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- Charring ablators (2)
- Pyrolysis gas (2)
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- Ablation (1)
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- Adaptive pattern recognition and classification (1)
- Arc-jet environment (1)
- Back propagation neural network (BPNN); Learning vector quantization (LVQ) (1)
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- Charring Ablator (1)
- Charring ablator (1)
- Chemical nonequilibrium (1)
- Computational fluid dynamics (1)
- Geometric Effects (1)
- Heat Shield (1)
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- Heat transfer (1)
- Hypersonic flow field (1)
- Microgravity (1)
- Multi-dimensional modeling (1)
- Oxidation (1)
- PICA (1)
- Phenolic impregnated carbon ablator (1)
- Porous carbon fiber material (1)
- Re-entry vehicle (1)
- Self-organizing feature map (SOFM) (1)
- Source detection (1)
- Spallation (1)
- Spalled particles (1)
Articles 1 - 9 of 9
Full-Text Articles in Space Vehicles
Numerical Investigation On Charring Ablator Geometric Effects: Study Of Stardust Sample Return Capsule Heat Shield, Haoyue Weng, Alexandre Martin
Numerical Investigation On Charring Ablator Geometric Effects: Study Of Stardust Sample Return Capsule Heat Shield, Haoyue Weng, Alexandre Martin
Mechanical Engineering Faculty Publications
Sample geometry is very influential in small charring ablative articles where 1D assumption might not be accurate. In heat shield design, 1D is often assumed since the nose radius is much larger than the thickness of charring. Whether the 1D assumption is valid for the heat shield is unknown. Therefore, the geometric effects of Stardust sample return capsule heat shield are numerically studied using a material response program. The developed computer program models material charring, conductive heat transfer, surface energy balance, pyrolysis gas transport and orthotropic material properties in 3D Cartesian coordinates. Simulation results show that the centerline temperatures predicted …
Numerical Study Of Spallation Phenomenon In An Arc-Jet Environment, Raghava Davuluri, Alexandre Martin
Numerical Study Of Spallation Phenomenon In An Arc-Jet Environment, Raghava Davuluri, Alexandre Martin
Mechanical Engineering Faculty Publications
The spallation phenomenon might affect the aerodynamic heating rates of re-entry vehicles. To investigate spallation effects, a code is developed to compute the dynamics of spalled particles. The code uses a finite-rate chemistry model to study the chemical interactions of the particles with the flow field. The spallation code is one-way coupled to a CFD solver that models the hypersonic flow field around an ablative sample. Spalled particles behavior is numerically studied for argon and air flow field. The chemistry model is compared with that of Park's model which complies with oxidation and sublimation and shows disagreement for nitridation.
Volume Averaged Modeling Of The Oxidation Of Porous Carbon Fiber Material, Alexandre Martin
Volume Averaged Modeling Of The Oxidation Of Porous Carbon Fiber Material, Alexandre Martin
Mechanical Engineering Faculty Publications
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. This type of ablative material is composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Then, as the temperature rises, the surface of the porous matrix recess through ablative processes. For re-entry conditions typical of space exploration missions, this is mainly …
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator, Alexandre Martin
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator, Alexandre Martin
Mechanical Engineering Faculty Publications
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. These type of ablative material are composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Since the composition of the gas at the surface greatly affects the heat flux, and therefore the surface temperature, it is thus important to be able …
Multi-Dimensional Modeling Of Charring Ablators, Haoyue Weng, Huaibao Zhang, Ovais U. Khan, Alexandre Martin
Multi-Dimensional Modeling Of Charring Ablators, Haoyue Weng, Huaibao Zhang, Ovais U. Khan, Alexandre Martin
Mechanical Engineering Faculty Publications
Re-entry of a spacecraft occurs at the hypersonic regime where the flow field is extremely complex: high temperature gradients occurring in the shock-layer region ionize and dissociate the air. Even if a large portion of heat generated during this process is convected away in the surrounding air, a fraction of it is still transferred to the vehicle. Therefore, it is important to protect the vehicle with a suitable kind of shielding. Of the many techniques available today, use of ablative material is gaining popularity. The basic idea behind an ablating heat shield is that the energy incident on the spacecraft …
Numerical Modeling Of The Cn Spectral Emission Of The Stardust Re-Entry Vehicle, Alexandre Martin, Erin D. Farbar, Iain D. Boyd
Numerical Modeling Of The Cn Spectral Emission Of The Stardust Re-Entry Vehicle, Alexandre Martin, Erin D. Farbar, Iain D. Boyd
Mechanical Engineering Faculty Publications
Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple ow chemistry models. In order to obtain better predictions, an appropriate gas ow chemistry model needs …
A Microfabricated Segmented-Involute-Foil Regenerator For Enhancing Reliability And Performance Of Stirling Engines: Phase Iii Final Report For The Radioisotope Power Conversion Technology Nra Contract Nas3-03124, Mounir B. Ibrahim, David Gedeon, Gary Wood, Jeffrey Mclean
A Microfabricated Segmented-Involute-Foil Regenerator For Enhancing Reliability And Performance Of Stirling Engines: Phase Iii Final Report For The Radioisotope Power Conversion Technology Nra Contract Nas3-03124, Mounir B. Ibrahim, David Gedeon, Gary Wood, Jeffrey Mclean
Mechanical Engineering Faculty Publications
Under Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity …
Real-Time On-Line Space Research Laboratory Environment Monitoring With Off-Line Trend And Prediction Analysis, Kenol Jules, Paul P. Lin
Real-Time On-Line Space Research Laboratory Environment Monitoring With Off-Line Trend And Prediction Analysis, Kenol Jules, Paul P. Lin
Mechanical Engineering Faculty Publications
With the International Space Station currently operational, a significant amount of acceleration data is being down-linked, processed and analyzed daily on the ground on a continuous basis for the space station reduced gravity environment characterization, the vehicle design requirements verification and science data collection. To help understand the impact of the unique spacecraft environment on the science data, an artificial intelligence monitoring system was developed, which detects in near real time any change in the reduced gravity environment susceptible to affect the on-going experiments. Using a dynamic graphical display, the monitoring system allows science teams, at any time and any …
An Intelligent System For Monitoring The Microgravity Environment Quality On-Board The International Space Station, Paul P. Lin, Kenol Jules
An Intelligent System For Monitoring The Microgravity Environment Quality On-Board The International Space Station, Paul P. Lin, Kenol Jules
Mechanical Engineering Faculty Publications
An intelligent system for monitoring the microgravity environment quality on-board the International Space Station is presented. The monitoring system uses a new approach combining Kohonen's self-organizing feature map, learning vector quantization, and a back propagation neural network to recognize and classify the known and unknown patterns. Finally, fuzzy logic is used to assess the level of confidence associated with each vibrating source activation detected by the system.