Numerical study of hypersonic surface heat flux with different air species models

Zhao, Youping; Huang, Haiming

doi:10.1016/j.actaastro.2020.01.002

Cited by 12 publications

(2 citation statements)

References 28 publications

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“…The specific steps are: (1) The material is processed into 2×4×22 mm 3 are evenly and densely distributed no matter inside or between the fiber bundles. After multiple infiltration-curing-pyrolysis cycles, the original morphology of z-direction carbon fibers is well preserved, indicating that the low-temperature and pressureless preparation method does not change the structural properties of the z-direction carbon fiber bundle of the braid instead of traditional dozens of impregnation and pyrolysis at temperatures over 1500 °C and hot-pressing sintering.…”

Section: Characterization-fracture Toughnessmentioning

confidence: 99%

Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

Cheng

Xun

et al. 2021

Preprint

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To find the optimum balance between strength and toughness, as well as acquiring reliable thermal shock resistance and oxidation resistance, has always been the most concerned topic in the discussion of ultra-high temperature ceramic composites. Herein, PyC modified 3D carbon fiber is used to reinforce ultra-high temperature ceramic. The macroscopic block composite with large size is successfully fabricated through ultra-low temperature sintering at 1300°C without pressure. The prepared PyC modified 3D Cf/ZrC-SiC composites simultaneously possess excellent physical and chemical stability under the synergistic effect of PyC interface layer and ultra-low temperature sintering without pressure. The fracture toughness is increased in magnitude to 13.05 ± 1.72 MPa∙m1/2 accompanied by reliable flexural strength of 251 ± 27 MPa. After rapid thermal shock spanning from RT to 1200°C, there is no visible surface penetrating cracks, spalling or structural fragmentation. The maximum critical temperature difference reaches 875°C, which is nearly three times higher than that of traditional monolithic ceramics. The haunting puzzle of intrinsic brittleness and low damage tolerance are resolved fundamentally. Under the protection of PyC interface layer, the carbon fibers around oxide layer and matrix remain structure intact after static oxidation at 1500°C for 30 min. The oxide layer has reliable physical and chemical stability and resist the erosion from fierce oxidizing atmosphere, ensuring the excellent oxidation resistance of the composites. In a sense, the present work provides promising universality in designability and achievement of 3D carbon fiber reinforced ceramic composites.

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Section: Characterization-fracture Toughnessmentioning

confidence: 99%

Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

Cheng

Xun

et al. 2021

Preprint

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show abstract

“…Dong et al [14] used the Dunn-Kang 5-species, 7-species, 11-species chemical reaction models and one-temperature, two-temperature thermodynamic models to solve the thermochemical nonequilibrium flow, respectively, and found that the differences between the heat flux distributions predicted by the 7-and 11-species was not significant, while the heat flux of the 5-species was smaller, with a difference up to 10% or even more; the heat fluxes calculated by different thermodynamic models are slightly different, with a maximum difference of about 10%. Zhao et al [15] compared the aerodynamic heat fluxes under the Gupta 5-, 7-, 11-species chemical reaction models and found that the wall heat fluxes under the 7-and 11-species were significantly larger than that of the 5-species when the Mach number was greater than 12, and that the 7-species model should be adopted. Dobrov et al [16] used the Gupta 5-species and Park 5-species chemical kinetic models to solve the nearly same results of the air compositions at the stagnation point of a sphere.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Thermodynamic and Chemical Kinetic Models for Hypersonic and High-Temperature Flow Simulation

Zhao,

Yang,

Wang

et al. 2023

Applied Sciences

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Significant thermochemical nonequilibrium effects always exist in the flow field around hypersonic vehicle at extreme flight condition. Previous studies have proposed various thermodynamic and chemical kinetic models to describe the thermochemical nonequilibrium processes in hypersonic and high-temperature flow. However, different selections from such models might lead to remarkable variations in computational burden and prediction accuracy, which is still a matter of being unclear. In the present study, different commonly studied models for calculating the thermochemical nonequilibrium are systematically evaluated. The 5-, 7- and 11-species chemical kinetic models of Dunn-Kang, Gupta and Park together with the one- and two-temperature models are employed respectively to simulate the hypersonic flows over a standard cylinder with the radius of 1 m by HyFLOW, which is a commercial software based on the numerical solution of Navier-Stokes equations. Three flight conditions of FIRE Ⅱ classical flight trajectory are employed in the study. It shows that the differences between the results of the Dunn-Kang, Gupta and Park chemical kinetic models with the same number of species are small, but the Gupta model predicts the most conservative values of the wall heat flux. When only the order of magnitude and distribution trends of the pressure and wall heat flux are concerned, the one-temperature model combined with 5-species chemical reaction model can be used for a rapid prediction. While the accurate flow solution is required, the two-temperature model conjugated with Gupta 11-species model is recommended, especially at the conditions of extremely high altitude and Mach number.

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Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

Cheng

Xun

et al. 2021

J Adv Ceram

View full text Add to dashboard Cite

Finding the optimum balance between strength and toughness, as well as acquiring reliable thermal shock resistance and oxidation resistance, has always been the most concerned topic in the discussion of ultra-high temperature ceramic composites. Herein, PyC modified 3D carbon fiber is used to reinforce ultra-high temperature ceramic (UHTC). The macroscopic block composite with large size is successfully fabricated through low temperature sintering at 1300 °C without pressure. The prepared PyC modified 3D Cf/ZrC-SiC composites simultaneously possess excellent physical and chemical stability under the synergistic effect of PyC interface layer and low temperature sintering without pressure. The fracture toughness is increased in magnitude to 13.05 ± 1.72 MPa·m1/2 accompanied by reliable flexural strength of 251 ± 27 MPa. After rapid thermal shock spanning from room temperature (RT) to 1200 °C, there are no visible surface penetrating cracks, spalling, or structural fragmentation. The maximum critical temperature difference reaches 875 °C, which is nearly three times higher than that of traditional monolithic ceramics. The haunting puzzle of intrinsic brittleness and low damage tolerance are resolved fundamentally. Under the protection of PyC interface layer, the carbon fibers around oxide layer and matrix remain structure intact after static oxidation at 1500 °C for 30 min. The oxide layer has reliable physical and chemical stability and resists the erosion from fierce oxidizing atmosphere, ensuring the excellent oxidation resistance of the composites. In a sense, the present work provides promising universality in designability and achievement of 3D carbon fiber reinforced ceramic composites.

show abstract

Numerical study of hypersonic surface heat flux with different air species models

Cited by 12 publications

References 28 publications

Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

Evaluation of Thermodynamic and Chemical Kinetic Models for Hypersonic and High-Temperature Flow Simulation

Using PyC modified 3D carbon fiber to reinforce UHTC under low temperature sintering without pressure

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