607 research outputs found

    The aerothermal environment and material response: A review

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    Aerothermal environments are discussed with emphasis on the cold dense and warm atmospheres of Saturn and Uranus. The spectral distribution of the incident radiation flux is given for the Saturn nominal entry. Saturn and Uranus stagnation point heat pulses with no ablation are compared. Calculations for small flow rates, important in the Saturn-Uranus nominal type entries, are given to investigate the effects due to the mixing layer separation. Analytical and experimental techniques applicable to flowfield calculations are reviewed with emphasis on two--dimensional flow capabilities. Transport properties are reviewed in terms of flowfield calculations along with radiation transport codes. Various approaches to entry calculations are presented. It is indicated that only certain aspects of the aerothermal environment can be simulated in the laboratory and that although flight experiments are becoming feasible they are so expensive that they are prohibitive. Recommendations for further study are included

    Rapid methods for calculating radiation transport in the entry environment

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    A procedure is developed for the prediction of radiation transport events in the context of the entry heating environment. The equivalent-width and exponential approximations are employed to reduce the computational requirements of the governing equations. Novel features are introduced in the use of an Elsasser band model to estimate line overlapping events and in the formulation of the wall reflection events. A matrix of calculations is presented to allow an assessment of the trade-offs between accuracy and computational efforts. It is concluded that the equivalent width model allows significant savings in computational effort with only modest penalties in accuracy. Consequently, the model should be viewed as an attractive candidate for use in radiation-coupled flow field prediction procedures

    Spectral absorption coefficients of carbon, nitrogen, and oxygen atoms

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    Spectral absorption coefficients of carbon, nitrogen, and oxygen atoms tabulated for use in radiant energy transfer calculation

    User's manual for RAD/EQUIL/1973: A general purpose radiation transport program

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    A procedure is described for implementing the RAD/EQUIL/1973 program, and instructions are given which allow the program input to be prepared, the output to be interpreted, the operating procedures identified which must be followed, and the meaning of the error messages to be understood. The structure of the program is described through a verbal description, a FORTRAN variables list, and a listing of the program

    Further studies of the coupled chemically reacting boundary layer and charring ablator. Part 1 - Summary Final report

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    Computer program development for charring ablative materials, chemically reacting laminar boundary layers, and turbulent boundary layer initiatio

    Advanced methods for calculating radiation transport in ablation-product contaminated boundary layers

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    Prediction method for calculating radiation transport in ablation product contaminated, hypersonic boundary layer

    Flow field prediction and analysis, project fire final report

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    Flow field, and convective and radiative heating predictions for NASA Fire project reentry package trajectorie

    Indium oxide diffusion barriers for Al/Si metallizations

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    Indium oxide (In2O3) films were prepared by reactive rf sputtering of an In target in O2/Ar plasma. We have investigated the application of these films as diffusion barriers in Si/In2O3/Al and Si/TiSi2.3/In2O3/Al metallizations. Scanning transmission electron microscopy together with energy dispersive analysis of x ray of cross-sectional Si/In2O3/Al specimens, and electrical measurements on shallow n + -p junction diodes were used to evaluate the diffusion barrier capability of In2O3 films. We find that 100-nm-thick In2O3 layers prevent the intermixing between Al and Si in Si/In2O3/Al contacts up to 650°C for 30 min, which makes this material one of the best thin-film diffusion barriers on record between Al and Si. (The Si-Al eutectic temperature is 577°C, Al melts at 660°C.) When a contacting layer of titanium silicide is incorporated to form a Si/TiSi2.3/In2O3/Al metallization structure, the thermal stability of the contact drops to 600°C for 30 min heat treatment
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