Research on the effect of the swirling coolant within endwall passage on film cooling/heat transfer and aerodynamic losses

In the turbine passage, the secondary flow makes the film cooling jets driven from the pressure side to the suction side, resulting in the corner region of the pressure surface is difficult to cool. In this paper, end-wall film cooling performance and aerothermal performance with the three cases, which include the cylindrical cooling scheme, the swirling cooling scheme and the compound cooling scheme, at different axial positions of the turbine passage are studied respectively. Results show that significant improving the cooling performance for the swirling case at corner region of pressure surface is found. Furthermore, its overall adiabatic averaged cooling effectiveness at different axial positions are all increased. Compared with the compound and cylindrical cases, the swirling cooling effectiveness of the first row is increased by 77.4% and 63%, respectively, at M = 2.2. The physical mechanism of the improvement end-wall cooling performance is that the pair anti-vortex produced by the swirling coolant are twisted and squeezed each other, which makes the coolant injections attached to the wall and achieves a larger coolant coverage in lateral direction. Although the swirling cooling scheme increases the heat transfer of the endwall, it still has the best overall endwall cooling performance.

Automated summary

Research shows that using a swirling cooling scheme can significantly improve the cooling effectiveness in the corner region of the pressure surface in the turbine passage, and overall cooling effectiveness at different axial positions. The swirling cooling can achieve a better cooling performance by generating a pair of anti-vortices.