Optimization of the Hole Exit Shaping of Film Holes Without and With Compound Angles for Maximal Film Cooling Effectiveness

Chi, Zhongran; Li, Xueying; Chang, Han; Ren, Jing; Jiang, Hongde

doi:10.1115/gt2014-25212

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…However, the numerical model tends to overestimate the local Nusselt number with errors up to 20% at the stagnation points of the jets. In general, the Several numerical simulations of film-cooling structures, featured with cylindrical holes and shaped holes, were carried out; and the numerical results were validated against experimental data by Sinha et al [23] and experimental data measured by pressuresensitive paint, as introduced in [18] (at room pressure and temperature). As shown in Fig.…”

Section: A Experimental Validation Of Numerical Modelmentioning

confidence: 99%

“…For instance, an array of showerhead film holes is always arranged at the leading edge (LE), whereas cylindrical holes with compound angles or shaped holes with optimum expansion angles are used on the pressure side (PS) and suction side (SS). Notably, in the SIDO method, the configuration of shaped holes with optimal cooling performance can be directly given according to former studies [18], which is not changed in the optimization process. Also, the showerhead film cooling is conservatively designed in advance, where the modeling of the SIDO method may lead to a large error.…”

Section: Parameterizationmentioning

confidence: 99%

“…Lee and Kim [13,14] optimized a fan-shaped film hole to find the effect of geometric variations on the cooling performance. For cooling structures with more complex geometries, Chi et al studied the optimization methodology of shaped filmcooling holes [15] and the cooling system of an internally cooled vane [16] based on GA and 3-D CFD methods. Though cooling structures with favorable performance were obtained automatically, each optimization search commonly costs hundreds of CFD runs and months of time.…”

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confidence: 99%

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Semi-Inverse Design Optimization Method for Film-Cooling Arrangement of High-Pressure Turbine Vanes

Chi

Liu

Zang

2016

Journal of Propulsion and Power

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A semi-inverse design optimization method for the film-cooling arrangement of high-pressure turbine first-stage vanes is initiated based on a combinatorial optimization algorithm, a one-dimensional heat conduction model, and computational fluid dynamics methods, in which inlet temperature distortion, radiation, and inlet swirl are all considered simultaneously. This semi-inverse design optimization method can optimize the total coolant amount of the film-cooling structure while ensuring an acceptable metal temperature distribution, which finally provides a scattered and nonuniform arrangement of the film-cooling holes and a minimal coolant amount. The optimization methodology is tested on the General Electric energy-efficient engine first-stage vane under a high thermal load, and the optimization result is verified by the conjugate heat transfer computational fluid dynamics simulations. As for the optimized cooling structure, a significant improvement of cooling performance is observed while the total coolant amount is slightly reduced compared with the prototype. It is also found that neglecting each of the three factors (inlet temperature distortion, radiation, and inlet swirl) could result in a significantly different film-cooling arrangement while maintaining the overall cooling performance, which highlights the capability of the semi-inverse design optimization method at various design conditions. Nomenclature A = area of outer surface BR = blowing ratio c p = specific heat at constant pressure DR = density ratio d = thickness h = convective heat transfer coefficient k = turbulence kinetic energy/number of sample points on pressure side and suction side M = total coolant mass flow m = mass flow N = population size (of genetic algorithm) n = number of candidate holes p = pressure p = total pressure q = wall heat flux T = temperature T = total temperature Tu = turbulence intensity x = bit of the design variable α = swirl angle η = film-cooling effectiveness λ = heat conductivity ω = turbulent specific dissipation rate/rotation speed Subscripts ave = area-averaged C = child (of genetic algorithm) c = coolant/with cooling/coolant side c1 = coolant inlet 1 c2 = coolant inlet 2 f = film cooling g = hot gas in cascade passage/gas side i = vane cascade inlet max = maximum value o = rotor cascade outlet P = parent (of genetic algorithm) rad = radiative w = wall (metal beneath thermal barrier coating layer)

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Section: A Experimental Validation Of Numerical Modelmentioning

confidence: 99%

Section: Parameterizationmentioning

confidence: 99%

mentioning

confidence: 99%

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Semi-Inverse Design Optimization Method for Film-Cooling Arrangement of High-Pressure Turbine Vanes

Chi

Liu

Zang

2016

Journal of Propulsion and Power

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“…The choice of the hole exit shape is a usual problem in the study of film cooling. 15,16 In this study, we refer to the optimization method of hole shape in the film cooling and apply the method to the study of the endwall VGJs. The effect of the hole exit shape on the aerodynamic performance of the compressor cascade is discussed.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the hole exit shape of the vortex generator jets in a compressor cascade

Chen

2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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Vortex generator jets usually use a circular hole. The hole exit shape is also an important parameter, so the change of the shape will have a significant influence on the control effect of the compressor. In this article, the optimization design of the hole exit shape is studied in order to find the optimal geometry. The 2D hole exit shape is represented with a binary coded and initialized with the B-spline. The surrogate-based optimizer consists of a parametric design code, a computational fluid dynamics solver, a Kriging model, an infill sample criterion, and a genetic algorithm. First, the design of the symmetric hole is studied in a low ratio of the jet to inlet mass flow. The circumferential length of the designed hole is fixed. Second, both the symmetric hole and the asymmetric hole are studied. And the area of the hole exit shape is fixed. The results show that the optimal hole shape can enhance the strength of the jet vortex and reduce the total pressure loss of the compressor cascade. A better control effect can also be obtained in a high jet mass flow.

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“…Lee et al [13,14] optimized a fan-shaped film hole to find the effect of geometric variations on the cooling performance. For cooling structures with more complex geometries, the authors of this paper studied the optimization methodology of shaped film cooling holes [15]and cooling system of an internally-cooled vane [16] based on GA and 3D CFD methods. Though cooling structures with favorable performance were obtained automatically, each optimization search commonly costs hundreds of CFD runs and several weeks of time.…”

Section: Introductionmentioning

confidence: 99%

Semi-Inverse Design Optimization of Film Cooling Arrangement and Its Prediction of Coolant Amount of HPT Vanes

Chi

Liu

Zang

2016

JGPP

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Film cooling design is essential for modern HPT vanes. In this paper, a semi-inverse design optimization (SIDO) method for the film cooling arrangement of HPT vanes is introduced, which is based on a combinatorial optimization algorithm, a 1D heat conduction model and CFD methods. The SIDO method can optimize the total coolant amount of the film cooling structure while ensuring an acceptable metal temperature distribution. The optimization methodology was tested on a 2D vane derived from the 1st stage nozzle of a heavy-duty gas turbine, and the optimization result was validated by the conjugate heat transfer (CHT) CFD simulations. In further study, the SIDO method is applied to predict the optimal (necessary) coolant amount of the vane at various design conditions with different inlet temperature, maximal metal temperature allowed, heat conductivity of TBC, and intensity of internal/film cooling structures. The quantitive results suggested that the inlet temperature and the maximal metal temperature allowed are arbitrary to the necessary coolant amount. Improving film cooling performance is more effective to save coolant compared with internal cooling, especially at higher inlet temperature level. NOMENCLATURE c p Specific heat at constant pressure D Diameter of film hole d Thickness h Convective heat transfer coefficient k Turbulence kinetic energy / Number of sample points on PS & SS M Objective function m Mass flow N Population size (of GA) n Number of candidate holes p Pressure p * Total pressure q Wall heat flux T Temperature T * Total temperature X Streamwise distance x Bit of the design variable Y Spanwise (lateral) distance Greeks η Adiabatic film cooling effectiveness λ Heat conductivity ε Turbulent dissipation rate Subscripts ave Area-averaged c Coolant /

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Optimization of the Hole Exit Shaping of Film Holes Without and With Compound Angles for Maximal Film Cooling Effectiveness

Cited by 12 publications

References 13 publications

Semi-Inverse Design Optimization Method for Film-Cooling Arrangement of High-Pressure Turbine Vanes

Semi-Inverse Design Optimization Method for Film-Cooling Arrangement of High-Pressure Turbine Vanes

Optimization of the hole exit shape of the vortex generator jets in a compressor cascade

Semi-Inverse Design Optimization of Film Cooling Arrangement and Its Prediction of Coolant Amount of HPT Vanes

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