Simulation of Sharp Leading Edge Aerothermodynamics

Boyd, Iain D.; Padilla, Jose F.

doi:10.2514/6.2003-7062

Cited by 12 publications

(6 citation statements)

References 17 publications

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“…MONACO is a general 2D/3D, parallel, unstructured mesh DSMC code that has been applied to many hypersonic, rarefied flows. 11,12 All MONACO solutions are generated using a fixed wall temperature at 500 K. Bird's variable hard sphere model is used. 2 In general, the mesh used for the final solution for each case is adapted from previous solutions such that each cell size is on the order of a mean free path.…”

Section: Background and Simulation Proceduresmentioning

confidence: 99%

Effects of Continuum Breakdown on Hypersonic Aerothermodynamics

Lofthouse

Boyd

Wright

2006

44th AIAA Aerospace Sciences Meeting and Exhibit

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Hypersonic vehicles experience different flow regimes during flight due to changes in atmospheric density. Hybrid Computational Fluid Dynamics (CFD) and Direct Simulation Monte Carlo (DSMC) methods are developed to simulate the flow in different hypersonic regimes. These methods use a breakdown parameter to determine regions of the flow where the CFD physics are no longer valid. The current study investigates the effect of continuum breakdown on surface properties, such as pressure, shear stress and heat transfer rate, on a cylinder in a Mach 10 flow of argon gas for several different flow regimes, from the continuum to a rarefied gas. The difference in total drag ranges from 0.5% for a continuum to 26.2% for a rarefied gas. Peak heat transfer rate differences ranges from nearly 4% for a continuum to almost 32% for a rarefied gas. Drag depends primarily on continuum breakdown in the wake, while heat transfer rate appears to depend primarily on continuum breakdown in the shock and differences in thermal boundary layer thickness. I. Introduction A hypersonic vehicle such as a planetary entry capsule or a reusable launch vehicle, will experience vastly different flow regimes during the course of its flight trajectory because the earth's atmosphere varies in density as a function of altitude. Reproduction of these varied flow conditions in ground-based laboratory facilities is both expensive and technically challenging. Hence, there is an extremely important role for computational models in the development of hypersonic vehicles.

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Section: Background and Simulation Proceduresmentioning

confidence: 99%

Effects of Continuum Breakdown on Hypersonic Aerothermodynamics

Lofthouse

Boyd

Wright

2006

44th AIAA Aerospace Sciences Meeting and Exhibit

Self Cite

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“…Reusable atmospheric reentry vehicles and hypersonic fl ight vehicles, regardless of their specifi c designs, require control surface with sharp leading edges (radius as low as 1 cm or less) in order to increase the range of hypersonic fl ight paths and reentry trajectories (Boyd and Padilla 2003;Loehman et al 2006;Sziroczak and Smith 2016). However, low-radius edges are subject to much greater aerothermal heating than blunt edges, such as those of the space shuttle.…”

Section: Introductionmentioning

confidence: 99%

Effect of ZrB2 Particle Size on Pressureless Sintering of ZrB2 - ß-Sic Composites

Rocha¹,

Sene²,

JULIANI

et al. 2019

J.Aerosp. Technol. Manag.

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Zirconium diboride is an ultra high temperature ceramic material that leads this emerging class of materials because of its distinct combination of properties, including high melting temperature (> 3000 °C) and the lowest theoretical density (6.09 g·cm-3) among the borides. This combination of properties makes ZrB2 candidate for airframe leading edges on sharp-bodied reentry vehicles. In this work, the effect of particle size of ZrB2 on the pressureless sintering of ZrB2-SiC composites was studied, using ZrB2 powder with average particle size of 2.6 and 14.2µm. Four different vol% concentration of ß-SiC (0, 10, 20 and 30 vol%) were added to as-received and planetary milled ZrB2 powder. Samples were pressureless sintered at 2050 °C/1h in argon atmosphere. The reduction of initial ZrB2 particle size led to composites with better results of densification, mechanical properties and oxidation resistance regardless ß-SiC addition, showing relative densities around 92.5 %Theoretical Density (Td) and flexural strength and microhardness around 260 MPa and 17.5 GPa, respectively. Composites processed with as-received ZrB2 powder showed increasing in densification and flexural strength with the SiC content increasing. Relative density varied from 74.7 to 90.8 %TD and flexural strength from 102 to 241 MPa, for 0 and 30 vol% of SiC, respectively.

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“…Continuous increase of flight Mach number of the hypersonic vehicle, the total temperature of the freestream increases and the surface aerodynamic heating of the aircraft is furtherly enhanced. To meet the aerodynamic performance, the sharp leading edge shape is adopted, which also leads to strong aerodynamic heating (Boyd & Padilla, 2003;Glass, 2008). The peak of heat flux density at the leading edge of a hypersonic vehicle can reach more than 10 MW/m 2 (Kennedy et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Effects of Coolants of Double Layer Transpiration Cooling System in the Leading Edge of a Hypersonic Vehicle

et al. 2021

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As a promising and efficient active cooling method, double layer transpiration cooling is introduced into the design of the cooling system in the leading edge of a hypersonic vehicle. The physical model is built combined with hypersonic transpiration cooling, film cooling, heat conduction, porous media heat conduction and convection heat transfer. In addition, effects of different kinds of coolants are considered to reveal cooling mechanisms in different operation conditions. A comprehensive turbulence model validation and mesh independence study are provided. Flow characteristics caused by flow impingement, separation, transition and interaction with the cooling flows are displayed and analyzed in the work. When different kinds of coolants supplied at the same mass flow rate, the coolants with low densities, i.e., H2 and He, have the lowest peak temperature compared with the coolants with large densities, i.e., N2 and CO2. The coolants with low densities have a large ejecting velocity which provides large kinetic energy to penetrate deeply in the porous media. In addition, when the ejecting velocity is large enough, a recirculation is formed in front of the leading edge and pushes the high temperature region located in stagnation region away from the leading edge. However, when the coolants are ejected at the same velocity, the coolants with large densities exhibit better cooling performance.

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Simulation of Sharp Leading Edge Aerothermodynamics

Cited by 12 publications

References 17 publications

Effects of Continuum Breakdown on Hypersonic Aerothermodynamics

Effects of Continuum Breakdown on Hypersonic Aerothermodynamics

Effect of ZrB2 Particle Size on Pressureless Sintering of ZrB2 - ß-Sic Composites

Effects of Coolants of Double Layer Transpiration Cooling System in the Leading Edge of a Hypersonic Vehicle

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