Effect of Combustion Chamber Outlet Swirling Flow on Flow Pattern, Heat Transfer and Cooling Characteristics of Turbine Vane Endwall

The strong swirling flow and nonuniform temperature at the outlet of lean oil premixed combustion chamber transfer downstream, which directly affects the aerodynamic performance of the vane endwall of downstream turbine, and then changes the endwall heat transfer and film cooling characteristics. The combustion chamber is designed with typical outlet velocity and temperature characteristics. Comparing with the experimental data, we have verified that the swirling flow and temperature distribution of designed combustion chamber outlet is typical. In this paper, we studied the influence of combustion chamber outlet swirling flow on the flow pattern, heat transfer and film cooling characteristics of the turbine vane endwall by numerical solution of 3D Reynolds-averaged Navier-Stokes (RANS) equation and shear stress transport turbulence model (SST k-ω). The flow field pattern, heat transfer and film cooling characteristics of the turbine vane endwall at 5 relative positions along the pitch between the center of combustion chamber outlet swirling flow and the turbine vane are compared and analyzed. The result shows that when the center of combustion chamber outlet swirling flow is facing the vane 1, the lateral movement of the pressure side leg of the horseshoe vortex is weakened, and the heat transfer at endwall exacerbates due to downstream movement of stagnation point; the coolant at the third row of film hole is taken away from the endwall, so the heat insulation effectiveness of air film decreases. When the swirling flow center is facing the vane 2, the pressure side leg of the horseshoe vortex envelopes the coolant at the second row of film hole and impacts suction surface, which improves the secondary cooling effect while the average film cooling effectiveness at the endwall surface increases (the maximum value is 0.148, and the surface averaged net heat flux reduction is 0.055 5). This study reveals the influence mechanism of the combustion chamber outlet swirling flow on the flow field pattern, heat transfer and film cooling characteristics at the endwall of the downstream turbine vane, which provides some reference for the layout design of endwall film cooling. © 2022, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.