Gas Turbine Heat Transfer and Cooling Technology

Han, Je-Chin; Dutta, S.; Ekkad, Srinath V.

doi:10.1201/b13616

Cited by 599 publications

(357 citation statements)

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“…Increasing the gas temperature at turbine inlet is one of the important ways to improve the performance of gas-turbines (Han et al, 2000). At the present time, the inlet temperature of most turbines exceeds the acceptable temperature of the vane/blade material, and thus external film-cooling and internal rib-roughed convective and/or impingement cooling have to be applied to assure the turbine safety and durability.…”

Section: Introductionmentioning

confidence: 99%

Multi-field coupling analysis on the film-cooling with transverse and arched trenches

Wang

Zhang

et al. 2019

JTST

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In this study, the properties of the flat-plate film-cooling with transverse and arched trenches are investigated. The conjugate temperature field and thermal stress field were both predicted by the multi-field coupling method. In addition, the transverse trench configuration was investigated and compared as the benchmark case. The results show that the blockage effect formed by the arched trench is helpful to improve the coolant lateral coverage and thus the cooling performance. Meanwhile, the thermal stress concentration may be stronger due to the higher temperature gradient for the arched trench configuration. The distance between the downstream trench edges and the holes is of great importance to the cooling performance. The closer this distance, the more conductive to the blockage effect and the lateral coverage, which is helpful to improve the cooling performance. The distance between the upstream trench edges and the holes shows less impact on the cooling performance. Compared with the non-trench film cooling, the trenched models can form higher temperature gradient, so the thermal expansion near the film hole is more different from that in other region, which tend to form stronger stress concentration near the film hole. Compared with the transverse trench, the arched trench can deliver the coolant jet from the center line to the lateral side, which is helpful to form laterally coverage in the downstream region, especially under the higher blowing ratio. So the arched trench can form lower temperature gradient and relative uniform thermal expansion, which is helpful to decrease the stress concentration around the cooling hole.

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Section: Introductionmentioning

confidence: 99%

Multi-field coupling analysis on the film-cooling with transverse and arched trenches

Wang

Zhang

et al. 2019

JTST

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“…A large thermal stress is usually caused by the temperature gradient through the thickness direction due to the using of an internal air-cooling system in the blades [3][4][5]. The stress causes surface recrystallization, thermal barrier coating (TBC) separation, and fatigue crack nucleation that are detrimental to the blades [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Investigations into the Surface Strain/Stress State in a Single-Crystal Superalloy via XRD Characterization

Duan

Pei

et al. 2018

Metals

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Abstract:The present study was aimed at determining the surface strain/stress state in an Ni-based single-crystal (SC) superalloy that was subjected to two different cooling rates from solid solution temperature through using the X-ray diffraction (XRD) method. The normal stresses σ s 11 and σ s 22were determined, then the Von Mises stresses (σ s V M ) were derived from them. Field emission gun scanning electron microscope (FEG-SEM) and transmission electron microscope (TEM) micrographs were taken to illustrate the strain/stress state change. The precipitation of the secondary γ phases in the γ phase and the formation of the dislocation in the interphase upon a slower cooling rate caused the γ phase lattice distortion to increase, so a larger σ s V M of the γ phase was realized in comparison to the faster cooling sample. For both of the two cooling modes, we found that the σ s V M of the γ phase increased due to the growth of the γ phase during the aging process. Also, the aging process led to pronouncedly anisotropic lattice mismatches in the {331} and {004} planes. In addition, the surface strain/stress states of a cylinder sample and a tetragonal sample were also studied using a faster cooling rate, and σ s 11 and σ s 22 were analyzed to explain the influence of the shape factor on the stress anisotropy in the [001] and 110 orientations. The strain in the [001] orientation of the γ phase is more sensitive to the shape change.

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“…Rotor inlet temperatures are on the order of 1500°C, and it is estimated that a metal temperature increase of only 25°C can reduce part life to half of its design value (Han, et al. [1]); therefore, advanced reliable cooling schemes are necessary. A particularly challenging region to cool is the hub region of a turbine blade, also known as an endwall.…”

Section: Introductionmentioning

confidence: 99%

Endwall Heat Transfer for a Turbine Blade With an Upstream Cavity and Rim Seal Leakage

Lynch

Thole

Kohli

et al. 2013

Volume 3C: Heat Transfer

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Aerodynamic loss and endwall heat transfer for a turbine blade are influenced by complex vortical flows that are generated at the airfoil-endwall junction. In an engine, those flows interact with clearance gaps between stationary and rotating components, as well as with leakage flow that is designed to exhaust through the gaps. This paper describes experimental measurements of endwall heat transfer for a highpressure turbine blade with an endwall overlap geometry, as well as an upstream leakage feature that supplied swirled or unswirled leakage relative to the blade. For unswirled leakage, increasing its mass flow increased the magnitude and pitchwise uniformity of the heat transfer coefficient upstream of the blades although heat transfer further into the passage was unchanged. Leakage flow with swirl shifted the horseshoe vortex in the direction of swirl and increased heat transfer on the upstream blade endwall, as compared to unswirled leakage. For a nominal leakage mass flow ratio of 0.75%, swirled leakage did not increase area-averaged heat transfer relative to unswirled leakage. At a mass flow ratio of 1.0%, however, swirled leakage increased overall heat transfer by 4% due to an increase in the strength of the vortical flows.

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Gas Turbine Heat Transfer and Cooling Technology

Cited by 599 publications

References 0 publications

Multi-field coupling analysis on the film-cooling with transverse and arched trenches

Multi-field coupling analysis on the film-cooling with transverse and arched trenches

Investigations into the Surface Strain/Stress State in a Single-Crystal Superalloy via XRD Characterization

Endwall Heat Transfer for a Turbine Blade With an Upstream Cavity and Rim Seal Leakage

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