Double Wall Cooling of an Effusion Plate with Cross Flow and Impingement Jet Combination Internal Cooling: Comparisons of Main Flow Contraction Ratio Effects

Click, Austin; Ritchie, David A.; Ligrani, Phillip M.; Liberatore, Federico; Patel, Rajeshriben; Ho, Yin-Hsiang

doi:10.2514/6.2019-3967

Cited by 2 publications

(3 citation statements)

References 13 publications

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“…In [12][13][14][15][16][17], a series of experiments were carried out to investigate the full-coverage effusion cooling of a combustor wall with internal impingement cooling. Tests were either performed with effusion cooling only and internal cross flow or using a second internal wall with impingement holes and a plenum feed and optional cross flow.…”

Section: Impingement Effusion Cooling Methods For Combustor Wallsmentioning

confidence: 99%

Experimental Study of Impingement Effusion-Cooled Double-Wall Combustor Liners: Thermal Analysis

2021

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A new experimental study is presented for a combustor with a double-wall cooling design. The inner wall at the hot gas side features effusion cooling with 7-7-7 laidback fan-shaped holes, and the outer wall at the cold side features an impingement hole pattern with circular holes. Data have been acquired to assess the thermal and aerodynamic behavior of the setup using a new, scaled up, engine-similar test rig. Similarity includes Reynolds, Nusselt, and Biot numbers for hot gas and coolant flow. Different geometrical setups are studied by varying the cavity height between the two walls and the relative alignment of the two hole patterns at several different blowing ratios. This article focuses on the thermal performance of the setup. The temperature data are acquired using two infrared systems on either side of the effusion wall specimen. In addition to cooling effectiveness evaluations, finite element simulations are performed, yielding the locally resolved wall heat fluxes. Results are presented for three cavity heights and two longitudinal specimen alignments. The results show that the hot gas side total cooling effectiveness can achieve values as high as 90% and is mainly influenced by the effusion coverage. Impingement cooling has a small influence on overall effectiveness, and the area of influence is mainly located upstream where effusion cooling is not built up completely. The analyzed geometric variations show a major influence on cavity flow and impingement heat transfer. Small cavities lead to constrained flow and high local Nusselt numbers, while larger cavities show more equalized Nusselt number distributions. A present misalignment shows especially high influence at small cavity heights. The largest cavity height, in general, showed a decrease in heat transfer due to reduced jet momentum.

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Section: Impingement Effusion Cooling Methods For Combustor Wallsmentioning

confidence: 99%

Experimental Study of Impingement Effusion-Cooled Double-Wall Combustor Liners: Thermal Analysis

2021

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“…Inadequate cooling for combustor liners leads to reduced life expectancy of combustor liners and can further lead to premature failures of combustor components such as melted liners as reported in literature (Ahmed et al, 2019). In order to lower the metal temperature of combustor liner to improve the longevity of the component, cooling parameters, such as the shape of cooling holes and the amount of cooling air, have been the focuses of previous studies (Goswami et al, 2004;Ahmed et al, 2019;Click et al, 2019). In addition, new materials for providing thermal barrier have been developed for improved cooling performance (Goswami et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Some unique properties of aerogels, including low thermal conductivity (k, 0.01-0.03 W/(m•K) at 300 K), low density (ρ, <0.1 g/cm 3 ), and high porosity (φ p , 75%-99%) (Yuan et al, 2012), make aerogels promising candidates for some of most extreme applications, such as laser targets (Fearon et al, 1987;Alon et al, 1995), microelectronic devices (Hrubesh & Poco, 1995;Xiao et al, 2000), magnetic nanocomposites (Casas et al, 2001), acoustic dampening elements (Cross et al, 1989;Forest et al, 2001), micro-particle capturers (Anderson and Ahrens, 1994;Horz et al, 2000), and heat insulators (Alkemper et al, 1995;Kwon et al, 2000;Moner-Girona et al, 2001;Reim et al, 2005;Bardy et al, 2007;Pacheco-Torgal et al, 2018). Most prominently, aerogels are utilized as thermal insulators in the areas of clothing, construction, aerospace, and energy due to their extremely low thermal conductivities.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation of Using Silica Aerogels as the Thermal Insulator for Combustor Liners

Pyo

Robertson

Yun

et al. 2020

J. Glob. Power Propuls. Soc.

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An experimental study was conducted for evaluating the feasibility of using silica aerogel as thermal insulator for combustor liners. Aerogels are a superior material for minimizing heat flux to the metal structure of the combustion liner due to their low thermal conductivity. In this study, a conical natural gas fired swirling-flame combustor was utilized for reproducing the combustion environment that's typical to a gas turbine combustor. The silica aerogel blanket was attached to the inner side of a perforated combustor liner. Temperature distribution on the outer side of the combustion liner was measured using a calibrated thermal infrared (IR) camera. To minimize the uncertainty in steel surface emissivity due to surface oxidation at elevated temperatures, designated areas on the metal surface were coated with a ceramic cement whose emissivity was carefully determined. To create a protective cooling film over the aerogel surface, cooling air was supplied from the back side of the perforated metal liner and was allowed to penetrate the silica aerogel blanket to be discharged to the combustor. As the combustor was operated at a fixed equivalence ratio of 0.83, cooling air flow rates were varied to evaluate the effectiveness of transpiration cooling on the aerogel blanket as various cooling flow rates. The measured evolutions of temperature distribution confirmed thermal equilibriums for every test condition with transpiration cooling. The measured temperature distribution of metal liner demonstrated superior thermal insulation of aerogel blanket under the protection of cooling film with a temperature difference as high as 1,580 K between combustion products temperature and the metal liner temperature on the back side. In addition, silica aerogel samples were examined before and after the combustion tests to understand their material degradation exposing to a typical gas turbine combustor environment using high-resolution scanning electron microscope (SEM). Test results suggest multiple degradation mechanisms to the silica aerogel blanket samples from the combustion tests. The material analysis suggests that improvements can be made to the silica aerogel blankets for a more resilient thermal insulator, for example, by replacing glass fibres in silica aerogels.

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Double Wall Cooling of an Effusion Plate with Cross Flow and Impingement Jet Combination Internal Cooling: Comparisons of Main Flow Contraction Ratio Effects

Cited by 2 publications

References 13 publications

Experimental Study of Impingement Effusion-Cooled Double-Wall Combustor Liners: Thermal Analysis

Experimental Study of Impingement Effusion-Cooled Double-Wall Combustor Liners: Thermal Analysis

Experimental Evaluation of Using Silica Aerogels as the Thermal Insulator for Combustor Liners

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