Session: 12-08 Effects of film cooling geometry on cooling performance (I)

Paper Number: 127255

127255 - Numerical Study on the Console Hole Film Cooling Performance With Varied Hole Inlet Shape 

The shaped holes are widely used to improve the film cooling performance in gas turbine thermal protection. Among them, the console hole is a well performed shaped hole, but its cooling effectiveness can be severely deteriorated near the centerline at a small incident degree. In this paper, the geometry of the console hole, particularly the inlet shape, was adjusted using numerical simulation methods to improve the cooling performance of the console hole. Different console holes with varying inlet widths but the same inlet area were tested on a flat plate inclined at 30 degrees, with blowing ratios ranging from 0.5 to 2.0. The mainstream Reynolds number was set to 10000 based on the film hole inlet diameter, and the density ratio was 1.5. The RANS equations were closed by the RNG k-ε model and the structured grid consisting of 7.64 million cells was adopted to provide a relatively accurate predictive result. It is found that kidney vortices near the centerline of the classical console holes are responsible for the severe deterioration in cooling performance, resulting in the loss of coolant protection in the downstream centerline region and exhibiting trace bifurcation. These kidney vortices mainly originate from flow separation generated when coolant flows from the plenum into the hole. Widening the inlet width of the console hole increases the spacing between kidney vortices within the hole. This reduces the mutual induction between the vortices and suppresses their development within the hole, ultimately eliminating the kidney-shaped vortices along the downstream centerline. In the flow field of the console hole with a larger inlet width, the predominant structures are anti-kidney vortices. Although this leads to a slightly shorter length of coolant trace, the area-averaged cooling effectiveness can be increased by 66% within the downstream range of 40D.

Presenting Author: Yiming Luo Beihang University

Presenting Author Biography: Yiming Luo, the Ph.D student at Research Institute of Aero-Engine in Beihang University. His research interests mainly include film cooling technique, shaped hole design and cooling optimisation for gas turbines.

Authors:

Yiming Luo Beihang University
Haiwang Li Beihang University
Zhiyu Zhou Beihang University
Gang Xie Beihang University
Long Meng Beihang University