Experimental investigation of geometrical effect on flow and heat transfer performance of lamilloy cooling structure

Zhang, Bo; Lin, Libing; Zhang, Naru; Xue, Shuangsong; Ji, Honghu

doi:10.2298/tsci190528071z

Cited by 6 publications

(3 citation statements)

References 9 publications

(9 reference statements)

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“…All in all, many studies have been conducted to investigate the effects of hole shape and hole inclination angle on the film cooling performance [23][24][25]. However, few efforts were devoted to reveal the influence of the forward expansion angle of the shaped hole on the flow and cooling characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effect of forward expansion angle on film cooling characteristics of shaped holes

Zhang

Lin

et al. 2020

Open Physics

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According to the design requirements of high-temperature combustion chamber, an advanced shaped hole structure was designed for film cooling. Numerical method was applied in this study to investigate the flow and heat transfer characteristics of shaped holes and compared with those of cylindrical holes. The influence of the forward expansion angle of shaped holes on the flow and heat transfer was studied. The results show that compared to cylindrical holes, the diffused structure of shaped holes decreases the momentum of jet flow, improves the adhesion characteristics of the cooling air film, increases the diffusion of the coolant air outflow and improves the cooling efficiency between adjacent columns of holes in the lateral direction. When the forward expansion angle increases, the expansion section induced the flow vortex, which reduces the radial velocity of coolant flow and enhances the diffusion of cooling air film both in streamwise and spanwise directions. However, as the forward expansion angle increases further, the scale of vortex inside the shaped hole grows. Too large vortex inside the shaped hole increases the coolant eject angle, which weakens the film covering effect. Additionally, the shaped hole results in an increase in lateral spreading and enhances the cooling effect between adjacent columns of the film hole. The enhancement of the film cooling characteristics is due to the change in the shape of the film hole, resulting in the enhancement of the flow vortex, which induces complicated secondary flow.

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Section: Introductionmentioning

confidence: 99%

Effect of forward expansion angle on film cooling characteristics of shaped holes

Zhang

Lin

et al. 2020

Open Physics

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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]. As one of the most common and effective external cooling methods, film cooling was used to avoid damages of components in advanced gas turbines by gas in high temperature [3].…”

Section: Introductionmentioning

confidence: 99%

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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“…Wang chunhua et al [22] investigated the flow-filed from converging-slot and fan shaped hole numerically adopting LES method. Bo Zhang et al [23] experimentally investigated the influence of lamilloy cooling structure on flow and heat transfer characteristics [24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

The Heat Transfer Characteristics in Stepped Hole of Traditional Metal Materials Induced by Stepped Film Holes

Libing¹,

Zhang²,

Li³

et al. 2020

Rev. Chim.

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With the increase of temperature requirement, the application of metal matrix materials is gradually reduced due to its poor temperature resistance. In order to improve the application of traditional metal based materials, new cooling technology must be developed to meet the application of metal based materials. In this paper, the cooling flow field of cylindrical hole and two kinds of stepped film holes based on metal materials is simulated by large eddy method(LES), the development of vortex structure and flow characteristics in the mixing area of coolant flow and mainstream are analyzed and studied. The distribution is strongly effected by stronger thermal convection compared with the new temperature resistant material. The results show that four kinds of vortices form downstream the film hole, namely, horseshoes vortex, shear layer vortex, hairpin vortex and the counter rotate vortex pair (CVP). The CVRP formed on the stepped plane which strongly influences the flow and heat transfer of downstream, which is more evident in metal based materials, especially resulted by its isotropic features. Compared with the cylindrical film hole, the structure of step plane efficiently decreases the coolant flow velocity which results in a decrease of the CVP intensity so that the cooling film is adherent to the wall. The thermal conductivity of metal base material is strong, which has a great influence on the temperature distribution inside the wall. Velocity pulsation tightly influenced by CVP, in where the CVP intensity is strong, velocity pulsation is also strong so that the coolant flow strongly mixes with the mainstream. The flow velocity and velocity pulsation decrease with the increasing of the area ratio of stepped hole. The influence of geometric parameters on the heat transfer performance is mainly due to the high heat transfer performance of the metal matrix material.

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Experimental investigation of geometrical effect on flow and heat transfer performance of lamilloy cooling structure

Cited by 6 publications

References 9 publications

Effect of forward expansion angle on film cooling characteristics of shaped holes

Effect of forward expansion angle on film cooling characteristics of shaped holes

Effect of dielectric barrier discharge plasma on film cooling performance

The Heat Transfer Characteristics in Stepped Hole of Traditional Metal Materials Induced by Stepped Film Holes

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