Search NASA⌕ Search

SEARCH · Search NASA

Results for “process simulation”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Numerical simulation of electrophoresis separation processes

A new Petrov-Galerkin finite element formulation has been proposed for transient convection-diffusion problems. Most Petrov-Galerkin formulations take into account the spatial discretization, and the weighting functions so developed give satisfactory solutions for steady state problems. Though these schemes can be used for transient problems, there is scope for improvement. The schemes proposed here, which consider temporal as well as spatial discretization, provide improved solutions. Electrophoresis, which involves the motion of charged entities under the influence of an applied electric field, is governed by equations similiar to those encountered in fluid flow problems, i.e., transient convection-diffusion equations. Test problems are solved in electrophoresis and fluid flow. The results obtained are satisfactory. It is also expected that these schemes, suitably adapted, will improve the numerical solutions of the compressible Euler and the Navier-Stokes equations.

Ganjoo, D. K.↗
NASA NTRS1989

Simulation of collisional transport processes and the stability of planetary rings

The utility of the phase-space fluid method for the study of planetary ring dynamics is presently demonstrated through the numerical solution of a model kinetic equation for a flattened Keplerian disk. Attention is given to ringlets composed of single-sized particles, as well as to ringlets composed of two different-sized particles; in the latter case, the ringlets evolve in such a way that the lighter particles are confined by the heavier ones. The results obtained indicate that some natural process may sharpen the optical depth profile of edges even without an external forcing mechanism, and that intermediate optical depths are dynamically preferred in some cases.

Brophy, Thomas G.↗
NASA NTRS1993

Laboratory simulations of lunar darkening processes

It was clear long before the Apollo missions that a darkening process occurs on the moon. However, its nature remains controversial and elusive. Current evidence implies that the darkening is associated with, and is probably caused by, submicroscopic metallic iron in the regolith. Questions discussed at the workshop include: (1) under what conditions will impact vitrification produce a dark glass; (2) what is the role of the submicroscopic metallic Fe (SMFe) in the lunar darkening process; (3) how is the SMFe produced; (4) is there a significant component of the regolith that has been deposited from a vapor, if so, what form is it in, and how can it be recognized, what are its effects on the chemistry of the regolith; (5) how do the processes of impact vitrification, vaporization, sputtering, and SMFe production vary as a function of distance from the sun and location in planetary magnetospheres; and (6) what other processes might affect optical properties. Ices have lower melting and boiling temperatures and sputtering yields several orders of magnitude larger than silicates. Hence, analogous processes will occur to an even greater extent on satellites of the outer planets, and these questions are relevant to those bodies as well.

Hapke, B.↗
NASA NTRS2006

Process Demonstration For Lunar In Situ Resource Utilization-Molten Oxide Electrolysis (MSFC Independent Research and Development Project No. 5-81)

The purpose of this Focus Area Independent Research and Development project was to conduct, at Marshall Space Flight Center, an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis process to produce oxygen and metal. In essence, the vision was to develop two key technologies, the first to produce materials (oxygen, metals, and silicon) from lunar resources and the second to produce energy by photocell production on the Moon using these materials. Together, these two technologies have the potential to greatly reduce the costs and risks of NASA s human exploration program. Further, it is believed that these technologies are the key first step toward harvesting abundant materials and energy independent of Earth s resources.

Curreri, P. A.↗
NASA NTRS2010

Genesis of Pre-Hurricane Felix (2007): The Role of the Easterly Wave Critical Layer - Part 1

The formation of pre Hurricane Felix (2007) in a tropical easterly wave is examined in a two-part study using the Weather Research and Forecasting (WRF) model with a high-resolution nested grid configuration that permits the representation of cloud system processes. The simulation commences during the wave stage of the precursor African easterly-wave disturbance. Here the simulated and observed developments are compared, while in Part II of the study various large-scale analyses, physical parameterizations, and initialization times are explored to document model sensitivities. In this first part the authors focus on the wave/vortex morphology, its interaction with the adjacent intertropical convergence zone complex, and the vorticity balance in the neighborhood of the developing storm. Analysis of the model simulation points to a bottom-up development process within the wave critical layer and supports the three new hypotheses of tropical cyclone formation proposed recently by Dunkerton, Montgomery, and Wang. It is shown also that low-level convergence associated with the ITCZ helps to enhance the wave signal and extend the "wave pouch" from the jet level to the top of the atmospheric boundary layer. The region of a quasi-closed Lagrangian circulation within the wave pouch provides a focal point for diabatic merger of convective vortices and their vortical remnants. The wave pouch serves also to protect the moist air inside from dry air intrusion, providing a favorable environment for sustained deep convection. Consistent with the authors' earlier findings, the tropical storm forms near the center of the wave pouch via system-scale convergence in the lower troposphere and vorticity aggregation. Components of the vorticity balance are shown to be scale dependent, with the immediate effects of cloud processes confined more closely to the storm center than the overturning Eliassen circulation induced by diabatic heating, the influence of which extends to larger radii.

Wang, Zhuo↗
NASA NTRS2020

Contribution of Infiltration Process Uncertainty on the Simulation of Terrestrial Water and Energy Budgets

The infiltration step is the major forking point of precipitation partition in land surface models, which plays a more significant role than canopy interception for simulating water and energy budgets.In this study, we found significant differences in water and energy-related outputs amount JULES, Noah, Noah-MP, and VIC. The differences are directly or indirectly related to the infiltration components in the models. Those differences add uncertainties to the applications of land surface models. Thorough evaluations are needed to determine the reliability of infiltration schemes used in these models.

Wang, Shugong↗
NASA NTRSDate not supplied

Gaseous By-Product of Thermal Vacuum Processing of Lunar Highland Simulant

Scientists at Kennedy Space Center are advancing technologies to achieve oxygen extraction on the Lunar surface. One such technology is Molten Regolith Electrolysis (MRE) in which regolith simulant is melted under high temperatures to perform oxygen extraction through electrolysis of the melt pool. A study was conducted to understand the molten formation and proper-ties of Lunar Highlands Simulants (LHS-1) under high vacuum environments ranging between 10-6 Torr. These studies include investigating the regolith melt behavior and by-product gas analysis systems to prepare for pilot plant development and operations. The off-gassing rates and pressure build-up, gaseous compounds, and material compatibility may be a risk to MRE systems. The KSC findings are reported here for inclusion into future mis-sion architecture and operational planning. The four stages of the experiment were vacuum, resistive heating, regolith melt and gas detection. The regolith mass of 70 g was melted in a 40 cm tall x 50 cm diameter vacuum chamber at temperature increase rate 47 ℃ /min and ramp rate of 1 ampere/3 min up to an 18-amp maximum. The test is conducted for about 60 minutes and the constituent gases produced during heating of regolith is monitored with a re-sidual gas analyzer. During the molten formation, primary off-gassing volatiles included water vapor (18 amu), a peak at 44 amu (FeO2 – expected), and atomic oxygen (16 amu), among a series of other compounds that could create compatibility issues such as magnesium, chlorine, and silicon oxide. These results add to the knowledge required for successful oxygen extraction on the moon.

Molten Regolith Electrolysis↗