Film Cooling Adiabatic Effectiveness for Cylindrical Holes Embedded in Multi Trench Configuration

In this study, computational simulations were made using ANSYS CFX to predict the improvements in film cooling performance with multi trench. Multi-trench configuration consists of two trenches together, one wider trench and the other is narrow trench that extruded from the wider one. Several blowing ratios in the range (0.5, 1, 2 and 3) were investigated. By using the multi trench configuration, the coolant jet impacted the trench wall two times allowing increasing the spreading of coolant laterally in the trench, reducing jet velocity and jet completely covered on the surface. The results indicate that this configuration increased adiabatic effectiveness as blowing ratio increased. The multi trench configuration increased adiabatic effectiveness up to 100% near the hole, 43% at X/D = 40 and 31% at downstream X/D = 137 for blowing ratio of 3 and no observed film blow-off at this blowing ratio. The adiabatic film effectiveness of multi trench configuration outperformed the narrow trench at different blowing ratios