Intrinsic thermocouple monitors welding.
Monitors welding based on weld characteristics and temperature gradients relation using constantan probe in contact with aluminum plate thermocouple junction
Cook, G. E.↗
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Results for “TEMPERATURE PROBE”
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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Global observations on the thermal balance of the nighttime protonosphere
Alouette 2 satellite electrostatic probe measurements of nighttime electron temperature and concentration
Brace, L. H.↗
Thermal control for planetary probes
Thermal control of planetary probes during the descent phase of a mission is examined. Emphasis was placed on the problems of atmospheric uncertainties to be encountered by the probes, insulation performance, and equipment temperature limits.
Mcmordie, R.↗
Measurement of atmospheric turbulence strength at high altitude with balloon-borne temperature sensors
A technique to measure a vertical profile of the optical strength of turbulence employs the measurement of a root mean square temperature difference between two microthermal probes carried aloft as part of a balloon payload. Microthermal fluctuations provide a measure for the density fluctuations of turbulence. Examination of recorded profiles of refractive-index structure coefficients reveals a turbulence structure which is organized into multiple, thin groupings of strong turbulence separated by relatively quiescent intervals of variable length.
Bufton, J. L.↗
Properties of the wake of small Langmuir probes on sounding rockets
Split Langmuir probes have been used to study the near wake of small Langmuir probes on sounding rockets. Experiments have been performed on two rocket flights using planar disk and cylindrical geometries, and the results are presented. Significant wake perturbations in plasma density and temperature were found due to the probe body itself, even though the probes were of the order of or smaller than the Debye length. The largest effects of the wake are seen in the electron collection characteristics of the probe. The wake of small probes show apparent magnetic field aligned structure, even though the probes were much smaller than the ion gyroradius. On one flight, a space charge potential large enough to substantially alter photoemission, -3.5 volts, was observed.
Bering, E. A.↗
Cameras for semiconductor process control
The application of X-ray topography to semiconductor process control is described, considering the novel features of the high speed camera and the difficulties associated with this technique. The most significant results on the effects of material defects on device performance are presented, including results obtained using wafers processed entirely within this institute. Defects were identified using the X-ray camera and correlations made with probe data. Also included are temperature dependent effects of material defects. Recent applications and improvements of X-ray topographs of silicon-on-sapphire and gallium arsenide are presented with a description of a real time TV system prototype and of the most recent vacuum chuck design. Discussion is included of our promotion of the use of the camera by various semiconductor manufacturers.
Porter, W. A.↗
Turbulence characteristics of compressor discharge flows
Turbulence measurements were conducted in a large gas turbine engine (JT9D) at the entrance to the diffuser duct, joining the compressor discharge to the combustor inlet. Hot film probe and hot wire probe measurements were obtained at temperatures from 450K (350F) (idle) to 608K (635F) (rich approach). At I.D. (25 percent span) and mid-span locations, the turbulence intensity increased slightly from 6 + or - percent at idle condition to 7 or - 1 percent at rich approach. At O.D. (75 percent span) the turbulent intensity increased more rapidly, from 7.5 + or - 0.5 percent at idle to 15 + or - 0.5 percent at rich approach. The spectra showed turbulent energy distributed uniformly over a 0.1 to 5 KHz bandwidth (down 3db) at all operating conditions, corresponding to random turbulence with velocity wave lengths of 2 cm to 1 meter travelling at the mean velocity of 100 m/sec. Tests results are given in tables and graphs.
Grant, H. P.↗
Mechanical property degradation and chemical interactions in Borsic/titanium composite
A study was undertaken to identify the mechanisms of mechanical property degradation in a Borsic (silicon-carbide coated boron) fiber reinforced Ti-3Al-2.5V composite exposed to elevated temperature. Samples containing 0.45 volume fraction of fibers were exposed, in vacuum, to temperatures from 700 K to 1255 K for times up to 240 hours. Room temperature tensile properties of unidirectional material were determined in both the longitudinal and transverse directions, before and after high-temperature exposure. Electron micro-probe analysis, scanning electron microscopy, and X-ray diffraction were used to determine the compounds formed and the extent of interaction between the boron, SiC coating, and matrix materials.
Brewer, W. D.↗
Galileo - Mission to Jupiter
The Galileo mission to Jupiter in the latter half of this decade is NASA's next step in the exploration of Jupiter. The primary science objectives are to study the satellites, the magnetosphere, and Jupiter's atmosphere. In general, there are four characteristics of the Galileo mission which provide the capability to address questions not answered by Voyager: (1) long-term observations - at least 11 orbits of Jupiter in nearly two years - will allow temporal studies of Io vulcanism as well as of interactions between the satellites and magnetosphere; (2) very close satellite flybys - at a distance less than 1000 km at each Galilean satellite - will allow in-depth studies of these satellites at distances 20 to 100 times closer than Voyager achieved; (3) an atmospheric entry probe will measure composition, structure, temperature, energy balance, cloud layer locations and structure, and particle size distribution in Jupiter's atmosphere; and (4) the Orbiter's advanced instrumentation will allow higher resolution and more detailed studies of the satellites, atmosphere, and magnetosphere
Casani, J. R.↗
Spectra of cosmic X-ray sources
X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term "spectroscopy" as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.
Holt, S. S.↗
Thermal reactor
A thermal reactor apparatus and method of pyrolyticaly decomposing silane gas into liquid silicon product and hydrogen by-product gas is disclosed. The thermal reactor has a reaction chamber which is heated well above the decomposition temperature of silane. An injector probe introduces the silane gas tangentially into the reaction chamber to form a first, outer, forwardly moving vortex containing the liquid silicon product and a second, inner, rewardly moving vortex containing the by-product hydrogen gas. The liquid silicon in the first outer vortex deposits onto the interior walls of the reaction chamber to form an equilibrium skull layer which flows to the forward or bottom end of the reaction chamber where it is removed. The by-product hydrogen gas in the second inner vortex is removed from the top or rear of the reaction chamber by a vortex finder. The injector probe which introduces the silane gas into the reaction chamber is continually cooled by a cooling jacket.
Levin, H.↗
The role of ring current O(+) in the formation of stable auroral red arcs
Observations of thermal and energetic ion populations by the Dynamics Explorer 1 satellite in the magnetospheric energy source region as well as nearly simultaneous Langmuir probe measurements of enhanced electron temperatures by Dynamics Explorer 2 within the stable auroral red (SAR) arc at F region heights are used to examine the role of heavy ions in the formation of SAR arcs. It is found that sufficient energy is transferred to the electron gas at high altitudes via Coulomb collisions between the observed ring current ions and thermal electrons to support the enhanced F region electron temperatures measured on these field lines. The latitudinal variation in the electron heating rates calculated using observed ion populations is consistent with the observed variation in electron temperature across the SAR arc. In all cases, ring current O(+) is the major source of energy for the SAR arcs.
Kozyra, J. U.↗
Recent advances in capacitance type of blade tip clearance measurements
Two recent electronic advances at NASA-Lewis that meet the blade tip clearance needs of a wide class of fans, compressors, and turbines are described. The first is a frequency modulated (FM) oscillator that requires only a single low cost ultrahigh frequency operational amplifier. Its carrier frequency is 42.8 MHz when used with a 61 cm long hermetically sealed coaxial cable. The oscillator can be calibrated in the static mode and has a negative peak frequency deviation of 400 kHz for a typical rotor blade. High temperature performance tests of the probe and 13 cm of the adjacent cable show good accuracy up to 600 C, the maximum which produces a clearance error of + or - 10 microns at a clearance of 500 microns. In the second advance, a guarded probe configuration allows a longer cable capacitance. The capacitance of the probe is part of a small time constant feedback in a high speed operational amplifier. The solution of the governing differential equation is applied to a ramp type of input. The results show an amplifier output that contains a term which is proportional to the derivative of the feedback capacitance. The capacitance is obtained by subtracting a balancing reference channel followed by an integration stage.
Barranger, John P.↗
Recent advances in capacitance type of blade tip clearance measurements
Two recent electronic advances at NASA-Lewis that meet the blade tip clearance needs of a wide class of fans, compressors, and turbines are described. The first is a frequency modulated (FM) oscillator that requires only a single low cost ultrahigh frequency operational amplifier. Its carrier frequency is 42.8 MHz when used with a 61 cm long hermetically sealed coaxial cable. The oscillator can be calibrated in the static mode and has a negative peak frequency deviation of 400 kHz for a typical rotor blade. High temperature performance tests of the probe and 13 cm of the adjacent cable show good accuracy up to 600 C, the maximum which produces a clearance error of + or - 10 microns at a clearance of 500 microns. In the second advance, a guarded probe configuration allows a longer cable capacitance. The capacitance of the probe is part of a small time constant feedback in a high speed operational amplifier. The solution of the governing differential equation is applied to a ramp type of input. The results show an amplifier output that contains a term which is proportional to the derivative of the feedback capacitance. The capacitance is obtained by subtracting a balancing reference channel followed by an integration stage.
Barranger, John P.↗
LOX/Hydrocarbon Combustion Instability Investigation
The LOX/Hydrocarbon Combustion Instability Investigation Program was structured to determine if the use of light hydrocarbon combustion fuels with liquid oxygen (LOX) produces combustion performance and stability behavior similar to the LOX/hydrogen propellant combination. In particular methane was investigated to determine if that fuel can be rated for combustion instability using the same techniques as previously used for LOX/hydrogen. These techniques included fuel temperature ramping and stability bomb tests. The hot fire program probed the combustion behavior of methane from ambient to subambient temperatures. Very interesting results were obtained from this program that have potential importance to future LOX/methane development programs. A very thorough and carefully reasoned documentation of the experimental data obtained is contained. The hot fire test logic and the associated tests are discussed. Subscale performance and stability rating testing was accomplished using 40,000 lb. thrust class hardware. Stability rating tests used both bombs and fuel temperature ramping techniques. The test program was successful in generating data for the evaluation of the methane stability characteristics relative to hydrogen and to anchor stability models. Data correlations, performance analysis, stability analyses, and key stability margin enhancement parameters are discussed.
Jensen, R. J.↗
Turbulence measurements and noise generation in a transonic cryogenic wind tunnel
A high-frequency combination probe was used to measure dynamic flow quality in the test section of the NASA Langley 0.3-m Transonic Cryogenic Tunnel. The probe measures fluctuating stagnation (total) temperature and pressure, static pressure, and flow angles in two orthogonal planes. Simultaneous measurements of unsteady total temperature and pressure were also made in the settling chamber of the tunnel. The data show that the stagnation temperature fluctuations remain constant, and the stagnation pressure fluctuations increase by a factor of two, as the flow accelerates from the settling chamber to the test section. In the test section, the maximum rms value of the normalized fluctuating velocity is 0.7 percent. Correlation coefficients failed to show vorticity, entropy, or sound as the dominant mode of turbulence in the tunnel.
Ng, W. F.↗
Dual Active Surface Heat Flux Gage Probe
A unique plug-type heat flux gage probe was tested in the NASA Ames Research Center 2x9 turbulent flow duct facility. The probe was fabricated by welding a miniature dual active surface heat flux gage body to the end of a hollow metal cylindrical bolt containing a metal inner tube. Cooling air flows through the inner tube, impinges onto the back of the gage body and then flows out through the annulus formed between the inner tube and the hollow bolt wall. Heat flux was generated in the duct facility with a Huels arc heater. The duct had a rectangular cross section and one wall was fabricated from 2.54 centimeter thick thermal insulation rigid surface material mounted onto an aluminum plate. To measure heat flux, the probe was inserted through the plate and insulating materials with the from of the gage located flush with the hot gas-side insulation surface. Absorbed heat fluxes measured with the probe were compared with absorbed heat fluxes measured with six water-cooled reference calorimeters. These calorimeters were located in a water-cooled metal duct wall which was located across from the probe position. Correspondence of transient and steady heat fluxes measured with the reference calorimeters and heat flux gage probe was generally within a satisfactory plus or minus 10 percent. This good correspondence was achieved even though the much cooler probe caused a large surface temperature disruption of 1000K between the metal gage and the insulation. However, this temperature disruption did not seriously effect the accuracy of the heat flux measurement. A current application for dual active surface heat flux gages is for transient and steady absorbed heat flux, surface temperature and heat transfer coefficient measurements on the surface of an oxidizer turbine inlet deflector operating in a space shuttle test bed engine.
Liebert, Curt H.↗
Apparatus Tests Thermocouples For Seebeck Inhomogeneity
Automated apparatus reveals sources of error not revealed in calibration. Computer-controlled apparatus detects and measures Seebeck inhomogeneities in sheathed thermocouples. Measures thermocouple output voltage as function of position of probe along sharp gradient of temperature. Abnormal variations in voltage-versus-position data indicative of Seebeck inhomogeneities. Prototype for development of standard method and equipment for routine acceptance/rejection testing of sheathed thermocouples in industrial and research laboratories.
Burkett, Cecil G., Jr.↗