Blade Tip Shape Optimization for Enhanced Turbine Aerothermal Performance

Maesschalck, C. De; Lavagnoli, Sergio; Paniagua, Guillermo

doi:10.1115/1.4025202

Cited by 34 publications

(9 citation statements)

References 20 publications

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“…The genetic optimizer CADO [24,25,26,27] was used in this work and is a differential evolution multi-objective optimization tool. The two selected optimization objectives were minimum mass flow averaged outflow entropy and maximum shaft power.…”

Section: Optimization Proceduresmentioning

confidence: 99%

Design, Optimization, and Analysis of Supersonic Radial Turbines

Inhestern

Braun

Paniagua

et al. 2020

Journal of Engineering for Gas Turbines and Power

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New compact engine architectures such as pressure gain combustion require ad hoc turbomachinery to ensure an adequate range of operation with high performance. A critical factor for supersonic turbines is to ensure the starting of the flow passages, which limits the flow turning and airfoil thickness. Radial outflow turbines inherently increase the cross section along the flow path, which holds great potential for high turning of supersonic flow with a low stage number and guarantees a compact design. First, the preliminary design space is described. Afterward a differential evolution multi-objective optimization with 12 geometrical design parameters is deducted. With the design tool autoblade 10.1, 768 geometries were generated and hub, shroud, and blade camber line were designed by means of Bezier curves. Outlet radius, passage height, and axial location of the outlet were design variables as well. Structured meshes with around 3.7 × 106 cells per passage were generated. Steady three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) simulations, enclosed by the k-omega shear stress transport turbulence model were solved by the commercial solver CFD++. The geometry was optimized toward low entropy and high-power output. To prove the functionality of the new turbine concept and optimization, a full wheel unsteady RANS simulation of the optimized geometry exposed to a nozzled rotating detonation combustor (RDC) has been performed and the advantageous flow patterns of the optimization were also observed during transient operation.

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Section: Optimization Proceduresmentioning

confidence: 99%

Design, Optimization, and Analysis of Supersonic Radial Turbines

Inhestern

Braun

Paniagua

et al. 2020

Journal of Engineering for Gas Turbines and Power

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“…11,12 It has found that the shape of blade tip has some relation with the leakage flow characteristics in the tip region of turbine rotors, 13 and some different types of winglets were designed and surrounded blade tip section to improve the tip flow structures of turbine blades, such as the winglets with tip overhang, with cavity, and with shaped features. 14 Based on the studies of tip winglet in turbine blades, it is noted that both the driving pressure difference near the blade tip and the leakage coefficient seem to be changed due to the winglet, which attributes to reduction of the strength of leakage flow and additional losses in the tip gap of rotors. 10,11,15 When the tip platform extension is used in turbine rotors or cascades, the winglet around the pressure side benefits to reduce the discharge coefficient of leakage flow and the pressure difference across the tip gap, and it eventually produces higher losses in the tip region, while the suction-side winglet produces fewer losses in comparison with the baseline.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of blade tip winglet on flow structure in a high loading transonic rotor

Zhao

Cui

Xiang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The interactions of tip leakage flow with mainstream and shock wave result in larger aerodynamic losses and blockage in high loading compressors and tend to be one of the triggers for flow instability. In order to attenuate the influence of leakage flow and improve the stall margin of highly loaded compressor, the new rotors surrounded by tip winglet are investigated by a numerical method. The tip winglet is designed by extending the flat blade tip section in outer 1.5% span of rotor blade. As the angle between the leakage flow and main flow decreases due to winglet, the losses and flow blockage have been weakened near stall condition, and the stall margin of new rotor with pressure-side winglet has an increase of over 10%. The migration and accumulation of low-energy fluids near the corner of casing endwall are affected significantly by tip winglet. As a result, the pressure-side winglet causes an increase of static pressure near the casing corner of pressure surface. Although the driving pressure difference near the leading edge of blade has increased slightly in the tip region, the strength and massflow rate of leakage flow appear to be decreased. As the leakage flow weakens in the new rotor with pressure-side winglet, its interaction with mainstream and shock has been suppressed obviously, and the delay of rotating stall occurs as well. Moreover, the flowfields of the new rotor with pressure-side winglet have been simulated at 40%, 60%, and 80% design speed. It is shown that the flow blockage and losses in the tip region have also reduced near stall point, and an improvement of overall performance is present in the new rotor with pressure-side winglet. All the changes of tip flow structure caused by winglet benefit to an increase of aerodynamic performance of new rotor at full rotational speed range.

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“…The results have shown that the overall HTC on the squealer tip is higher than that near the PS and SS, and it is lower than that on the flat tip. De Maesschalck et al . (2014) presented a novel optimization of rotor tip profiles and found that the reduction of thermal load of the optimized tip shaper can be up to 40 percent, compared to the flat tip geometry.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of high pressure turbine blade tip-shaping effects on the aerothermal and dynamic performance

Tong¹,

Gou²,

Li³

et al. 2019

MMMS

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Purpose In order to improve the engine reliability and efficiency, an effective way is to reform the turbine blade tip conformation. The paper aims to discuss this issue. Design/methodology/approach The present research provides several novel tip-shaping structures, which are considered to control the blade tip loss. Four different tip geometries have been studied: flat tip, squealer tip, flat tip with streamwise ribs and squealer tip with streamwise ribs. The tip heat transfer and leakage flow are both analyzed in detail, for example the tip heat transfer coefficient, tip flow and local pressure distributions. Findings The results show that the squealer seal and streamwise rib can reduce the tip heat transfer and leakage loss, especially for the squealer tip with streamwise ribs. The tip and near-tip flow patterns at the different locations of axial chord reflect that both the squealer seal and streamwise rib structure can control the tip leakage flow loss. In addition, the analysis of the aerodynamic parameters (the static pressure and turbine efficiency) also indicates that the squealer tip with streamwise ribs obtains the highest adiabatic efficiency with an increase of 2.34 percent, compared with that of the flat tip case. Originality/value The analysis of aerothermal and dynamic performance can provide a reference for the blade tip design and treatment.

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Blade Tip Shape Optimization for Enhanced Turbine Aerothermal Performance

Cited by 34 publications

References 20 publications

Design, Optimization, and Analysis of Supersonic Radial Turbines

Design, Optimization, and Analysis of Supersonic Radial Turbines

Numerical investigation of blade tip winglet on flow structure in a high loading transonic rotor

Numerical investigation of high pressure turbine blade tip-shaping effects on the aerothermal and dynamic performance

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