Numerical Analysis of Multi-zone Trench Cooling on an Adiabatic Flat Plate for Gas Turbine Application

A 3D numerical analysis on an adiabatic flat plate for multi-zone trench cooling is performed in the current investigation. A super-long-diamond (SLD) arrangement with continuous (20 rows) and a three-zone 5×5×5 (15 rows) trench hole configuration is used with 30° forward coolant injection at blowing ratio (BR) 1.0. A velocity profile of 1/7 power law is set at the mainstream inlet for the present study. The SLD arrangement with a three-zone 5×5×5 trench hole configuration has been studied, and a comparison between continuous (20 rows) and a three-zone 5×5×5 (15 rows) trench hole configuration has been made. Results show that the super-long-diamond arrangement with a three-zone 5×5×5 (15 rows) trench holes provides almost similar cooling as continuous (20 rows), which reduces the number of effusion holes and the coolant mass requirement. The effectiveness of lateral film cooling is determined downstream after analysing the row-to-row interaction between coolant jets and mainstream. According to the dimensionless temperature contours overlaid with streamlines, a three-zone 5×5×5 (15 rows) trench hole configuration with forward injection produces a developed effusion layer due to counter-rotating vortex pairs, which helps in proper coolant jet mixing into the mainstream and boosts the effectiveness of film cooling in both the longitudinal and laterally directions.