Session: 12-08 Advanced numerical methods for film cooling (II)

Submission Number: 177572

Prediction Accuracy Improvement of the Adiabatic Film Effectiveness for Trailing-Edge Cutback Based on Turbulent Viscosity Correction Method 

The trailing edge of turbine blades is susceptible to high-temperature corrosion, making the accurate prediction of its film cooling effectiveness essential for optimal trailing edge design. Currently, the RANS method is commonly used in engineering to predict film cooling effectiveness. However, traditional RANS models tend to underestimate turbulent mixing, leading to significant prediction deviations. Based on the SST model and MIX model, this study improves the prediction accuracy of RANS for the film cooling effectiveness of trailing edge slot film cooling by modifying the turbulent Schmidt number (Sc_t) and the empirical parameter (n). The simulation results are verified through Pressure-Sensitive Paint (PSP) experiments. The results show that modifying only the turbulent Sc_t does not lead to accurate predictions across different blowing ratios. However, setting the n of the MIX model to 1.5 effectively captures the mixing process between the mainstream and the coolant, resulting in a significant improvement in prediction accuracy. For the baseline, the maximum prediction errors in cooling effectiveness under the working conditions of M = 0.25 and 0.50 are less than 5.5% and 3.5%, respectively. Verification using the trailing edge with straight ribs shows that the maximum prediction error under the M = 0.50 condition is less than 5.4%. Additionally, by reproducing two trailing edge models with different configurations, it is found that the maximum deviations between the downstream film cooling effectiveness from simulations and experiments are less than 8.3% and 2.3%, respectively. These results show a significant improvement over those from the unmodified SST model. The conclusions of this study offer a reliable solution for the efficient and accurate numerical prediction of cooling characteristics in trailing edge film cooling.

Presenting Author: Mengjiao Han School of Power and Energy, Northwestern Polytechnical University

Presenting Author Biography: Mengjiao Han is engaged in research on active thermal protection and flow heat transfer analysis of aero-engine hot-section components, with a focus on thermal protection technology for turbine blades in extreme environments, as well as flow-heat analysis of blade trailing edge.

Authors:

Mengjiao Han School of Power and Energy, Northwestern Polytechnical University
Lin Ye School of Power and Energy, Northwestern Polytechnical University
Xuyang Ji School of Power and Energy, Northwestern Polytechnical University
Cunliang Liu School of Power and Energy, Northwestern Polytechnical University
Huiren Zhu School of Power and Energy, Northwestern Polytechnical University
Yingni Zhai Xi'an University of Architecture and Technology