Flow visualization and film cooling effectiveness measurements around shaped holes with compound angle orientations

Lee, Hong-Wook; Park, Jung-Joon; Lee, Joon Sik

doi:10.1016/s0017-9310(01)00112-0

Cited by 34 publications

(18 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The drop in effectiveness along the test section is less for the liquid injection at high coolant injection pressures. 6. It was noted that a relatively stable film prevails for low core gas temperature and higher injection pressure tends to reduce the film uniformity.…”

Section: Discussionmentioning

confidence: 99%

“…Ekkad et al [5] reported film cooling effectiveness results for compound angle holes with relatively high turbulence intensity and found that higher density injectant tends to result in a higher film cooling effectiveness for simple injection, while lower density coolant results in a higher effectiveness for a large compound angle. Lee et al's [6] experimental studies showed improved effectiveness at high blowing ratios for compound angle shaped holes. However the occurrence of hot cross flow ingestion into the film hole at the hole exit plane was observed for large orientation angles.…”

Section: Gaseous Film Cooling Studiesmentioning

confidence: 99%

“…A significant increase in the film cooling effectiveness was reported by him. Many studies are available for film coolant measurements over a flat plate surface with a stream wise angle injection of 35°and with compound angle injection [2][3][4][5][6]. They all reported that compound angle injection provided better lateral coverage and mixing of jets with the main stream.…”

Section: Gaseous Film Cooling Studiesmentioning

confidence: 99%

See 2 more Smart Citations

Influence of coolant injector configuration on film cooling effectiveness for gaseous and liquid film coolants

2011

View full text Add to dashboard Cite

An experimental investigation is conducted to bring out the effects of coolant injector configuration on film cooling effectiveness, film cooled length and film uniformity associated with gaseous and liquid coolants. A series of measurements are performed using hot air as the core gas and gaseous nitrogen and water as the film coolants in a cylindrical test section simulating a thrust chamber. Straight and compound angle injection at two different configurations of 30°-10°and 45°-10°are investigated for the gaseous coolant. Tangential injection at 30°and compound angle injection at 30°-10°are examined for the liquid coolant. The analysis is based on measurements of the film-cooling effectiveness and film uniformity downstream of the injection location at different blowing ratios. Measured results showed that compound angle configuration leads to lower far-field effectiveness and shorter film length compared to tangential injection in the case of liquid film cooling. For similar injector configurations, effectiveness along the stream wise direction showed flat characteristics initially for the liquid coolant, while it was continuously dropping for the gaseous coolant. For liquid coolant, deviations in temperature around the circumference are very low near the injection point, but increases to higher values for regions away from the coolant injection locations. The study brings out the existance of an optimum gaseous film coolant injector configuration for which the effectiveness is maximum.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Gaseous Film Cooling Studiesmentioning

confidence: 99%

Section: Gaseous Film Cooling Studiesmentioning

confidence: 99%

See 1 more Smart Citation

Influence of coolant injector configuration on film cooling effectiveness for gaseous and liquid film coolants

2011

View full text Add to dashboard Cite

show abstract

“…Sinha et al [7] investigated the effect of density ratio on film cooling effectiveness. Ekkad et al [8] and Lee et al [9] perfromed experimental investigations on the influence of compound angle (the cooling hole angle relative to the freestream flow in the lateral direction) in film cooling characteristics for cylindrical holes and shaped holes, respectively.…”

Section: Experimental Investigationsmentioning

confidence: 99%

On Film Cooling of Turbine Guide Vanes : From Experiments and CFD-Simulations to Correlation Development

Najafabadi¹

2015

View full text Add to dashboard Cite

To achieve high thermal efficiency in modern gas turbines, the turbine-inlet temperature has to be increased. In response to such requisites and to prevent thermal failure of the components exposed to hot gas streams, the use of different cooling techniques, including film cooling, is essential. Finding an optimum film cooling design has become a challenge as it is influenced by a large number of flow and geometrical parameters. This study is dedicated to some important aspects of film cooling of a turbine guide vane and consists of three parts. The first part is associated with an experimental investigation of the suction and pressure side cooling by means of a transient IR-Thermography technique under engine representative conditions. It is shown that the overall film cooling performance of the suction side can be improved by adding showerhead cooling if fan-shaped holes are used, while cylindrical holes may not necessarily benefit from a showerhead. According to the findings, investigation of an optimum cooling design for the suction side is not only a function of hole shape, blowing ratio, state of approaching flow, etc., but is also highly dependent on the presence/absence of showerhead cooling as well as the number of cooling rows. In this regard, it is also discussed that the combined effect of the adiabatic film effectiveness (AFE) and the heat transfer coefficient (HTC) should be considered in such study. As for the pressure side cooling, it is found that either the showerhead or a single row of cylindrical cooling holes can enhance the HTC substantially, whereas a combination of the two or using fan-shaped holes indicates considerably lower HTC. An important conclusion is that adding more than one cooling row will not augment the HTC and will even decrease it under certain circumstances. In the second part, computational fluid dynamics (CFD) investigations have shown that film cooling holes subjected to higher flow acceleration will maintain a higher level of AFE. Although this was found to be valid for both suction and pressure side, due to an overall lower acceleration for the pressure side, a lower AFE was achieved. Moreover, the CFD results indicate that fan-shaped holes with low area ratio (dictated by design constraints for medium-size gas turbines), suffer from cooling jet separation and hence reduction in AFE for blowing ratios above unity. Verification of these conclusions by experiments suggests that CFD can be used more extensively, e.g. for parametric studies. The last part deals with method development for deriving correlations based on experimental data to support engineers in the design stage. The proposed method and the ultimate correlation model could successfully correlate the laterally averaged AFE to the downstream distance, the blowing ratio and the local pressure coefficient representing the effect of approaching flow. The applicability of the method has been examined and the high level of predictability of the final model demonstrates its suitability to be used for design purposes...

show abstract

“…Researches performed by Narzary and Han (2008), , and An et al (2013), are some examples. Second; researches have performed to improve the coolant distribution over the surface by varying the jet injection angle in different ways such as researches performed by Lee et al (2002), Hung et al (2009), , and Acharya and Leedom (2013), Third; researches have done to increase the film cooling coverage and effectiveness by managing jets arrangement (jets locations relative to each other). Relatively, fewer researches on this area have been reported in the literature.…”

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

View full text Add to dashboard Cite

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.

show abstract

Flow visualization and film cooling effectiveness measurements around shaped holes with compound angle orientations

Cited by 34 publications

References 14 publications

Influence of coolant injector configuration on film cooling effectiveness for gaseous and liquid film coolants

Influence of coolant injector configuration on film cooling effectiveness for gaseous and liquid film coolants

On Film Cooling of Turbine Guide Vanes : From Experiments and CFD-Simulations to Correlation Development

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

Contact Info

Product

Resources

About