Effect of Thermal Ablation at the Fluid-Solid Interface of a Hypersonic Reentry Vehicle in Rarefied Flow Regime

Author(s):  
Ahilan Appar ◽  
Rakesh Kumar
Author(s):  
Andrew D. Strongrich ◽  
Alina A. Alexeenko

Convective heat transfer in the transitional rarefied flow regime is evaluated both numerically using the ES-BGK collision model and experimentally for freely suspended silicon beams. Results are compared to both empirically derived continuum correlations as well as analytical free-molecule solutions, demonstrating a monotonic nonlinear transition between the two regimes. Both horizontal and vertical orientations were explored in an effort to evaluate the potential influence of buoyancy on heat transfer performance. Results demonstrate that such effects are largely insignificant for transitional rarefied flows and convective thermal dissipation is instead driven by thermal creep phenomena.


Author(s):  
Kevin Gott ◽  
Anil K. Kulkarni ◽  
Jogender Singh

Several modifications to physical vapor deposition (PVD) models are proposed to address the deficiencies in current theoretical studies. Simple calculations show that the flow regime of PVD fabrications will most likely vary from a continuum flow to a rarefied flow in the vacuum chamber as the vapor cloud expands toward the substrate. The flow regime for an evaporated ideal gas is calculated and then an improved equation of state is constructed and analyzed that more accurately describes vaporized metals. The result, combined with experimental observations, suggests PVD fabrication is best represented by a multi-regime flow. Then, a CFD analysis is summarized that further validates the multi-regime analysis hypothesis. Finally, a methodology for constructing and implementing the results of a theoretical multi-regime PVD model is presented.


Author(s):  
Rakesh Kumar ◽  
TOng Zhu ◽  
Evgeny Titov ◽  
Deborah Levin
Keyword(s):  

AIAA Journal ◽  
1967 ◽  
Vol 5 (10) ◽  
pp. 1901-1902
Author(s):  
M. I. KUSSOY
Keyword(s):  

Author(s):  
J.A. Panitz

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.


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