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Three different kinds of coolant chamber configuration for film cooling are proposed to develop the swirling coolant flow at blowing ratios ranging from 0.5 to 2.0. The results show that the difference of film cooling effectiveness for three kinds of coolant chamber configuration is little at low blowing ratio, but the advantage of swirling film cooling becomes obviously with the increase of blowing ratio. When the blowing ratio is 2.0, the jet momentum of original coolant chamber configuration is large and uniform, which leads to the lowest cooling effectiveness due to the formation of a strong kidney vortex. The first coolant chamber configuration has a low jet momentum region at upstream of the film hole, the coolant in this region interacts with high temperature mainstream and bypasses the large jet momentum coolant to attach cooling surface at downstream. The second coolant chamber configuration is sprayed with the structure of unidirectional vortex, which forms a vortex pressing on other vortex, making the coolant in pressed vortex attach surface better, producing the best coverage and the higher film cooling effectiveness. [ABSTRACT FROM AUTHOR]

The aerodynamic, heat transfer and film cooling characteristics of three tip configurations (including pressure-side partial squealer tip, suction-side partial squealer tip and cavity squealers tip) with cooling are evaluated on transonic turbine, and the effect of the jet and shroud motion are talked. The flow and heat transfer mechanisms of three cooled tip configurations are analyzed. Results show that both the jet and shroud motion alter the tip gap flow, which is found to have a different impact on the aerothermal and film cooling performances of three tip configurations. The addition of cooling significantly increases the overall heat transfer coefficient of the SS tip, but has a relatively small impact on that of the PS tip and Squealers tip. As a result, the total h ¯ of SS cooled tip is even increased by 9.0% compared to Squealers cooled tip. The shroud motion increases the film cooling effectiveness of PS cooled tip and Squealers cooled tip, but reduces that of SS cooled tip. Under the moving shroud condition, Squealers cooled tip have significant advantages in aerodynamic, heat transfer and film cooling performances compared to the other two cooled tip structures. [ABSTRACT FROM AUTHOR]

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. • The interaction between the swirling coolant and the mainstream restructures the vortex structure and restrains the passage vortex. • The swirling coolant has better ability to adhere to the wall and stability, making it difficult for swirling coolant lifted off the wall. • Swirling cooling scheme enhances endwall overall cooling performance. • The pressure surface corner region where is difficult to cool obtains good coolant coverage effect. [ABSTRACT FROM AUTHOR]