Influence of opposing slits on molecular flow from an isothermal enclosure at low densities
Particle density measurement of cesium vapor in isothermal enclosure at low densities
DENSITY MEASUREMENT↗
SEARCH · Engineering Papers
Results for “Enclosures”
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.
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Magnetic field reduction in an expandable superconducting enclosure.
Trapped magnetic field intensity reduced in flexible walled superconducting enclosure of variable cross section
MAGNETIC FIELD INTENSITY↗
An experimental and analytical investigation of balloon-type enclosures for thermal control of satellites
Evaluation of double wall balloon enclosure for thermal control of inertial satellites
Sweet, G. E.↗
Mass spectrometer leak testing by a calibrated enclosure method.
Mass spectrometer leak testing by calibrated enclosure method for quantification of gaseous leaks in large complex systems
Hollinger, D. L.↗
Vibration effects on convective heat transfer in enclosures
Mechanical vibration effects on natural convective heat transfer in enclosure of rectangular cross section
Bell, C. J.↗
A script-F matrix formulation for enclosures with arbitrary surface emission and reflection characteristics
Script-F radiative interchange matrix for enclosures with arbitrary surface emission and reflection characteristics
Bobco, R. P.↗
Radio frequency shielded enclosure Patent
Method and apparatus for bowing of instrument panels to improve radio frequency shielded enclosure
Young, H.↗
An experimental investigation of three balloon-type enclosures for thermal control of satellites
Thermal vacuum tests of three balloon-type enclosures for thermal control of satellites
Sweet, G. E.↗
A four-panel enclosure protects from explosion
Development of multi-layered baffle as enclosure to protect personnel from effects of explosion during production of ammunition is discussed. Advantages of new system over previous systems are described. Illustration of typical panel structure is provided.
King, P. V.↗
The use of large cylindrical enclosures as a cost effective approach to reverberant acoustic testing
The feasibility of using existing cylindrical enclosures as cost effective substitutes for reverberant acoustic test chambers is investigated. In particular the performance of two large cylindrical environmental chambers, 1400 and 14,000 cu m in volume, is evaluated in detail. Reverberant acoustic chamber characteristics are predicted using classical acoustic theory and are compared to results obtained from actual chamber measurements. A method of scaling low level test results to predict the performance of a particular driver/horn/chamber configuration is also discussed. This prediction technique is confirmed by actual test data using a 200 kilowatt acoustic generator.
On, F. J.↗
Pressure- and buoyancy-driven thermal convection in a rectangular enclosure
Results are presented for unsteady laminar thermal convection in compressible fluids at various reduced levels of gravity in a rectangular enclosure which is heated on one side and cooled on the opposite side. The results were obtained by solving numerically the equations of conservation for a viscous, compressible, heat-conducting, ideal gas in the presence of a gravitational body force. The formulation differs from the Boussinesq simplification in that the effects of variable density are completely retained. A conservative, explicit, time-dependent, finite-difference technique was used and good agreement was found for the limited cases where direct comparison with previous investigations was possible. The solutions show that the thermally induced motion is acoustic in nature at low levels of gravity and that the unsteady-state rate of heat transfer is thereby greatly enhanced relative to pure conduction. The nonlinear variable density profile skews the streamlines towards the cooler walls but is shown to have little effect on the steady-state isotherms.
Spradley, L. W.↗
Solar cell is housed in light-bulb enclosure
Inexpensive, conventional solar-cell module uses focusing principle of electric lamp in reverse to produce electric power from sunlight. Standard outdoor light enclosure provides low-cost housing which concentrates sunlight in solar cell. Unit is capable of producing approximately 1 watt of electric power.
Evans, J. C., Jr.↗
Thermal convection in an enclosure due to vibrations aboard spacecraft
The paper discusses thermal convection in an enclosure induced by spacecraft vibrations (g-jitter). Under normal circumstances (no maneuvers, no intentional spinning of the spacecraft) the g-jitter generates predominantly oscillatory velocity and temperature fields with zero time-mean values. The g-jitter can also generate secondary flows with non-zero mean, but they are of much smaller order. Some implications of the g-jitter on materials processing in space are discussed
Kamotani, Y.↗
Free convection in enclosures exposed to compressive heating
An experimental study of heat transfer in a vertical annulus and a three-dimensional gap used to establish the influence of compressive heating on the convective process in enclosures is presented. Test runs were made using helium gas with compressive rates of 6, 15, and 30 psi/min. Temperature and pressure histories were reduced to film coefficients based on nodal modeling of the test geometries. The data are correlated in terms of free convection parameters. The heat transfer correlations show virtually no influence of compression rate and only a slight dependence on geometry. The correlations will be applied to the design of a vented Galileo mission descent module parachuting into the Jupiter atmosphere.
Bobco, R. P.↗
Energy accommodation of 5-50 eV ions within an enclosure
Beams of 5-50 eV He(+), Ar(+), Ne(+), O(+), and N2(+) ions were directed into an aluminum sphere, and the equilibrium number density of the atom or molecules was measured inside the sphere using a quadrupole mass spectrometer and signal averaging techniques. The equilibrium number density is inversely proportional to the average speed of the atoms; thus, the results are expressed in terms of the speed ratio, R = V(i)/V(s), where V(i) is the average speed within the enclosure, and V(s) is the average speed of atoms fully accommodated to the temperature of the wall. The speed ratios vary between 1.0 and 1.8. For N2, several values of R were less than 1; this was largely due to desorbed N2. There was no detectable number density for O, which is explained by the reaction of O with the surface.
Humphris, R. R.↗
Effect of enclosure shape on natural convection velocities
A numerical analysis was performed to compare natural convection velocities in two dimensional enclosures of various shape. The following shapes were investigated: circle, square, horizontal and upright 2 x 1 aspect ratio rectangles, horizontal and upright half circles, diamond. In all cases, the length scale in the various dimensionless parameters, such as Rayleigh number, is defined as the diameter of the equal area circle. Natural convection velocities were calculated for Rayleigh numbers of 1000 and 5000 with the temperature difference taken to be across (1) the maximum horizontal dimension, (2) the median horizontal line (line through centroid) and (3) the horizontal distance such that the temperature gradient is the same for shapes of equal area. For the class of shapes including the square, upright half circle and upright rectangle, the computed velocities were found to agree very closely with that of the equal area circle when the temperature difference is taken to be across the maximum horizontal dimension (condition (a)). The velocities for the horizontal rectangle and half circle were found to be approximately one half that of the equal area circle for the same condition. Better overall agreement among all shapes was obtained by setting the temperature difference across a distance such that the temperature gradients were equal for shapes of equal area.
Robertson, S. J.↗
Noise transmission into semicylindrical enclosures through discretely stiffened curved panels
An analytical study of sound transmission into semicylindrical enclosures through discretely stiffened curved elastic panels is presented. The transmitted sound is estimated by solving the acoustic wave equation for the interior acoustic field, a Galerkin-like method being used. This solution is then coupled to the vibration of the stiffened panels. The response characteristics of these panels are determined by using a modal analysis where the modes are obtained by the finite element-strip method. Numerical results include spectra of the interior sound pressure due to white noise, turbulent boundary layer and propeller noise inputs.
Chang, M. T.↗
Measuring Moisture in Sealed Electronic Enclosures
Instrument checks trace amounts accurately. Moisture in hermeticallysealed electronic equipment measured by instrument designed for field use. Instrument also measures pressure, volume, and contaminants of gas in sealed enclosure. Plumbing for instrument uses vacuum-tight valves so any portion of instrument cleansed by opening certain valves to vacuum source. To ensure accuracy, manifolds are of minimal volume, each comprising only volume within cross-shaped tubing fittings.
Krieg, Herman C., Jr.↗