Effect of blockage configuration on film cooling with and without mist injection

Tian, Ke; Wang, Jin; Liu, Chao; Yang, Li; Sundén, Bengt

doi:10.1016/j.energy.2018.04.050

Cited by 26 publications

(2 citation statements)

References 15 publications

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“…Inlet temperature of gas turbine above 1800 K is exceeding melting temperature of blade materials (about 1500 K) [1]. Growth rate of inlet temperature for gas turbines is significantly higher than development rate of temperature-resistant materials [2].…”

Section: Introductionmentioning

confidence: 98%

Effect of dielectric barrier discharge plasma on film cooling performance

et al. 2022

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To improve film cooling effectiveness of a gas turbine blade, a kind of plasma actuator is introduced on the blade surface. The effect of three arrangements of plasma actuators on flow characteristics and film cooling performance is numerically investigated by a verified turbulence model. Results show that the coolant air under plasma is pulled down to the wall, and the near-wall air is sped up to promote the film cooling effectiveness downstream the wall. It is discovered that the plasma actuators near the film hole show weaker aerodynamic actuation than that downstream the wall. Compared with the plasma actuators off case, the maximum improvement in the wall-averaged film cooling effectiveness of the case with up plasma actuators is 11.7% under low blowing ratios. The wall-averaged film cooling effectivenesses of the cases with down plasma actuators and up-down plasma actuators increase by 138.3% and 122.9% under the blowing ratio of 1.5.. Vortex structures are broken up, and vortex is separated by two jets induced by aerodynamic actuation. The maximum wall pressure difference reaches 1.89% when plasma actuator is arranged downstream the wall.

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Section: Introductionmentioning

confidence: 98%

Effect of dielectric barrier discharge plasma on film cooling performance

et al. 2022

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“…For mist injection cases, deposition located at a distance 5d ("d" is the diameter of the coolant hole) from the coolant hole showed an improvement in performance downstream of the deposition location. Tian et al (2018) studied the effect of blockage configuration in the coolant passage on the film cooling with and without mist injection. It was found that the presence of hemispherical blockage has resulted in lesser cooling effectiveness compared to tetrahedral blockage.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of mist-air film cooling on a 3-D flat plate

M.V.V.

Surya²,

Singh³

et al. 2022

HFF

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Purpose The purpose of this study is to explore the mist-air film cooling performance on a three-dimensional (3-D) flat plate. In mist-air film cooling technique, a small amount of water droplets is injected along with the coolant air. The objective is to study the influence of shape of the coolant hole and operating conditions on the cooling effectiveness. Design/methodology/approach In this study, 3-D numerical simulations are performed. To simulate the mist-air film cooling over a flat plate, air is considered as a continuous phase and mist is considered as a discrete phase. Turbulence in the flow is accounted using Reynolds averaged Navier–Stokes equation and is modeled using k–e model with enhanced wall treatment. Findings The results of this study show that, for cylindrical coolant hole, coolant with 5% mist concentration is not effective for mainstream temperatures above 600 K, whereas for fan-shaped hole, even 2% mist concentration has shown significant impact on cooling effectiveness for temperatures up to 1,000 K. For given mist-air coolant flow conditions, different trend in effectiveness is observed for cylindrical and fan-shaped coolant hole with respect to main stream temperature. Research limitations/implications This study is limited to a flat plate geometry with single coolant hole. Practical implications The motivation of this study comes from the requirement of high efficiency cooling techniques for cooling of gas turbine blades. This study aims to study the performance of mist-air film cooling at different geometric and operating conditions. Originality/value The originality of this study lies in studying the effect of parameters such as mist concentration, droplet size and blowing ratio on cooling performance, particularly at high mainstream temperatures. In addition, a systematic performance comparison is presented between the cylindrical and fan-shaped cooling hole geometries.

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