Effect of coolant–mainstream blowing ratio on leading edge film cooling flow and heat transfer – LES investigation

Rozati, Ali; Tafti, Danesh K.

doi:10.1016/j.ijheatfluidflow.2008.02.007

Cited by 54 publications

(18 citation statements)

References 37 publications

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“…The moderate blowing ratios (M=0.6 or M=0. 9) show better film cooling effectiveness on either pressure side or suction side immediately downstream of the film cooling holes. Further downstream of the film cooling holes, high blowing ratios provide wider film coverage.…”

Section: Nomenclaturementioning

confidence: 95%

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Experimental investigation on film cooling performance of pressure side in annular cascades

Deng

2011

J. Therm. Sci.

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Experimental investigations were conducted to study the film cooling performance in a low speed annular cascades using Thermochromic Liquid Crystal (TLC) technique. The test blade was placed in the second stage, where 18 blades were installed with chord length of 124.3 mm and height of 99 mm. A film hole with diameter of 4 mm, angled 28° to the tangential of the pressure surface in streamwise, was set in the middle span of the blade.The Reynolds number based on the outlet mainstream velocity and the blade chord length of the second stage varied from 1.52×10 5 to 2.00×10 5 . All measurements were made with the blowing ratio varying from 0.3 to 3.0. Air and CO 2 worked as coolant to achieve the coolant-to-mainstream density ratio of 1.03 and 1.57. The results show that the film coverage and cooling effectiveness scale up with the blowing ratio. Higher density ratio can generate larger film cooling coverage and effectiveness. The higher the Reynolds number, the larger the film coverage and cooling effectiveness.

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Section: Nomenclaturementioning

confidence: 95%

“…Bayraktar et al [8] tested three two-equation turbulence models and found that increasing blowing ratio can increase the film cooling effectiveness. Rozati and Tafti [9] used Large Eddy Simulation (LES) to analyze and quantify the effects of blowing ratio in leading edge film cooling. Three blowing ratios of 0.4, 0.8, and 1.2 were studied.…”

Section: Nomenclaturementioning

confidence: 99%

Experimental investigation on film cooling performance of pressure side in annular cascades

Deng

2011

J. Therm. Sci.

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“…For example, Rozati and Tafti (2008), Renze et al (2006), and Ramezanizadeh et al (2007), conducted some researches on the effects of mass, momentum and density ratios on the jet into cross flow penetration, flow mixing and film cooling effectiveness. Saumweber et al (2003), studied the effects of turbulence level of the cross flow or the jet on the flow hydrodynamics and cooling performance.…”

Section: Introductionmentioning

confidence: 99%

Film Cooling Effectiveness Enhancement Applying another Jet in the Upstream Neighbor of the Main Jet-Using LES Approach

Salimi

Ramezanizadeh

Taeibi-Rahni

et al. 2016

JAFM

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Flow hydrodynamic effects and film cooling effectiveness of placing a coolant port (upstream jet) just upstream of the main cooling jet were numerically investigated. The upstream jet was added such that the total cooling cross section (cross sections of the main and upstream jets) remains constant, in comparison to the case of ordinary cooling jet. The finite volume method and the unsteady SIMPLE algorithm on a multiblock non-uniform staggered grid arrangement were applied. The large eddy simulation (LES) approach with the one equation subgrid scale model was used. The jet to cross flow velocity ratio (for both of the main and the upstream jets) is 0.5 and the cross flow Reynolds number (based on the main jet parameters) is equal to 4700. The obtained results showed a significant improvement in the flow control capability and both centerline and span-wise averaged film cooling effectiveness applying the new cooling configuration. Effects of the upstream jet dimensions are also studied here. The obtained results showed that the span-wise width of the upstream jet has more essential influence on the cooling performance than that of its stream-wise width. Moreover, it is demonstrated that the film cooling performance could be enhanced even by applying an upstream jet which its temperature is as same as the cross-flow temperature, i.e. applying a hot upstream jet. Finally, it is shown that presence of the upstream jet decreases the stream-wise component of the velocity near the wall, which decreases the wall shear stress and the skin friction drag coefficient significantly.

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“…[2][3][4][5] (2) Flow characteristics, including blow ratio, turbulence intensity, Reynolds number and density ratio, etc. [6][7][8] The technology of plasma actuators for active flow control has been conducted by many researchers in the last few decades. [9][10][11][12] It is demonstrated that plasma actuator is capable of delaying the separation of airfoils, adding momentum to the induced flow and enabling high speed jet control, etc.…”

Section: Introductionmentioning

confidence: 99%

Computational study of plasma actuator on film cooling performance for different shaped holes

Dai

Yang

et al. 2015

AIP Advances

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An investigation on film cooling holes with plasma actuators are performed for circular hole, expansion-shaped hole and fan-shaped hole on the surface of flat plate. The results are compared with those obtained from the same combination of varied shaped holes without plasma actuator. Computational results suggest that plasma-induced body force mitigates the intensity of the counter rotating vortex pair by creating a new pair of vortexes, thereby providing greater coolant-surface attachment for each hole shape, resulting in the improvement of film cooling effectiveness. As for the holes of varied shapes with plasma actuator, the expansion-shaped hole shows superior laterally averaged film cooling effectiveness to that of the circular hole. Comparing with the abovementioned two shaped holes, the fan-shaped one performs worse in terms of laterally averaged film cooling effectiveness at low blow ratios, and better at high blow ratios. The fan-shaped hole also provides the best uniformity of film cooling effectiveness among all cases.

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Effect of coolant–mainstream blowing ratio on leading edge film cooling flow and heat transfer – LES investigation

Cited by 54 publications

References 37 publications

Experimental investigation on film cooling performance of pressure side in annular cascades

Experimental investigation on film cooling performance of pressure side in annular cascades

Film Cooling Effectiveness Enhancement Applying another Jet in the Upstream Neighbor of the Main Jet-Using LES Approach

Computational study of plasma actuator on film cooling performance for different shaped holes

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