Turbine Blade Platform Film Cooling With Typical Stator-Rotor Purge Flow and Discrete-Hole Film Cooling

Abstract

This paper is focused on the effect of film-hole configurations on platform film cooling. The platform is cooled by purge flow from a simulated stator-rotor seal combined with discrete-hole film cooling within the blade passage. The cylindrical holes and laidback fan-shaped holes are assessed in terms of film-cooling effectiveness and total pressure loss. Lined up with the freestream streamwise direction, the film holes are arranged on the platform with two different layouts. In one layout, the film-cooling holes are divided into two rows and more concentrated on the pressure side of the passage. In the other layout, the film-cooling holes are divided into four rows and loosely distributed on the platform. Four film-cooling hole configurations are investigated totally. Testing was done in a five-blade cascade with medium high Mach number condition (0.27 and 0.44 at the inlet and the exit, respectively). The detailed film-cooling effectiveness distributions on the platform were obtained using pressure sensitive paint technique. Results show that the combined cooling scheme (slot purge flow cooling combined with discrete-hole film cooling) is able to provide full film coverage on the platform. The shaped holes present higher film-cooling effectiveness and wider film coverage than the cylindrical holes, particularly at higher blowing ratios. The hole layout affects the local film-cooling effectiveness. The shaped holes also show the advantage over the cylindrical holes with lower total pressure loss.

Film Cooling of Cylindrical Hole With a Downstream Short Crescent-Shaped Block

“…Woodmansee and Dutton [27] gave four treatment methods to reduce the influence of temperature. Gao et al [28] also presented the method to eliminate the influence of temperature. Actually, the emitting light intensity can be described as Eq.…”

Turbine Blade Film Cooling Using PSP Technique

“…More recently, the improvement in film cooling due to the usage of shaped holes in the end-wall has been studied by Barigozzi et al (2007), Colban et al (2008) and Gao et al (2009a). The effect of coolant density ratio on film cooling effectiveness was studied by Narzary et al (2009), with the conclusion that higher density coolants are more resilient to lift-off and result in higher film cooling effectiveness.…”

“…Wright et al (2009) tested the effect of upstream wakes generated by wake rods and delta wings to simulate the effect of upstream stator wakes and end-wall vortices, with the conclusion that the delta wings produce a larger negative effect on film cooling. Gao et al (2009a) ran tests on a turbine blade end-wall filmcooling under moderate Mach number conditions (Ma in =0.27 and Ma ex =0.44. Combined purge and discrete hole film cooling with DR = 1.0 was studied by the PSP technique.…”

Influence of the pressure side injection slot on the cooling performance of endwall surface

“…He indicated that geometric parameters had a significant influence on the endwall cooling effectiveness, and developing novel shaped holes was still an important way to increase the cooling effectiveness. The study by Gao et al [7] indicated that shaped holes presented a higher cooling effectiveness and wider coolant coverage on the blade platform than normal cylindrical holes, especially at higher blowing ratios. They found that the shaped hole contributed to enhance the lateral expansion of the coolant jet, resulting in larger coolant coverage.…”