Effect of Crossflows on the Discharge Coefficient of Film Cooling Holes

Hay, N.; Lampard, D.; Benmansour, Saad

doi:10.1115/1.3227408

Cited by 53 publications

(29 citation statements)

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“…This is termed the 'crossover' phenomenon by the authors. The data is most comparable to the sharp edged hole data presented by Hay et al (1983;lid = 6.0, 0 = 90°, a = 0°, Me = 0.3 and M" = 0.11) which not only gives similar absolute values of Cd but also exhibits the crossover phenomenon. This is also the most suitable data that is available for comparison with that presented for Rows 4 and 5 (Figures 9 and 10 respectively).…”

Section: Measurements With External Crossflowsupporting

confidence: 85%

Engine Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade

Rowbury

Oldfield

Lock

1997

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery

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This paper discusses measurements of the discharge coefficients of gas turbine nozzle guide vane film cooling holes under fully engine representative conditions. These unique experiments were carried out in a large scale annular blowdown cascade which models the three-dimensional external, flow patterns found in modern aero-engines, including all secondary flow phenomena. Furthermore, the coolant system design allows the coolant-to-mainstream density ratio and blowing parameter to be matched to engine values, although they can be independently varied. The results confirm that the discharge coefficients of film cooling holes are significantly altered by external crossflow. The discharge coefficient is usually reduced by external crossflow, but under certain external flow conditions it can be increased over the non-crossflow case. This previously unhightighted phenomenon has been termed ‘the crossover effect’, and, although an initially surprising result, is of importance to aero-engine designers as taking account of it should lead to improved predictions of coolant consumption. As a consequence, more uniform blade cooling should be achieved and, in turn, the attainment of greater component durability will be possible.

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Section: Measurements With External Crossflowsupporting

confidence: 85%

Engine Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade

Rowbury

Oldfield

Lock

1997

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery

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“…Results of the actual study compared to literature data of Hay et al [7], Bunker and Bailey [19], and Saumweber and Schulz [11] are shown in Fig. 4.…”

Section: Resultsmentioning

confidence: 90%

Influence of internal parallel and v-shaped ribs on the discharge coefficient of a cylindrical film cooling hole

Heneka

Schulz

Bauer

2011

Proceedings of the Institution of Mechanical Engineers, Part A:

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An experimental study has been conducted to investigate the discharge behaviour of cylindrical film cooling holes with the main focus on the effects of rib arrangement and crossflow velocity inside the internal cooling passage of a gas turbine blade. Two straight flow channels of rectangular cross-section simulate the crossflow situations present at the inlet and outlet of a film cooling hole. The two channels are connected by a single scaled-up film cooling hole with a diameter of 10 mm, an inclination angle of 30 , and a length-to-diameter ratio of 6. Measurements have been performed at various internal crossflow Mach numbers and rib geometries for both parallel and perpendicular orientations of internal and external crossflows. Parallel and v-shaped ribs with quadratic cross-section and four different angles with respect to the internal crossflow direction (45 , 60 , 75 , and 90 ) have been placed upstream and downstream of the entrance of the hole at one wall of the cooling passage. The rib height equals the hole diameter, the rib pitch to height ratio is 10. The internal crossflow Mach number has been varied between 0 and 0.37.The data show that placing ribs onto the wall of the coolant passage may result in reduced, unchanged, or even increased discharge coefficients. Internal crossflow Mach number and orientation of the coolant passage in respect to the hole axis have been identified as major influencing parameters.

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“…Tan-Atichat, Nagib and Loehrke [1982] measured the dependence of some perforated plates as turbulence manipulators. Most of the film cooling investigations of flow through perforated plates have concentrated on measuring various effects on the discharge coefficients of the holes [Rohde, Richards and Metger, 1969;Hay, Lampard and Benmansour, 1983;Hay, Henshall and Manning, 1994;Gritsch, Schulz und Wittig, 1997;Burd and Simon, 1998]. Burd and Simon [1997] measured the influence of coolant supply geometry on coolant exit flow and Kohli and Thole [1997] applied a CFD calculation for the effects of entrance crossflow directions to film cooling holes.…”

Section: Related Workmentioning

confidence: 99%

Measurements of Fundamental Fluid Physics of SNF Storage Canisters

Condie¹,

Creery²,

McEligot³

2001

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SummaryWith the University of Idaho, Ohio State University and Clarksean Associates, this research program has the long-term goal to develop reliable predictive techniques for the energy, mass and momentum transfer plus chemical reactions in drying / passivation (surface oxidation) operations in the transfer and storage of spent nuclear fuel (SNF) from wet to dry storage. Such techniques are needed to assist in design of future transfer and storage systems, prediction of the performance of existing and proposed systems and safety (re)evaluation of systems as necessary at later dates.Many fuel element geometries and configurations are accommodated in the storage of spent nuclear fuel. Consequently, there is no one generic fuel element / assembly, storage basket or canister and, therefore, no single generic fuel storage configuration. One can, however, identify generic flow phenomena or processes which may be present during drying or passivation in SNF canisters. The objective of the INEEL tasks was to obtain fundamental measurements of these flow processes in appropriate parameter ranges.With the University of Idaho, an idealization of a combined drying and passivation approach has been defined in order to investigate the generic flow processes. This simulation includes flow phenomena that occur in canisters for high-enrichment and medium-enrichment fuels, where fuel element spacing in the canister is increased as compared with low enrichment fuel. Canister diameter was taken as 46 cm (18 in.) and a single basket of about 1.3 meters (4 ft.) length was considered. A long central tube ("dip tube") served as the inlet as in one earlier concept for a passivation process; while this concept apparently has not yet been selected for application, it provides an excellent example of the coupled, complex phenomena which may be present in canister flows. Suggested design flow rates for this hypothesized application indicate that the Reynolds number in the inlet tube would be expected to be between 2500 and 5000, i.e., relatively low.The local distributions of convective mass transfer characteristics (drying/passivation) are expected to depend on the freestream turbulence in the flow around stored fuel elements. The magnitudes of this turbulence depend on the turbulence distributions on the upstream side of the perforated basket support plate ("inlet plenum") and, in turn, in the impinging jet and in the inlet tube. This information can assist engineers in understanding variations of surface drying and passivation through an array and approaches to modify designs to counter non-uniformities and to improve iii distribution, as well as providing bases for assessment of computational fluid dynamics codes proposed for the purpose.A water-flow experiment with a 3/4-scale model (relative to the idealized canister) has been used for overall flow visualization and velocity measurements, with and without an array of simulated fuel elements. Observations have been made with perforated plates (representing basket support plates) having...

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Effect of Crossflows on the Discharge Coefficient of Film Cooling Holes

Cited by 53 publications

References 0 publications

Engine Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade

Engine Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade

Influence of internal parallel and v-shaped ribs on the discharge coefficient of a cylindrical film cooling hole

Measurements of Fundamental Fluid Physics of SNF Storage Canisters

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