Film Cooling From a Row of Holes Supplemented With Antivortex Holes

Dhungel, Alok; Lu, Yiping; Phillips, Wynn Allen; Ekkad, Srinath V.; Heidmann, James D.

doi:10.1115/1.2950059

Cited by 92 publications

(18 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent study by Dhungel et al (2009) deals with the film cooling performance of a flat plate with a row of simple holes and with the same holes, either complemented with two smaller symmetrical anti-vortex holes, which branch out from the main hole, or shaped at their exit. The proposed anti-vortex design requires only easily machinable round holes, unlike shaped holes, and is intended to counteract the detrimental vorticity associated with standard circular cross-section holes.…”

Section: Film Coolingmentioning

confidence: 99%

Infrared thermography for convective heat transfer measurements

2010

View full text Add to dashboard Cite

This paper deals with the evolution of infrared (IR) thermography into a powerful optical tool that can be used in complex fluid flows to either evaluate wall convective heat fluxes or investigate the surface flow field behavior. Measurement of convective heat fluxes must be performed by means of a thermal sensor, where temperatures have to be measured with proper transducers. By correctly choosing the thermal sensor, IR thermography can be successfully exploited to resolve convective heat flux distributions with both steady and transient techniques. When comparing it to standard transducers, the IR camera appears very valuable because it is non-intrusive, it has a high sensitivity (down to 20 mK), it has a low response time (down to 20 ls), it is fully two dimensional (from 80 k up to 1 M pixels, at 50 Hz) and, therefore, it allows for better evaluation of errors due to tangential conduction within the sensor. This paper analyses the capability of IR thermography to perform convective heat transfer measurements and surface visualizations in complex fluid flows. In particular, it includes the following: the necessary radiation theory background, a review of the main IR camera features, a description of the pertinent heat flux sensors, an analysis of the IR image processing methods and a report on some applications to complex fluid flows, ranging from natural convection to hypersonic regime.

show abstract

Section: Film Coolingmentioning

confidence: 99%

Infrared thermography for convective heat transfer measurements

2010

View full text Add to dashboard Cite

show abstract

“…The primary focus of this paper is to study the film cooling performance for a row of cylindrical holes each supplemented with two symmetrical anti vortex holes which branch out from the main Fig. 18 Design of anti-vortex holes and different configurations by Dhungel et al (2009).…”

Section: -2014mentioning

confidence: 99%

“…This would simplify manufacturing and ease concerns about drilling very small holes. Dhungel et al (2009) presented a detailed study on the effects of geometry and orientations of anti-vortex holes branching out from the primary holes on film cooling have been presented. For all the cases, both heat transfer coefficients and film effectiveness were measured using a transient infrared thermography technique.…”

Section: -2014mentioning

confidence: 99%

“…When the anti vortex holes are nearer to the primary film cooling holes and are developing from the base of the primary holes, better film cooling was accomplished as compared to other anti vortex hole orientations. Narzary et al (2011) presented a new anti-vortex design geometry where the two side holes, also of the same diameter, branch out from the root at 15 o angle based on Dhungel et al (2009). The pitch-to-diameter ratio was increased to 6.0 between the main holes.…”

Section: -2014mentioning

confidence: 99%

See 1 more Smart Citation

A Review of Hole Geometry and Coolant Density Effect on Film Cooling

Ekkad¹,

Han²

2015

Frontiers in Heat and Mass Transfer

View full text Add to dashboard Cite

Improved film cooling hole geometries and effect of coolant density on film cooling have been a focus since the 1970s. One of the first studies on modifying hole exit to improve film cooling effectiveness and quantifying coolant density effect was from Prof. Goldstein's group. This paper provides an overview of the development and implementation of hole exit geometries as well as coolant density study over the past few decades and the impact on future studies of advanced hole geometries under realistic engine-like coolant-to-mainstream density ratio conditions. This work is not intended to be a comprehensive review of the literature.

show abstract

“…Finally, the interaction of multiple, closely-spaced holes is beneficial to the cooling effectiveness. Either multiple rows, arranged from in-line to staggered [7], or arrays of holes are employed [8][9][10]. The interaction of the holes modifies the dominant vortices or improves the spanwise coverage of the coolant.…”

Section: Introductionmentioning

confidence: 99%

Flow-field analysis of anti-kidney vortex film cooling

Gräf

Kleiser

2012

J. Therm. Sci.

View full text Add to dashboard Cite

Film cooling is an important measure to enable an increase of the inlet temperature of a gas turbine and, thereby, to improve its overall efficiency. The coolant is ejected through spanwise rows of holes in the blades or endwalls to build up a film shielding the material. The holes often are inclined in the downstream direction and give rise to a kidney vortex. This is a counter-rotating vortex pair, with an upward flow direction between the two vortices, which tends to lift off the surface and to locally feed hot air towards the blade outside the pair. Reversing the rotational sense of the vortices reverses these two drawbacks into advantages. In the considered case, an anti-kidney vortex is generated using two subsequent rows of holes both inclined downstream and yawed spanwise with alternating angles. In a previous study, we performed large-eddy simulations (which focused on the fully turbulent boundary layer) of this anti-kidney vortex film-cooling and compared them to a corresponding physical experiment. The present work analyzes the simulated flow field in detail, beginning in the plenum (inside the blade or endwall) through the holes up to the mixture with the hot boundary layer. To identify the vortical structures found in the mean flow and in the instantaneous flow, we mostly use the λ 2 criterion and the line integral convolution (LIC) technique indicating sectional streamlines. The flow regions (coolant plenum, holes, and boundary layer) are studied subsequently and linked to each other. To track the anti-kidney vortex throughout the boundary layer, we propose two criteria which are based on vorticity and on LIC results. This enables us to associate the jet vortices with the cooling effectiveness at the wall, which is the key feature of film cooling.

show abstract

Film Cooling From a Row of Holes Supplemented With Antivortex Holes

Cited by 92 publications

References 13 publications

Infrared thermography for convective heat transfer measurements

Infrared thermography for convective heat transfer measurements

A Review of Hole Geometry and Coolant Density Effect on Film Cooling

Flow-field analysis of anti-kidney vortex film cooling

Contact Info

Product

Resources

About