Combined film and impingement cooling of flat plate with reverse cooling hole

Singh, Kuldeep; Udayraj,

doi:10.1016/j.applthermaleng.2022.118224

Cited by 25 publications

(5 citation statements)

References 42 publications

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“…The liner material is also given temperature-dependent conductivity, as it varies significantly over the temperature range considered for this study [27].…”

Section: Materials Propertiesmentioning

confidence: 99%

“…The density of the fluid is calculated using the ideal gas approximation. Since there is large variation in the temperature of the fluid, the fluid properties, such as specific heat (c p ), conductivity (k), and viscosity (µ), are described as polynomials of temperature in Kelvin [27].…”

Section: Materials Propertiesmentioning

confidence: 99%

“…At a higher blowing ratio, coolant lift-off is promoted due to kidney vortices and further causes poor coolant coverage [2]. Previous works on combined film and impingement cooling demonstrate [27] that films that are assisted with jet impingement cooling have a significant improvement in cooling performance (i.e., effectiveness); therefore, the thermal protection of the component can be ensured even at a low blowing ratio (i.e., less than one). For safe operation, the component's temperature must be significantly lower than the melting temperature.…”

Section: Effect Of Film and Impingement Cooling And Blowing Ratio On ...mentioning

confidence: 99%

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Experimental and Numerical Study on the Combined Jet Impingement and Film Cooling of an Aero-Engine Afterburner Section

2023

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The recent advancement of cooling methodologies for critical components such as turbine blades, combustor liners, and afterburner liners has led to the development of a combination of impingement and film cooling. The present study proposes an efficient cooling technique for a modern aero-engine afterburner liner based on the combination of jet impingement and film cooling. To achieve this, a numerical model is devised to model the film flow over a corrugated liner with several jets impinging over it. The numerical model is validated in a set of in-house experiments as well as against experimental data available in the literature. The experiment is performed for a limited temperature range (i.e., with a low-density ratio). However, the numerical simulations are carried out by varying the blowing ratio from 0.3 to 0.6. The density ratio during the simulations is kept at 3.5. The minimum distance between the impinging plate and the liner is kept at h/D = 1. A detailed analysis of the numerical results indicates a significant drop in the temperature distribution over the liner surface because of the employed cooling technique. The present study also reveals that, under similar operating conditions, the combined jet impingement and film cooling system has the ability to achieve the targeted cooling effect at a lower bleed air flow rate due to its higher effectiveness than that of the standard film cooling arrangement.

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“…The liner material is also given temperature-dependent conductivity, as it varies significantly over the temperature range considered for this study [27].…”

Section: Materials Propertiesmentioning

confidence: 99%

Section: Materials Propertiesmentioning

confidence: 99%

Section: Effect Of Film and Impingement Cooling And Blowing Ratio On ...mentioning

confidence: 99%

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Experimental and Numerical Study on the Combined Jet Impingement and Film Cooling of an Aero-Engine Afterburner Section

2023

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“…Since the cooling efficiency can be jointly affected by both internal impingement cooling and external effusion cooling, the influence of geometric parameters on the cooling performance is more complicated. The effects of the relative hole arrangements [7,8], hole numbers [9], hole diameter [10], hole pitch [11] of impingement and film holes, and inclination angle [12][13][14] of film holes has been studied previously. The inclination angle of film holes received more attention in previous studies because the film holes directly determine the gas outflow [12,13], and the cooling inside the film holes also plays an important role in the overall cooling effect [14].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Effects of the Hole Inclination Angle and Blowing Ratio on the Characteristics of Cooling and Stress in an Impingement/Effusion Cooling System

Zhang

You

et al. 2023

Energies

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Due to the uneven temperature field and temperature gradient introduced by an efficient cooling structure, the analysis of the stress field is necessary. In this study, the cooling characteristics and stress characteristics such as the thermal stress and thermomechanical stress of an impingement/effusion cooling system were investigated by employing a fluid–thermal-structure coupling simulation method. The effects of film hole injection angle (30°–90°) and blowing ratio (0.5–2.0) were studied. The results showed that the film hole shape and the non-uniform temperature field introduced by the cooling structure had a great influence on the stress field distribution. With the increase in the blowing ratio, not only the overall cooling effectiveness of the cooling system increased, but the maximum thermal stress and thermomechanical stress near film holes also increased. The cases with a smaller inclination angle could provide a better cooling performance, but caused a more serious stress concentration of the film hole. However, the thermal stress difference at the leading and trailing edges of the film hole increased with a decreasing inclination angle. The cases with a = 30° and 45° showed serious thermal stress concentration near the hole’s acute region.

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“…效果的影响, 结果发现在凸曲率上的冷却效果要高于在平面和凹曲率壁面的情况. 过去有许多专家学者对超声速气膜冷却 [10][11][12][13][14][15][16][17] 进行了深入的研究. Lin 等 [13] 在不同静压比(ratio of static pressure, RSP, RSP = P c /P f 下, 其中 P c 为超声速气膜出口处的静压, P f 为自由来流静压), 通过分析下游的速度梯度变化, 揭示了RSP差异下混合过程的物理机制, 随着RSP增大, 有效冷却长度得到延长.…”

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Flow evolution of mixed layer on convex curvature wall under hypersonic conditions

Zhang,

Yi,

Liu

et al. 2024

Acta Phys. Sin.

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With the continuous upgrading of hypersonic vehicles, a new design requirement for imaging window is put forward, that is, conformal window to improve aerodynamic characteristics, which requires the supersonic cooling film and optical window to maintain the same curvature shape as the aircraft body.This paper investigates the mixed-layer flow evolution on a convex wall (CV). The flow field structure of the mixed layer is captured using a nanoparticle-based planar laser scattering technique in a Ma=6 hypersonic static wind tunnel, combined with fractal dimension to investigate the location of mixed-layer instability. Results of pressure, and impulse of compression (Ip) evolution along the flow direction were obtained using numerical simulation techniques. The results show that the total incoming pressure (P0) has a significant effect on the flow evolution of the mixed layer, and as P0 increases, the ratio of static pressure (RSP) decreases, the position of the mixed layer instability is delayed, and the flow velocity of the typical vortex structure increases. The presence of favorable gradients at the CV wall allows the pressure to drop along the flow direction, and the pressure is boosted when the supersonic air film along the tangential direction of the wall is in operating condition. However, as P0 increases, RSP decreases with it, and the lifting effect of the pressure on the CV decreases. The flow field is affected by the expansion effect of the CV, and Ip decreases along the flow direction. The supersonic air film can weaken the expansion effect on the CV and thus suppress the decrease of Ip. The change rate of Ip (ΔIp) is significantly affected by P0, in the range of bending impulse |IΦ|=0.191~3.62, ΔIp decreases from 178.67% to 12.02% when P0=0.5Mpa and ΔIp decreases from 40.38% to 5.64% when P0=1.0MPa. ΔIp decreases as |IΦ| increases, but the decrease weakens as P0 increases. The results reveal the flow evolution law of hypersonic mixed layer under the influence of convex curvature, and provide a certain reference for the shape design of hypersonic vehicle to achieve aerodynamic drag reduction and thermal protection characteristics.

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Combined film and impingement cooling of flat plate with reverse cooling hole

Cited by 25 publications

References 42 publications

Experimental and Numerical Study on the Combined Jet Impingement and Film Cooling of an Aero-Engine Afterburner Section

Experimental and Numerical Study on the Combined Jet Impingement and Film Cooling of an Aero-Engine Afterburner Section

Numerical Investigation of the Effects of the Hole Inclination Angle and Blowing Ratio on the Characteristics of Cooling and Stress in an Impingement/Effusion Cooling System

Flow evolution of mixed layer on convex curvature wall under hypersonic conditions

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