Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance

Abstract

This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D Laser Doppler Velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a higher FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line.

Combined-hole film cooling with the application of double flow control devices

“…One of the effectiveness way to control the formation of the kidney vortex and improve the film cooling effect is by adding devices upstream or downstream of the cooling holes and changing the geometry of film cooling hole. Takisawa et al [5] and Kawabata et al [6] added the flow control devices upstream of the cylindrical film cooling hole which been reported to altered the formation of the kidney vortex while improving the film cooling performance. Meanwhile, other the research [7][8][9] have also reported improvement on the film cooling performance through combined-hole configuration which is achieved by combining two film cooling holes together as a unit.…”