Turbulent Boundary-Layer Shock Interaction with and without Injection

Alzner, E.; Zakkay, V.

doi:10.2514/3.49979

Cited by 35 publications

(7 citation statements)

References 2 publications

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“…The effect of inlet Mach number, slot height and coolant mass fluxes were studied by Bass et al [27] and had developed correlations to predict film cooling effectiveness. The effect of shock wave of supersonic film cooling was studied by Takita and Masuya [28], Alzner and Zakkay [29], Peng and Jiang [30], and Martin et al [31]. Peng and Jiang [32] studied supersonic film cooling with a slotted wall structure in the region of a shock wave.…”

Section: Literature Reviewmentioning

confidence: 99%

Effect of injector configuration in rocket nozzle film cooling

2015

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List of symbols A injCross-sectional area of the nozzle at the coolant injection point (m 2 ) A throat Cross-sectional area of the throat of the nozzle (m 2 ) AR Area ratio (dimensionless) BR Blowing ratio (dimensionless) c p Specific heat (J kg −1 K −1 ) Hz Unit of frequency (cycles per second) hp Horse power (1 hp = 746 W) J Diffusion flux (kg m −2 s −1 ) p Static pressure (N m −2 ) r Radial coordinate (mm) Re Reynolds number (dimensionless) Sc Schmidt number (dimensionless) TuTurbulence intensity (%)Mass fraction of the component (dimensionless) Greek lettersDegree of film cooling effectiveness (dimensionless) ΔT Temperature difference between surface and ambient (K) Subscripts c CoolantAbstract Experimental and numerical investigations are carried out to analyze the effect of coolant injector configuration on overall film cooling performance in a divergent section of a rocket nozzle. Two different injector orientations are investigated: (1) shaped slots with a divergence angle of 15° (semi-divergent injector) (2) fully divergent slot (fully divergent injector). A 2-dimensional, axis-symmetric, multispecies computational model using finite volume formulation has been developed and validated against the experimental data. The experiments provided a consistent set of measurements for cooling effectiveness for different blowing ratios ranging from 3.7 to 6. Results show that the semi divergent configuration leads to higher effectiveness compared to fully divergent slot at all blowing ratios. The spatially averaged effectiveness results show that the difference between the two configurations is significant at higher blowing ratios. The increase in effectiveness was around 2 % at BR = 3.7 whereas it was around 12 % in the case of BR = 6. Numerical results show the presence of secondary flow recirculation zones near the jet exit for both the injectors. An additional recirculation zone present in the case of fully divergent injector caused an increase in mixing of the coolant and mainstream, and a reduction in film cooling performance.

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Section: Literature Reviewmentioning

confidence: 99%

Effect of injector configuration in rocket nozzle film cooling

2015

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“…Early studies on shock/cooling-film interaction mainly focused on the determination of the wall heat flux. Investigations of Alzner and Zakkay (1971), Kamath et al (1990 and Olsen et al (1990) led to different conclusions about the extent of the shock induced increase of the peak heat transfer. Juhany and Hunt (1994) concluded that the differences in the literature are related to the flow region where the shock impinges upon the cooling film.…”

Section: Mixing Layermentioning

confidence: 99%

Experimental investigation of the turbulent Schmidt number in supersonic film cooling with shock interaction

Marquardt,

Klaas,

Schröder

2019

Preprint

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The interaction of an impinging shock and a supersonic helium cooling film is investigated experimentally by high-speed particle-image velocimetry. A laminar helium jet is tangentially injected into a turbulent air freestream at a freestream Mach number Ma ∞ = 2.45. The helium cooling film is injected at a Mach number Ma i = 1.30 at a total temperature ratio T 0,i /T 0,∞ = 0.75. A deflection β = 8 • generates a shock that impinges upon the cooling film. A shock interaction case and a reference case without shock interaction are considered. The helium mass fraction fluctuations are measured and the turbulent mass flux as well as the turbulent Schmidt number are determined qualitatively. For comparison, large-eddy simulation (LES) results of a comparable flow configuration are used. The streamwise and wallnormal turbulent mass fluxes are in qualitative agreement with the LES data. The turbulent Schmidt number differs significantly from unity. Without shock interaction, the turbulent Schmidt number is in the range 0.5 ≤ Sc t ≤ 1.5 which is in agreement with the literature. With shock interaction, the turbulent Schmidt number varies dras-

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“…Heufer and Olivier [23] adopted a simple ramp model to conduct experimental and numerical studies on hypersonic film cooling. Alzner and Zakkay [24] studied the interplay between shock wave and supersonic film cooling. The research results have shown that the supersonic film can effectively suppress the heating effect of the shock wave on the incident position, which is in contrast with the case without the film.…”

Section: Introductionmentioning

confidence: 99%

Influence of Mach Number of Main Flow on Film Cooling Characteristics under Supersonic Condition

et al. 2021

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The flow and heat transfer characteristics of a film jet inclined to different supersonic situations with a varying Mach number of the main flow were numerically investigated. In supersonic situations, complicated waves are generated by the obstacle of the film jet. In this work, extra pressure is exerted onto the film jet, causing better film attachment to the wall. The strengthening of attachment decreases mixing between the main flow and film jet, causing better film cooling. We observed multi-interfacial layered structures caused by the film jet under the complicated effect of shock waves. At the interfaces of the film jet and shock waves, additional pressure is exerted on the film towards the wall. The pressure increases as the Mach number of the main flow increases and contributes to the increased adhesion of the gas film, which causes the cooling enhancement under a supersonic condition. In the vicinity of the film hole exit, a local low pressure region is formed under the influence of the supersonic main flow. An aerodynamic convergent–divergent state was formed in the film hole, devastating the state of supersonic congestion of the film hole and further enhancing the film cooling effect.

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Turbulent Boundary-Layer Shock Interaction with and without Injection

Cited by 35 publications

References 2 publications

Effect of injector configuration in rocket nozzle film cooling

Effect of injector configuration in rocket nozzle film cooling

Experimental investigation of the turbulent Schmidt number in supersonic film cooling with shock interaction

Influence of Mach Number of Main Flow on Film Cooling Characteristics under Supersonic Condition

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