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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Exhaust emission survey of an F100 afterburning turbofan engine at simulated altitude flight conditions

Emissions of carbon monoxide, total oxides of nitrogen, unburned hydrocarbons, and carbon dioxide from an F100, afterburning, two spool turbofan engine at simulated flight conditions are reported. For each flight condition emission measurements were made for two or three power levels from intermediate power (nonafterburning) through maximum afterburning. The data showed that emissions vary with flight speed, altitude, power level, and radial position across the nozzle. Carbon monoxide emissions were low for intermediate power (nonafterburning) and partial afterburning, but regions of high carbon monoxide were present downstream of the flame holder at maximum afterburning. Unburned hydrocarbon emissions were low for most of the simulated flight conditions. The local NOX concentrations and their variability with power level increased with increasing flight Mach number at constant altitude, and decreased with increasing altitude at constant Mach number. Carbon dioxide emissions were proportional to local fuel air ratio for all conditions.

Moss, J. E.↗
NASA NTRS1974

Measurement of gaseous emissions from a turbofan engine at simulated altitude conditions

Gaseous emission from a TFE 731-2 turbofan engine were measured over a range of fuel-air ratios from idle to full power at simulated from near sea level to 13,200 m. Carbon monoxide and unburned hydrocarbon emissions were highest at idle and lowest at high power settings; oxides of nitrogen exhibited the reverse trend. Carbon monoxide and unburned hydrocarbon levels decreased with increasing altitude. Oxides of nitrogen emissions were successfully correlated by a parametric group of combustor operating variables.

Diehl, L. A.↗
NASA NTRS1947

Simulated Altitude Performance of Combustors for the 24C Jet Engine: 24C-4 Combustor - 2

The performance of a 24C-4 combustor was investigated with three different combustor baskets and five modifications of these baskets at conditions simulating static (zero-ram) operation of the 24C jet engine over ranges of altitude and engine speed to determine and improve the altitude operational limits of the 24C combustor. Information was also obtained regarding combustion characteristics, the fuel-flow characteristics of the fuel manifolds, and the combustor total-pressure drop. NACA modifications, which consisted of blocking rows of holes on the baskets, increased the minimum point on the altitude-operational-limit curve, which occurs at low engine speeds, for a narrow-upstream-end basket by 8000 feet (from 23, 000 to 31,000 ft_ and for a wide-upstream-end basket by 21,000 feet (from 12, 000 to 34,000 ft). These improvements were approximately maintained over the entire range of engine speeds investigated.

Bernardo, Everett↗
NASA NTRSDate not supplied

Ice Crystal Icing Investigation on a Honeywell Uncertified Research Engine in an Altitude Simulation Icing Facility

A Honeywell Uncertified Research Engine was exposed to various ice crystal conditions in the NASA Glenn Propulsion Systems Laboratory. Simulations using NASA's 1D Icing Risk Analysis tool were used to determine potential inlet conditions that could lead to ice crystal accretion along the inlet of the core flowpath and into the high pressure compressor. These conditions were simulated in the facility to develop baseline conditions. Parameters were then varied to move or change accretion characteristics. Data were acquired at altitudes varying from 5 kft to 45 kft, at nominal ice particle Median Volumetric Diameters from 20 µm to 100 µm, and total water contents of 1 g/m3 to 12 g/m3. Engine and flight parameters such as fan speed, Mach number, and inlet temperature were also varied. The engine was instrumented with total temperature and pressure probes. Static pressure taps were installed at the leading edge of the fan stator, front frame hub, the shroud of the IGV, and first two rotors. Metal temperatures were acquired for vane stators 1-2. In-situ measurements of the particle size distribution were acquired three meters upstream of the engine forward fan flange and one meter downstream of the fan in the bypass in order to study particle break-up behavior. Cameras were installed in the engine to capture ice accretions at the leading edge of the fan stator, splitter lip, and inlet guide vane. Additional measurements acquired but not discussed in this paper include: high speed pressure transducers installed at the trailing edge of the first stage rotor and light extinction probes used to acquire particle concentrations at the fan exit stator plane and at the inlet to the core and bypass. The goal of this study was to understand key parameters of accretion, acquire particle break-up data aft of the fan, and generate a unique icing dataset for model and tool development. This work described in the paper focuses on the effect of particle break-up. It was found that there was significant particle break-up downstream of the fan in the bypass especially with larger initial particle sizes. The metal temperatures on the inlet guide vanes and stators show a temperature increase with increasing MVD. Accretion behavior was very similar across all test cases. However at the inlet guide vanes, the accretion decreased with increasing particle size.

Ashlie B Flegel↗
NASA NTRS2021

Ice-Crystal Icing Investigation on a Honeywell Uncertified Research Engine in an Altitude Simulation Icing Facility

A Honeywell Uncertified Research Engine was exposed to various ice-crystal conditions in the NASA Propulsion Systems Laboratory (PSL). Simulations using NASA's one-dimensional (1D) Icing Risk Analysis tool were used to determine potential inlet conditions that could lead to ice-crystal accretion along the inlet of the core flowpath and into the high-pressure compressor. Baseline conditions were established, and parameters were varied to observe accretion characteristics. Data were acquired at altitudes varying from 5 kft to 45 kft, at nominal ice particle median volumetric diameters from 20 µm to 100 µm, and total water contents of 1 g/m3 to 12 g/m3. Metal temperatures were acquired for the inlet guide vane and vane stators 1–2. In situ measurements of the particle size distribution were acquired upstream and downstream of the engine fan face in order to study particle breakup behavior. Cameras were installed in the engine to capture ice accretions at the leading edge of the fan stator, splitter lip, and inlet guide vane. The goal of this study was to understand the key parameters of accretion, acquire particle breakup data aft of the fan, and generate a unique icing dataset for model development. Significant particle breakup downstream of the fan in the bypass was observed. The metal temperatures on the inlet guide vanes (IGVs) and stators show a temperature increase with increasing particle size. Accretion behavior at the fan stator and splitter lip across was very similar. However, accretion decreased with increasing particle size at the IGVs.

Ashlie B. Flegel↗
NASA NTRS1978

Fluid-electrolyte shifts and maximal oxygen uptake in man at simulated altitude /2,287 m/

Experiments were conducted on six trained distance runners (21-23 yr) subjected to an eight-day dietary control at sea level, followed by an eight-day stay in an altitude chamber (2287-m altitude) and a four-day recovery at sea level. Fluid and electrolyte shifts during exercise at altitude were evaluated to gain insight into the mechanism of reduction in working capacity. The results are discussed in terms of resting fluid volumes and blood constituents, maximal exercise variables, and maximal exercise fluid-electrolyte shifts. Since there are no significant changes in fluid balance or resting plasma volume (PV) at altitude, it is concluded that neither these nor the excessive PV shifts with exercise contribute to the reduction in maximal oxygen uptake at altitude. During altitude exposure the percent loss in PV is found to follow the percent reduction in maximal oxygen uptake; however, on the first day of recovery the percent change in PV remains depressed while maximal oxygen uptake returns to control levels.

Greenleaf, J. E.↗
NASA NTRS1987

The visual control of simulated altitude

The ability of a subject flying an experimental flight to use the different sources of visual information by looking at the vertical tracking error was investigated using a 3 (altitude) x 3 (texture) x 2 (replication) factorial design. Each subject flew these 18 flights in the same partially counterbalanced order, constructed such that there was one flight at each of the three altitudes, and over each of the three surface textures within each successive set of three flights. The three ground-surface textures used consisted of meridian, latitudinal, and square textures described by Wolpert et al. (1983). The results showed that, in displays where only splay information was available, the subjects tended to confuse lateral motion with vertical.

Johnson, Walter W.↗
NASA NTRS1950

Simulated altitude performance of two annular combustors with continuous axial openings for admission of primary air

Methods of introducing and distributing air and fuel in turbojet-engine combustors were evaluated with two fuels, AN-F-32 and AN-F-58. Investigations were made with two single-annulus liners in a one-quarter sector of a 25 1/2-inch-diameter turbojet combustor. Altitude performance data for these combustors are compared with existing data for a production-model double-annulus combustor. Altitude operating limits and combustion efficiencies of both single-annulus combustors were considerably higher than those of the double-annulus combustor; combustion efficiencies were insensitive to changes in fuel-air ratio.

COMBUSTION - TURBINE ENGINES↗
NASA NTRS1950

Starting of rocket engine at conditions of simulated altitude using crude monoethylaniline and other fuels with mixed acid

Experiments were conducted at sea level and pressure altitude of about 55,000 feet at various temperatures to determine starting characteristics of a commercial rocket engine using crude monoethylaniline and other fuels with mixed acid. With crude monoethylaniline, ignition difficulties were encountered at temperatures below about 20 degrees F. With mixed butyl mercaptans, water-white turpentine, and x-pinene, no starting difficulties were experienced at temperatures as low as minus 74 degrees F. Turpentine and x-pinene, however, sometimes left deposits on the injector face. With blends containing furfuryl alcohol and with other blends, difficulties were experienced either from appreciable deposits or from starting.

COMBUSTION - ROCKET ENGINES↗
NASA NTRS1997

Ventilation during simulated altitude, normobaric hypoxia and normoxic hypobaria

To investigate the possible effect of hypobaria on ventilation (VE) at high altitude, we exposed nine men to three conditions for 10 h in a chamber on separate occasions at least 1 week apart. These three conditions were: altitude (PB = 432, FIO2 = 0.207), normobaric hypoxia (PB = 614, FIO2 = 0.142) and normoxic hypobaria (PB = 434, FIO2 = 0.296). In addition, post-test measurements were made 2 h after returning to ambient conditions at normobaric normoxia (PB = 636, FIO2 = 0.204). In the first hour of exposure VE was increased similarly by altitude and normobaric hypoxia. The was 38% above post-test values and end-tidal CO2 (PET(CO2) was lower by 4 mmHg. After 3, 6 and 9 h, the average VE in normobaric hypoxia was 26% higher than at altitude (p < 0.01), resulting primarily from a decline in VE at altitude. The difference between altitude and normobaric hypoxia was greatest at 3 h (+ 39%). In spite of the higher VE during normobaric hypoxia, the PET(CO2) was higher than at altitude. Changes in VE and PET(CO2) in normoxic hypobaria were minimal relative to normobaric normoxia post-test measurements. One possible explanation for the lower VE at altitude is that CO2 elimination is relatively less at altitude because of a reduction in inspired gas density compared to normobaric hypoxia; this may reduce the work of breathing or alveolar deadspace. The greater VE during the first hour at altitude, relative to subsequent measurements, may be related to the appearance of microbubbles in the pulmonary circulation acting to transiently worsen matching. Results indicate that hypobaria per se effects ventilation under altitude conditions.

NASA Discipline Environmental Health↗
NASA NTRS1947

Simulated Altitude Investigation of Stewart-Warner Model 906-B Combustion Heater

An investigation has been conducted to determine thermal and pressure-drop performance and the operational characteristics of a Stewart-Warner model 906-B combustion heater. The performance tests covered a range of ventilating-air flows from 500 to 3185 pounds per hour, combustion-air pressure drops from 5 to 35 inches of water, and pressure altitudes from sea level to 41,000 feet. The operational characteristics investigated were the combustion-air flows for sustained combustion and for consistent ignition covering fuel-air ratios ranging from 0.033 to 0.10 and pressure altitudes from sea level to 45,000 feet. Rated heat output of 50,000 Btu per hour was obtained at pressure altitudes up to 27,000 feet for ventilating-air flows greater than 800 pounds per hour; rated output was not obtained at ventilating-air flow below 800 pounds per hour at any altitude. The maximum heater efficiency was found to be 60.7 percent at a fuel-air ratio of 0.050, a sea-level pressure altitude, a ventilating-air temperature of 0 F, combustion-air temperature of 14 F, a ventilating-air flow of 690 pounds per hour, and a combustion-air flow of 72.7 pounds per hour. The minimum combustion-air flow for sustained combustion at a pressure altitude of 25,000 feet was about 9 pounds per hour for fuel-air ratios between 0.037 and 0.099 and at a pressure altitude of 45,000 feet increased to 18 pounds per hour at a fuel-air ratio of 0.099 and 55 pounds per hour at a fuel-air ratio of 0.036. Combustion could be sustained at combustion-air flows above values of practical interest. The maximum flow was limited, however, by excessively high exhaust-gas temperature or high pressure drop. Both maximum and minimum combustion-air flows for consistent ignition decrease with increasing pressure altitude and the two curves intersect at a pressure altitude of approximately 25,000 feet and a combustion-air flow of approximately 28 pounds per hour.

Ebersbach, Frederick R.↗