Improvement of film cooling effectiveness with a small downstream block body

Khorsi, Azzeddine; Guelailia, A.; Hamidou, M.

doi:10.1134/s0021894416040106

Cited by 10 publications

(5 citation statements)

References 21 publications

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“…One of the latest techniques to optimize the overall performance of film cooling is adding an obstacle configuration downstream the coolant perforation. Results presented in the work of Khorsi et al [19] indicated that the block shaped as a crescent promises significant enhancement of cooling effectiveness. Recently, the effect of longitudinal curvature on film cooling performance was analyzed by Guelailia et al [20].…”

Section: Introductionmentioning

confidence: 99%

Effects of Crescent Shaped Block Width and Length on Flow Field and Film Cooling Performance

Guelailia¹,

Khorsi

Ahmed³

et al. 2023

Trends Sci

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Turbine blades and rocket nozzles can be efficiently protected from combustion chamber exhaust hot gases by film cooling technic. A crescent-shaped block placed downstream of the injection hole can significantly improve cooling effectiveness. The main objective of this research work is to investigate the inﬂuence of the crescent-shaped block length and width on film cooling effectiveness. ANSYS CFX was used to conduct analysis of a flat plate configuration with cylindrical holes. Nine configurations of the crescent shaped blocks were considered. For each case, the effect of blowing ratios (0.5 and 1) was investigated. The turbulence model shear stress transport (SST) is used for approximating turbulence. Good agreement was obtained by comparing the analysis results with the experimental data. The result indicated that block width variation has a considerable impact on film cooling performance. However, slight effect of block length on cooling effectiveness was obtained. Comparing all analyzed configurations, the best cooling effectiveness was reached for the model 9 (W = 3d, B = 1.5d). HIGHLIGHTS Rocket nozzles can be efficiently protected from combustion chamber exhaust hot gases by film cooling technic One of the latest techniques to optimize the overall performance of film cooling is adding an obstacle configuration downstream the coolant perforation Film cooling performance is considerably enhanced by placing a crescent shaped block downstream the injection hole The maximum enhancement in overall film cooling effectiveness using the optimal configuration (model 6: W = 2d, B = 1.5d) is about 252 % achieved at a blowing ratio of M = 1 GRAPHICAL ABSTRACT

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Section: Introductionmentioning

confidence: 99%

Effects of Crescent Shaped Block Width and Length on Flow Field and Film Cooling Performance

Guelailia¹,

Khorsi

Ahmed³

et al. 2023

Trends Sci

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show abstract

“…Placing an obstacle downstream the injection hole is one of the new ways to enhance film cooling flow distribution on the cooled surface. For example, crescentshaped block configuration promises significant improvement in film cooling as reported in the research work of Khorsi et al 20 Recently, Zhang et al 21 investigated the effect of crescent-shaped block streamwise position on flat plate film cooling characteristics. Hefang et al 22 numerically studied the effects of four types of winglet vortex generators upstream of the film hole on film cooling performance.…”

Section: Introductionmentioning

confidence: 99%

Effect of lid height and blowing ratio on film cooling effectiveness of a novel lidded hole configuration

Guelailia

Khorsi

Slimane

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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Film cooling is one of the promising technologies used for protecting rocket nozzles and turbine blades from combustion chamber hot gases. This paper proposes a novel shape of film cooling injection hole, called lidded hole, that can offer significant enhancement of cooling performance. ANSYS CFX is used to perform 3D numerical simulations of a flat plate with a single row of lidded holes, in which the k–ε model approximates turbulence effects. Four cases are investigated to highlight the influence of the hole's lid height (H/d = 0, 0.25, 0.5, 0.75). The effect of blowing ratios (M = 0.5, 1, 1.5) is also analyzed for each configuration. The numerical results of this study are compared with available experimental data, and, generally, a good agreement is achieved. The results obtained show that the lidded hole configuration reduces the coolant flow separation which improves significantly the film cooling effectiveness. In addition, increasing the blowing ratio leads to an increase in lateral and centerline cooling effectiveness. Comparing all studied cases, the optimum coolant coverage was obtained for the lidded hole configuration with H/d = 0.25 at M = 1.5.

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“…The experimental results showed that the cooling effectiveness can be improved at blowing ratios ranging from 0.5 to 1.25. The crescent-shaped block downstream the hole was also numerically evaluated by Khorsi et al [17].…”

Section: Introductionmentioning

confidence: 99%

“…In the review of the literature [7][8][9][10][11][12][13][14][15][16][17], several specific block shapes were opposed. Except for the block shape [7][8][9][10][11][12][13][14][15][16][17], the height of the block also has a great impact on the cooling performance and aerodynamic loss. Based on the results in [9][10][11], higher protrusions or vortex generators upstream the hole resulted in better cooling performance but also higher aerodynamic loss.…”

Section: Introductionmentioning

confidence: 99%

Influence of streamwise position of crescent-shaped block on flat-plate film cooling characteristics

Zhang

Wang

2019

J Braz. Soc. Mech. Sci. Eng.

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Film cooling injection from discrete circular holes is widely used in gas turbines to reduce the heat load of the turbine blades. Placing a special designed structure upstream or downstream, the circular hole has been proven to be a new effective way to improve cooling effectiveness in recent years. In the present study, numerical investigations were performed on a row of circular holes over a flat plate with crescent-shaped blocks. Totally seven configurations without block, with blocks located at six streamwise positions including 6 times, 5 times, 4 times of hole diameter upstream, and 0.5 times, 1.5 times, 2.5 times of hole diameter downstream at blowing ratios of 0.5-1.5 were tested symmetrically. The Reynolds-averaged Navier-Stokes equations with the k-ω shear-stress transport model were solved. Flow fields, cooling effectiveness and aerodynamic losses were analyzed in detail. Although with different generation mechanism, additional vortex pair opposite to the counter-rotating vortex pair was generated by placing either an upstream or downstream block, which could finally improve the coolant lateral coverage and thus cooling effectiveness. The cooling performances and aerodynamic losses between configurations without block and with blocks at six streamwise positions were then compared. Finally, the optimal streamwise position of the block was recommended at various blowing ratios.

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Improvement of film cooling effectiveness with a small downstream block body

Cited by 10 publications

References 21 publications

Effects of Crescent Shaped Block Width and Length on Flow Field and Film Cooling Performance

Effects of Crescent Shaped Block Width and Length on Flow Field and Film Cooling Performance

Effect of lid height and blowing ratio on film cooling effectiveness of a novel lidded hole configuration

Influence of streamwise position of crescent-shaped block on flat-plate film cooling characteristics

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