Flat Plate and Turbine Vane Film-Cooling Performance with Laid-Back Fan-Shaped Holes

Abstract

Shaped holes are considered as an effective solution to enhance gas turbine film-cooling performance, as they allow to increase the coolant mass-flux, while limiting the detrimental lift-off phenomena. A great amount of work has been carried out in past years on basic flat plate configurations while a reduced number of experimental works deals with a quantitative assessment of the influence of curvature and vane pressure gradient. In the present work PSP (Pressure Sensitive Paint) technique is used to detail the adiabatic effectiveness generated by axial shaped holes with high value of Area Ratio close to 7, in three different configurations with the same 1:1 scale: first of all, a flat plate configuration is examined; after that, the film-cooled pressure and suction sides of a turbine vane model are investigated. Tests were performed varying the blowing ratio and imposing a density ratio of 2.5. The experimental results are finally compared to the predictions of two different correlations, developed for flat plate configurations.

Uncertainty Quantification of Film Cooling Performance of an Industrial Gas Turbine Vane

“…The objective of this activity was to carry out an uncertainty quantification analysis on an additive manufactured gas turbine vane. Initially, results were validated with the experimental ones provided by Bacci et al [2]. This part proved how a RANS simulation with k-w SST turbulence model with a full domain accurately represents the experimental outcomes, except for the last row with a 10% overestimation in terms of η ad .…”

“…The considered test article consists of a film-cooled prismatic vane airfoil, obtained through the extrusion of the midspan profile of a typical second stage vane. In a previous work [2], this airfoil was installed in a single vane, two-passages, linear cascade rig in order to experimentally characterize its behavior in terms of adiabatic film effectiveness. The cascade rig geometry (i.e., inlet duct, sidewalls, and outlet section) was designed through a CFD optimization process in order to prescribe representative conditions, in terms of Mach and Reynolds numbers as well as of flow acceleration and pressure gradients, within the two-passage configuration.…”

“…A section of the test rig, with a focus on the test section, is reported in Figure 1. A more detailed description of the test apparatus can be found in [1,2].…”

“…A section of the test rig, with a focus on the test section, is reported in Figure 1. A more detailed description of the test apparatus can be found in [1,2]. The film cooling scheme adopted in the tested airfoil is characterized by three rows of axial laidback fan-shaped holes: two of them are located close to the leading edge (LE), while the third is far downstream and close to the trailing edge (TE).…”

“…This work is based on the test case studied and analyzed by Bacci et al [1]. The adiabatic film effectiveness (η ad ) was experimentally characterized in a previous campaign [2]. As demonstrated by previous works [3][4][5], the CFD analysis is a must-have tool for the design and the optimization phases of film cooled vanes and blades.…”