Cooling effectiveness of shaped film holes for leading edge

Elnady, Tarek; Hassan, Ibrahim; Kadem, Lyes; Lucas, Terry

doi:10.1016/j.expthermflusci.2012.09.005

Cited by 17 publications

(3 citation statements)

References 22 publications

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“…Turbine blades work in extreme conditions, including high temperature, high pressure, and huge centrifugal force. The demand for increasing thermal efficiencies results in the sustaining improvement of turbine entry temperature and the requirement of advanced cooling technologies for turbine blades [1]. For the internal cooling of turbine blades, the most critical portion is the leading edge because that position is exposed to the highest heat flux and pressure with a narrow space and a high-curvature surface [2].…”

Section: Introductionmentioning

confidence: 99%

Cooling Characteristic of a Wall Jet for Suppressing Crossflow Effect under Conjugate Heat Transfer Condition

Deng

Feng

2022

Aerospace

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The leading edge is the critical portion for a gas turbine blade and is often insufficiently cooled due to the adverse effect of Crossflow in the cooling chamber. A novel internal cooling structure, wall jet cooling, can suppress Crossflow effect by changing the coolant flow direction. In this paper, the conjugate heat transfer and aerodynamic characteristics of blades with three different internal cooling structures, including impingement with a single row of jets, swirl cooling, and wall jet cooling, are investigated through RANS simulations. The results show that wall jet cooling combines the advantages of impingement cooling and swirl cooling, and has a 19–54% higher laterally-averaged overall cooling effectiveness than the conventional methods at different positions on the suction side. In the blade with wall jet cooling, the spent coolant at the leading edge is extracted away through the downstream channels so that the jet could accurately impinge the target surface without unnecessary mixing, and the high turbulence generated by the separation vortex enhances the heat transfer intensity. The Coriolis force induces the coolant air to adhere to the pressure side’s inner wall surface, preventing the jet from leaving the target surface. The parallel cooling channels eliminate the common Crossflow effect and make the flow distribution of the orifices more uniform. The trailing edge outlet reduces the entire cooling structure’s pressure to a low level, which means less penalty on power output and engine efficiency.

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Section: Introductionmentioning

confidence: 99%

Cooling Characteristic of a Wall Jet for Suppressing Crossflow Effect under Conjugate Heat Transfer Condition

Deng

Feng

2022

Aerospace

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“…This technology was also one of the hotspots in the research of aeroengine cooling technology in recent years [17]. Elnadya et al [18] studied the cooling effectiveness of expanded holes on the leading edge of NGV and found that the cooling effectiveness of a cooling hole was proportional to blowing ratio, and the stress at the hole edges varied smoothly. Moritz et al [19] studied film cooling holes at the leading edge of NGV by thermal-fluid coupling calculations.…”

Section: Introductionmentioning

confidence: 99%

An Enhanced Flow-Thermo-Structural Modeling and Validation for the Integrated Analysis of a Film Cooling Nozzle Guide Vane

Guan

Fei

2019

Energies

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The target of this paper is to develop an enhanced flow-thermo-structural (FTS) model with high computational accuracy, to perform the integrated analysis of film cooling nozzle guide vane (NGV). An efficient turbulence model and weak spring approach are utilized in the enhanced FTS model. In respect of the power balance principle of aeroengine rotor shaft and temperature test of a typical combustor, the mean temperature inlet and five normalization temperature curves were confirmed, respectively. The temperature-sensitive paint (TSP) technology was used to verify the numerical simulation. From this study, we find that the predicted temperature caters for the TSP test well, between which the maximum error is less than 6%, and the maximum thermal stress is 758 MPa around the hole edges and the location of stress concentration keeps the consistency with that of the cracks. The maximum thermal stress increases by 10% with the increasing inlet temperature and reduces by about 16% with the shifting of flame peak from the outer to inner hub. The prediction provides general information on the initiation of cracks on a vane segment. The developed enhanced FTS model is validated to be workable and precise in the integrated analysis of film cooling NGV. The efforts of this study provide an integrated analysis approach of film cooling NGV and are promising to provide guidance for the integrated design of film cooling components besides NGV.

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“…Lee and Kim [11] studied the film-cooling performance of the novel shaped holes by comparison with that of fan-shaped holes; overall, with an increase in the blowing ratio, the novel shaped hole shows greatly improved film cooling effectiveness and lateral spreading of coolant. Elnady et al [12] presented an experimental investigation performed to evaluate the employment of smooth expansion hole positioned at the leading edge of a gas turbine stator. Two expansion levels, 2d and 4d have been investigated in addition to the standard cylindrical hole at two inclination angles, [13].…”

Section: Introductionmentioning

confidence: 99%

Coupling of internal and external cooling of gas turbine blades

Ghezali

Azzi

Bouzidane

2014

Mechanics & Industry

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Showerhead cooling process which consists of internal convective cooling and external film cooling of a turbine blade is investigated using ANSYS-CFX software. The aim of the present investigation is to provide a better understanding of the fundamental nature of showerhead cooling using the three dimensional Reynolds averaged Navier Stokes analysis. A numerical model has been developed to study the effects of coupled internal and external cooling of the leading edge for a semi-elliptical body shape with the SST k-ω model. This model consists of all internal flow passages and cooling hole rows at the leading edge. The numerical results obtained are discussed and compared with experimental data available in the literature. The results show that the cooling efficiency increases with the increase of the blowing ratio and the Mach number, therefore, the overall efficiency for the steel becomes less important compared to the plexiglas which has a low thermal conductivity.

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Cooling effectiveness of shaped film holes for leading edge

Cited by 17 publications

References 22 publications

Cooling Characteristic of a Wall Jet for Suppressing Crossflow Effect under Conjugate Heat Transfer Condition

Cooling Characteristic of a Wall Jet for Suppressing Crossflow Effect under Conjugate Heat Transfer Condition

An Enhanced Flow-Thermo-Structural Modeling and Validation for the Integrated Analysis of a Film Cooling Nozzle Guide Vane

Coupling of internal and external cooling of gas turbine blades

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