scholarly journals Computational investigation of film cooling from cylindrical and row trenched cooling holes near the combustor endwall

2014 ◽  
Vol 4 ◽  
pp. 76-84 ◽  
Author(s):  
Ehsan Kianpour ◽  
Nor Azwadi Che Sidik
Keyword(s):  
Film Cooling ◽  
Computational Investigation

Full-Coverage Film Cooling With Short Normal Injection Holes

2001 ◽  
Vol 123 (4) ◽  
pp. 798-805 ◽  
Author(s):  
Mark K. Harrington ◽  
Marcus A. McWaters ◽  
David G. Bogard ◽  
Christopher A. Lemmon ◽  
Karen A. Thole
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Large Scale ◽  
Infrared Imaging ◽  
Imaging Techniques ◽  
Computational Investigation ◽  
Single Row ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Adiabatic Effectiveness

An experimental and computational investigation was conducted on the film cooling adiabatic effectiveness of a flat plate with full coverage film cooling. The full coverage film cooling array was comprised of ten rows of coolant holes, arranged in a staggered pattern, with short L/D=1, normal coolant holes. A single row of cooland holes was also examined to determine the accuracy of a superposition prediction of the full coverage adiabatic effectiveness performance. Large density coolant jets and high mainstream turbulence conditions were utilized to simulate realistic engine conditions. High-resolution adiabatic effectiveness measurements were obtained using infrared imaging techniques and a large-scale flat plate model. Optimum adiabatic effectiveness was found to occur for a blowing ratio of M=0.65. At this blowing ratio separation of the coolant jet immediately downstream of the hole was observed. For M=0.65, the high mainstream turbulence decreased the spatially averaged effectiveness level by 12 percent. The high mainstream turbulence produced a larger effect for lower blowing ratios. The superposition model based on single row effectiveness results over-predicted the full coverage effectiveness levels.

Full-Coverage Film Cooling With Short Normal Injection Holes

2001 ◽  
Author(s):  
Mark K. Harrington ◽  
Marcus A. McWaters ◽  
David G. Bogard ◽  
Christopher A. Lemmon ◽  
Karen A. Thole
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Large Scale ◽  
Infrared Imaging ◽  
Imaging Techniques ◽  
Computational Investigation ◽  
Single Row ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Adiabatic Effectiveness

An experimental and computational investigation was conducted on the film cooling adiabatic effectiveness of a flat plate with full coverage film cooling. The full coverage film cooling array was comprised of ten rows of coolant holes, arranged in a staggered pattern, with short, L/D = 1, normal coolant holes. A single row of coolant holes was also examined to determine the accuracy of a superposition prediction of the full coverage adiabatic effectiveness performance. Large density coolant jets and high mainstream turbulence conditions were utilized to simulate realistic engine conditions. High-resolution adiabatic effectiveness measurements were obtained using infrared imaging techniques and a large-scale flat plate model. Optimum adiabatic effectiveness was found to occur for a blowing ratio of M = 0.65. At this blowing ratio separation of the coolant jet immediately downstream of the hole was observed. For M = 0.65, the high mainstream turbulence decreased the spatially averaged effectiveness level by 12 percent. The high mainstream turbulence produced a larger effect for lower blowing ratios. The superposition model based on single row effectiveness results over-predicted the full coverage effectiveness levels.

Experimental and Computational Investigation of Film Cooling Performance and External Flowfield Effects due to Impingement Coolant Feed in the Leading Edge of a Turbine Blade

2021 ◽  
Author(s):  
Jacob D. Moore ◽  
Christopher C. Easterby ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Leading Edge ◽  
Field Measurements ◽  
Suction Side ◽  
Computational Investigation ◽  
Exterior Surface ◽  
Cooling Performance ◽  
Root Cause ◽  
Shaped Hole ◽  
Adiabatic Effectiveness

Abstract The effects that leading-edge impingement coolant feeds have on the external flowfield and on film cooling performance in the showerhead have not been studied thoroughly in the literature. To isolate the influence of the impingement feed, experimental adiabatic effectiveness and off-the-wall thermal field measurements were made using a shaped hole geometry fed by an ideal plenum coolant feed and by an engine-realistic impingement coolant feed. The impingement configuration exhibited around 10% higher adiabatic effectiveness levels than the plenum configuration did — a finding in agreement with the few studies isolating this effect. CFD RANS simulations of the impingement and the pseudo-plenum configurations from a companion study were consulted to investigate the root cause of this difference in performance because the experimental data alone did not sufficiently explain it. In the impingement feed simulation, flow remained better attached throughout the hole (both at the inlet and at the diffuser) due to a rotation caused by the impingement flow, leading to better attachment on the exterior surface. This was most significant for the suction side holes at higher blowing ratios wherein the pseudo-plenum caused much more severe separation in the holes than the impingement configuration did.

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