Session: 12-02: End-wall and Tip Film Cooling

Paper Number: 152365

On the Impact of Upstream Bump Geometry on the Aerothermal Performance of a 7-7-7 Shaped Hole 

A way to increase film cooling effectiveness levels downstream of film cooling holes is through a modification in the surface morphology upstream of the hole. The presence of a bump in front of the hole, if properly sized, can reduce the jet to mainstream interaction, resulting in a more laterally uniform coolant layer. The performance of this solution depends on the bump geometrical characteristics, namely its height and width, and on the distance from the hole. An LES based numerical investigation has been performed at Korea University to optimize the bump geometry, resulting in an optimal configuration allowing a 17% increase in cooling performance at constant operating conditions. The present paper reports the results of a combined experimental investigation carried out at Bergamo University on a Plexiglas flat plate model with a set of three fan-shaped holes incorporated into an existing wind tunnel, replicating the numerical setup. PSP and PIV techniques were used to characterize the flow behavior and the adiabatic film cooling effectiveness of the standard shaped hole case and of the best and worst bump configuration coming from LES optimization procedure. The aero-thermal performance has been examined at different coolant to mainstream blowing ratios M in the range between 1 and 2. This data set allows to fully assess the performance of the bump when applied to fan-shaped holes and to further appreciate the prediction capability of LES approach in simulating film cooling related phenomena.

Presenting Author: Giovanna Barigozzi Università di Bergamo

Presenting Author Biography: Giovanna Barigozzi is full professor of Fluid Machinery at Bergamo University, Italy. Her research activity is mainly focused on the experimental investigation of film cooling aero-thermal performance.

Authors:

Giovanna Barigozzi Università di Bergamo
Ali Zamiri Korea University
Giovanni Brumana Università di Bergamo
Mauro Carnevale Università di Bergamo
Jin Taek Chung Korea University