Numerical assessment of round-to-slot film cooling performances on a turbine blade under engine representative conditions

Xingdan, Zhu; Zhang, Jingzhou; Tan, Xiao

doi:10.1016/j.icheatmasstransfer.2018.12.008

Cited by 43 publications

(7 citation statements)

References 37 publications

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“…They numerically compared the adiabatic EFC efficiency of the cylindrical film holes and fan-shaped film holes. Zhu et al [16] numerically compared the showerhead EFC performance of the cylindrical film hole, fan-shaped film hole and the converging round-to-slot film hole in the blade leading edge (BLE). Ye et al [17,18] introduced the groove structure into the showerhead film hole on the BLE to optimize the EFC effectiveness.…”

Section: Nomenclature Cmentioning

confidence: 99%

Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

Wang,

Ng,

et al. 2023

FHMT

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The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling, such as the impingement cooling and the axial flow cooling. This asymmetrical property will affect the cooling performance in the blade leading edge, whereas such effects are not found in most of the studies on vortex cooling due to the neglect of the mainstream flow in the airfoil channel. This study involves the mainstream flow field and the rotational effects based on the profile of the GE E 3 blade to reveal the mechanism of the asymmetrical flow structure effects. The nozzle position on the characteristics of the vortex and film composite cooling in the turbine rotating blade leading edge is numerically investigated. The cool-ant injecting nozzles are set at the side of the pressure surface (PS-side-in) vs. that is set at the side of the suction surface (SS-side-in) to compare the cooling characteristics at the rotating speed range of 0-4000 rpm with fluid and thermal conjugate approach. Results show that the nozzle position presents different influences under low and higher rotational speeds. As for the mainstream flow, rotation makes the stagnation line move from the pressure surface side to the suction surface side, which changes the coolant film attachment on the blade leading edge surface. The position of nozzles, however, indicates limited influence on the coolant film flow. As for the internal channel vortex flow characteristics, the coolant injected from the nozzles forms a high-velocity region near the target wall, which brings about enhancing convective heat transfer. The flow direction of the vortex flow near the internal channel wall is opposite and aligns with the direction of Coriolis force in both the PS-side-in and SS-side-in, respectively. Therefore, the Coriolis force augments the convective heat transfer intensity of the vortex cooling in the internal channel in SS-side-in while weakening the internal heat transfer in PS-side-in. Such effects become more intense with higher rotational speed. The blade surface temperature decreases as the Coriolis force increases the internal heat transfer intensity. The SS-side-in suggests a superior composite cooling performance under the relatively higher rotating speed. The SSside-in structure is recommended in the gas turbine blade leading edge running at a higher rotating speed. KEYWORDSVortex cooling; injecting nozzle location; gas turbine; blade film cooling Abbreviation BLE Blade leading edge IVC Internal vortex cooling EFC External film cooling delta Area-averaged dimensionless temperature θ on the blade surface VFCC Vortex and film composite cooling GCI Grid Convergence Index MF Mainstream flow SST∼γ -θ SST k-ω with γ -θ transition model SST SST k-ω model SL Stagnation line

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Section: Nomenclature Cmentioning

confidence: 99%

Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

Wang,

Ng,

et al. 2023

FHMT

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“…As is known to all, film cooling technology avoids direct contact of hot gas with the turbine blade surface by injecting a layer of coolant along the surface [1]. Compared to the fan-shaped hole [2], Y-shaped hole [3], counter-inclined hole [4], and round-to-slot hole [5], the trenched hole can be formed by cutting the thermal barrier coating, thus avoiding the complicated machining of the blade metal. For the transverse trench, the depth and width of it have a significant impact on the film cooling effectiveness (FCE) [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of mist/air film cooling performance of trenched holes with shaped lips

et al. 2023

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Mist-assisted film cooling has exhibited great potential for efficient cooling of a turbine blade. Trench structures can significantly affect the film cooling performance of air, while their impact on the adhesion characteristics of the droplets and thus the mist-assisted film cooling performance is unclear. This work highlights the combination of these two aspects by exploring the improvement of the mist-assisted film cooling performance for trenched holes with shaped lips using three-dimensional computations. The results show that the upper lip structure plays a significant role in the adiabatic film cooling effectiveness, whereas the lower lip structure has little effect on it. It is found that the effect of upper lip structure on the adiabatic film cooling effectiveness increases with increasing blowing ratio; the Coanda effect makes the droplets more attached to the wall of the upper fillet lip structure and upper bevel lip structure. Meanwhile, the concentration of mist and the diameter of droplets are crucial for significantly improving the adiabatic film cooling effectiveness. In general, better adiabatic film cooling effectiveness values are observed for both 10 ?m diameter droplets at a specified concentration of mist and larger concentration of mist at a specified droplet size. This work proposes a novel and efficient means of enhancing the cooling performance using mist/air mixture and trenched holes with shaped lips.

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“…At present, studies on the shallow trenched-hole film cooling are mostly performed on flat plates. While in actual turbine cascade channel, film cooling is applied in a highly complex condition influenced by multiple factors such as surface curvature, pressure gradient [27][28][29]. Therefore, the application shallow trenched-hole cooling structure in actual turbine blades needs further investigation.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Shallow Trenched-Hole Film Cooling Effectiveness at Turbine Blade Pressure Side

Yin¹,

Huang

Huang³

2023

J. Phys.: Conf. Ser.

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Numerical simulations are performed to investigate the effects of shallow trenches on the adiabatic film cooling effectiveness (ηad) of single row film cooling on the pressure side of a turbine guide vane, under the cascade representative conditions. The mainstream inlet Reynolds number is set as 4×105. A single row of film cooling holes are located at 30% axial chord length at the pressure side. Three shallow trenches with different widths (w/d=2, 2.5 and 3) but have the same depth (0.75d) and a cylindrical film cooling hole are compared in the current study at M= 2.0. The results show that the shallow trenched-hole on the pressure side significantly suppresses lift-off of the secondary flow, and effectively improves the spanwise uniformity of film coverage. Therefore, compared with the conventional cylindrical hole (CH), the shallow trenched-hole shows a significant enhanced film cooling performance at M=2.0. By comparisons, it is confirmed that the shallow trenches with w/d=2 and 2.5 are more pronounced than the shallow trench with w/d=3. While the shallow trench with w/d=2.5 takes a little advantage over the w/d=2.

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Numerical assessment of round-to-slot film cooling performances on a turbine blade under engine representative conditions

Cited by 43 publications

References 37 publications

Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

Analysis of mist/air film cooling performance of trenched holes with shaped lips

Investigation on Shallow Trenched-Hole Film Cooling Effectiveness at Turbine Blade Pressure Side

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