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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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At least 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
NASA NTRS1951

Performance of single-stage compressor designed on basis of constant total enthalpy with symmetrical velocity diagram at all radii and velocity ratio of 0.7 at rotor hub / Jack R. Burtt and Robert J. Jackson

A typical inlet axial-flow compressor inlet stage, which was designed on the basis of constant total enthalpy with symmetrical velocity diagram at all radii, was investigated. At a tip speed of 1126 feet per second, a peak pressure ratio of 1.28 was obtained at an efficiency of 0.76. At a tip speed, the highest practical flow was 28 pounds per second per square foot frontal area with an efficiency of 0.78. Data for a rotor relative inlet Mach number range of from 0.5 to 0.875 indicates that the critical value for any stage radial element is approximately 0.80 for the stage investigated.

FANS↗
NASA NTRS1957

Experimental evaluation of methods for improving diffuser-exit total-pressure profiles for a side-inlet model at Mach number 1.91

Distortion effects of the following model additions or changes were studied: (1) constant-area mixing lengths at the end of the subsonic diffuser, (2) screens with systematic variations in mesh and flow-area blockage, (3) bleeds slots on the inlet cowl, and (4) a simulated compressor hub. Data at a diffuser-exit Mach number of 0.36 are compared with data of a similar study at Mach 0.20. At the higher Mach number, the same length of constant-area mixing was less effective in reducing total-pressure distortions, while the use of screens was more effective.

Klann, John L↗
NASA NTRS1958

Heat-Transfer Measurements in Free Flight at Mach Numbers up to 14.6 on a Flat-Faced Conical Nose with a Total Angle of 29 Degrees

Skin-temperature measurements have been made at several locations on a flat-faced cone-cylinder nose which was flight tested on a fivestage rocket-propeller model to a Mach number of 14.64 and a free-stream Reynolds number of 2.0 x 10(exp 6), based on flat-face diameter, at an altitude of 66,300 feet. The copper nose had a 29 deg total-angle conical section which was 1.6 flat-face diameters long. The aerodynamic-heating rates determined from the temperature measurements reached 1,440 Btu/( sec) (sq ft) on the flat face. The heating rates near the center of the flat face agreed well at Mach numbers up to 13.6 with those obtained by a theory for laminar stagnation-point heating in equilibrium dissociated air (Avco Res. Rep. 1). At Mach numbers above 13.6, the heating rates at locations near the center of the flat face became progressively lower than stagnation-point theory and. were 29 percent lower at Mach number 14.6 at the end. of the test. The reason for this behavior of the heating on the central part of the flat face was not determined. Excluding the relatively low heating rates that occurred on the central part of the nose at the highest Mach numbers, the distribution of experimental heating along the innermost 0.79 of the flat-face radius, expressed as a percentage of stagnation-point heating, was in fair agreement with the distribution predicted by laminar theory. At a location of 0.71 radii from the stagnation point, the experimental heating was very near 130 percent of the theoretical stagnation-point rate at Mach numbers from 11 to 14.5. The experimental beating rates on the conical section of the nose were in good agreement with laminar-cone theory using the assumption of theoretical sharp-cone static pressure on the conical section.

Rumsey, Charles B↗
NASA NTRS1923

Point drag and total drag of navy struts no. 1 modified

This report deals with the results of tests on struts conducted at Washington Navy Yard. Two models of the modified Navy strut, no. 1, were tested in the 8 by 8 foot wind tunnel. The tests were made to determine the total resistance end effect and the pressure distribution at various wind-tunnel speeds with the length of the strut transverse to the current. Only the measurements made at zero pitch and yaw are given in this report.

Zahm, A F↗
NASA NTRS1946

Variation with Mach Number of Static and Total Pressures Through Various Screens

Tests were conducted in the Langley 24-inch highspeed tunnel to ascertain the static-pressure and total-pressure losses through screens ranging in mesh from 3 to 12 wires per inch and in wire diameter from 0.023 to 0.041 inch. Data were obtained from a Mach number of approximately 0.20 up to the maximum (choking) Mach number obtainable for each screen. The results of this investigation indicate that the pressure losses increase with increasing Mach number until the choking Mach number, which can be computed, is reached. Since choking imposes a restriction on the mass rate of flow and maximum losses are incurred at this condition, great care must be taken in selecting the screen mesh and wire dimmeter for an installation so that the choking Mach number is

Adler, Alfred A↗
NASA NTRS1993

Satellite-derived photosynthetically available and total solar irradiance at the surface during FIFE's intensive field campaigns

Satellite-derived photosynthetically available and total solar irradiance at the surface during First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment's (FIFE) intensive field compaigns are addressed. Graphs showing photosynthetically available radiation (PAR) vs. Julian Day and insolation vs. Julian Day are included.

Frouin, Robert↗
NASA NTRS1992

The role of metrics and measurements in a software intensive total quality management environment

Paramax Space Systems began its mission as a member of the Rockwell Space Operations Company (RSOC) team which was the successful bidder on a massive operations consolidation contract for the Mission Operations Directorate (MOD) at JSC. The contract awarded to the team was the Space Transportation System Operations Contract (STSOC). Our initial challenge was to accept responsibility for a very large, highly complex and fragmented collection of software from eleven different contractors and transform it into a coherent, operational baseline. Concurrently, we had to integrate a diverse group of people from eleven different companies into a single, cohesive team. Paramax executives recognized the absolute necessity to develop a business culture based on the concept of employee involvement to execute and improve the complex process of our new environment. Our executives clearly understood that management needed to set the example and lead the way to quality improvement. The total quality management policy and the metrics used in this endeavor are presented.

Daniels, Charles B.↗
NASA NTRS1992

The Eighth Annual NASA/Contractors Conference and 1991 National Symposium on Quality and Productivity: Extending the boundaries of total quality management

The Eighth Annual NASA/Contractors Conference and 1991 National Symposium on Quality and Productivity provided a forum to exchange knowledge and experiences in these areas of continuous improvement. The more than 1,100 attendees from government, industry, academia, community groups, and the international arena had a chance to learn about methods, tools, and strategies for excellence and to discuss continuous improvement strategies, successes, and failures. This event, linked via satellite to concurrent conferences hosted by the NASA Goddard Space Flight Center in Greenbelt, Maryland, and Martin Marietta Astronautics Group in Denver, Colorado, also explored extending the boundaries of Total Quality Management to include partnerships for quality within communities and encouraged examination, evaluation, and change to incorporate the principles of continuous improvement.

Templeton, Geoffrey B.↗
NASA NTRS1993

Total systems design analysis of high performance structures

Designer-control parameters were identified at interdiscipline interfaces to optimize structural systems performance and downstream development and operations with reliability and least life-cycle cost. Interface tasks and iterations are tracked through a matrix of performance disciplines integration versus manufacturing, verification, and operations interactions for a total system design analysis. Performance integration tasks include shapes, sizes, environments, and materials. Integrity integrating tasks are reliability and recurring structural costs. Significant interface designer control parameters were noted as shapes, dimensions, probability range factors, and cost. Structural failure concept is presented, and first-order reliability and deterministic methods, benefits, and limitations are discussed. A deterministic reliability technique combining benefits of both is proposed for static structures which is also timely and economically verifiable. Though launch vehicle environments were primarily considered, the system design process is applicable to any surface system using its own unique filed environments.

Verderaime, V.↗
NASA NTRS1993

A high temperature fatigue life prediction computer code based on the total strain version of StrainRange Partitioning (SRP)

A recently developed high-temperature fatigue life prediction computer code is presented and an example of its usage given. The code discussed is based on the Total Strain version of Strainrange Partitioning (TS-SRP). Included in this code are procedures for characterizing the creep-fatigue durability behavior of an alloy according to TS-SRP guidelines and predicting cyclic life for complex cycle types for both isothermal and thermomechanical conditions. A reasonably extensive materials properties database is included with the code.

Mcgaw, Michael A.↗
NASA NTRS1993

A chemical sensor and biosensor based totally automated water quality monitor for extended space flight: Step 1

The result of a literature search to consider what technologies should be represented in a totally automated water quality monitor for extended space flight is presented. It is the result of the first summer in a three year JOVE project. The next step will be to build a test platform at the Authors' school, St. John Fisher College. This will involve undergraduates in NASA related research. The test flow injection analysis system will be used to test the detection limit of sensors and the performance of sensors in groups. Sensor companies and research groups will be encouraged to produce sensors which are not currently available and are needed for this project.

Smith, Robert S.↗
NASA NTRS1994

Ability of the total strain version of strainrange partitioning to characterize thermomechanical fatigue behavior

Strainrange partitioning (SRP) was originally developed on an inelastic strain basis for isothermal fatigue in the high-strain regime where the inelastic strainrange could be determined accurately. However, most power-generating equipment operates in the regime where the inelastic strains are small and difficult to determine with any degree of accuracy. This shortcoming led to the development of the total strain version of SRP (TS-SRP). Power-generating equipment seldom operates under isothermal conditions, and isothermal life prediction methods cannot be depended on to predict the lives of anisothermal cycles. To overcome this shortcoming, a method was proposed for extending TS-SRP to characterize anisothermal fatigue behavior and to predict the lives of thermomechanical fatigue (TMF) cycles using apppropriate anisothermal data. The viability of this method, referred to as TMF/TS-SRP, was demonstrated using TMF data for two high-temperature aerospace alloys. In this report, data from the literature are used to examine the ability of TMF/TS-SRP to characterize the failure and flow behavior of three low-strength, high-ductility alloys widely used for ground-based power-generating equipment. The three alloys are type 304 stainless steel, 1Cr-1Mo-0.25V steel, and 2.25Cr-1Mo steel. Because of the limited nature of the data, it was possible to evaluate the characterization, but not the predictive capability of TMF/TS-SRP.

Saltsman, James F.↗
NASA NTRS1994

Recalculated values of the total ozone amount over Oslo, 60 deg N, for the period 1979-1992

The total ozone amount over Oslo has been measured with the Dobson spectrophotometer No 56. The instrument was modified, calibrated, and intercompared in 1977 in Boulder. A new intercomparison was made in 1986 in Arosa. Much work has been done to make the zenith charts reliable. A new method has been introduced where one takes into account the change in the shape of the zenith chart curves which is caused by a change of the ozone profile when the ozone amount changes. According to the conclusion derived from the intercomparison in Arosa 1986, the instrument has not been stable. The R-N tables had to be altered, but not the Q-tables. We have tried to account for this change in our handling of the observation data. No statistical analyses of these data has yet been made, but the monthly averages of the raw data show a negative linear trend of about 4 percent for the whole period.

Larsen, Soren H. H.↗
NASA NTRS1994

Total ozone change estimations for different time intervals

To investigate total ozone behavior in different time intervals for the 40 deg - 52 deg N and 53 deg - 64 deg N latitudinal bands sliding 11 year linear trends with the first interval from 1959 to 1969 and the final one from 1980 to 1990 were computed. The most recent 11-year trends are negative and have larger absolute values than in the past. The trend values in the period from 1980 to 1990 in the 53 deg - 64 deg N band are minus 4.3 percent (winter), minus 3.2 percent (summer), and minus 3.8 percent (annual) per decade, and in the 40 deg - 52 deg N band they are minus 5.9 percent (winter), minus 2.7 percent (summer), and minus 3.6 percent (annual) per decade.

Fioletov, Vitali E.↗
NASA NTRS1994

Revision of the Dobson total ozone series at Hohenpeissenberg

Total ozone measurements with the Dobson No. 104 (D 104) have been performed at the Meteorological Observatory Hohenpeissenberg since 1967. A critical review of this time series and the comparison with other instruments like TOMS or Brewer spectrophotometer revealed some intervals with uncertainties. Especially in the early eighties a monthly mean bias of about minus 3 percent to TOMS-data with annual variations depending on the mean sun-height exists. An extreme amplitude of 5.6 percent occurs in 1980 with minus 0.76 percent (February) and minus 6.36 percent (July). Two different methods were applied to reprocess the Dobson data set. A comparison of the differently recalculated data showed, that the application of N-corrections by means of the standard-lamp tests starting from the reference values of the Arosa Intercomparison 1986 yields better results than the N-corrections based on a Langley-pilot of the Arosa Intercomparison 1978. The extreme amplitude of the year 1980 is now reduced to 3.02 percent. There is still a slight drift in the monthly and yearly mean differences between TOMS and revised Dobson data. It cannot be excluded, that the satellite data may be responsible for the trend.

Koehler, U.↗
NASA NTRS1994

Deformation of the total ozone content field in the tropical zone

Presented are the ozone investigation results obtained in the tropical zone. Measurements of the total ozone content (TOC) were carried out by the ozonometer M-124. The ozonometer was automated to investigate the ozone intradiurnal variations and to increase precision of the TOC measurements. Obtained results allowed us to follow the effect of tropical cyclones (TC) on the TOC field. Several days before the TC formation the TOC increase is observed in daily mean course compared with the background one. Three types of trend can be singled out in the TOC intradiurnal course: zero, parabolic, quasi-linear. Maximum velocities of a trend are observed some days before the TC formation. Analogous harmonic constituents are mainly presented as spectrum of daily means of ozone, mean and absolute velocities of trend and dispersion as well as spectra of meteorological, hydrometeorological and actinometric values. Revealed is a number of day-to-day ozone variations concerned with large-scale circulations; moisture content in the atmosphere. Obtained are the data about short-period ozone waves (period less than a day). Thin-film silver sensors were used to measure the vertical ozone distribution (VOD). Atmospheric aerosol and VOD measurements were carried out simultaneously, they gave data of the VOD layered structure, where the VOD local minima coincided with the position of aerosol layers' maxima.

Vasilyev, Victor I.↗