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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 1,657 records · Page 92

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NASA NTRS1961

Investigation of Net-Thrust and Base-Pressure Characteristics of Cylindrical Afterbodies with Clustered Supersonic Nozzles at Transonic Mach Numbers

A wind-tunnel investigation has been conducted at Mach numbers from 0.9 to 1.4 to determine the net-thrust and base-pressure characteristics of cylindrical afterbodies having clustered supersonic nozzles. The design Mach numbers of the nozzles were 2.0 and 2.5 and the number of clustered nozzles ranged from two to six. The nozzles had throat-to- base diameter ratios of 0.155, 0.225, 0.278, and 0.320. Some models were tested with various configurations of extended, shrouded, flush, and canted nozzles. The nozzles discharged unheated air from the base at ratios of jet total pressure to free-stream static pressure ranging from 1 to approximately 20. The results of this investigation showed that both the ratio of total exit area to base area and the number of jets affect the net-thrust factor to a significant degree for the extended-nozzle configurations. Good net-thrust factors were obtained with all the model configurations near the design jet total-pressure ratio; however, the extended-nozzle configuration had the highest net-thrust factor over the test jet total- pressure-ratio range. Canting the twin nozzles outward resulted in a favorable thrust factor over a limited jet total-pressure-ratio range, and surrounding the nozzles with a single shroud reduced thrust factors for the range of jet total-pressure ratio of this investigation.

Andrews, Earl H., Jr.↗

NASA NTRSDate not supplied

CFD Simulations of Landing and Takeoff CRM High-Lift Configurations

Numerical simulations have been performed for a conventional high-lift version of the Common Research Model (CRM) model corresponding to landing and take- off configurations. Computed values of lift and drag for the landing configuration are compared with the experimental data acquired in the 14- by 22-Foot Subsonic Tunnel (14×22) at the NASA Langley Research Center (LaRC). Simulations replicated the experimentally observed improvements in the lift characteristics in the presence of a nacelle chine. Flow visualization images indicate that vortices generated by the nacelle chine reduce flow separation regions on the upper surface of the wing at higher angles of attack. Based on such observations, the take-off configuration considered is also equipped with a nacelle chine, and testing of this configuration is planned in the 14×22 tunnel in near future. Preliminary solutions are also presented to explore the feasibility of using a localized flap gap blowing (LFGB) active flow control concept for improving the aerodynamic performance at take-off conditions.

aerodynamics↗

NASA NTRSDate not supplied

CFD Simulations of Landing and Takeoff CRM High-Lift Configurations

aerodynamics↗

DOE OSTI2024

Development of a rate-based ENRTL-RK process model for a water-lean solvent

Advanced water-lean solvents (WLS) for post-combustion CO2 capture offer several advantages over the aqueous amine solvents . WLS have lower parasitic energy penalty, lower corrosion, lower temperature and high-pressure CO2 regeneration leading to lower cost of CO2 capture. RTI International, with funding from the US Department of Energy, has been developing its novel water-lean solvent, that has shown specific reboiler duty of 2.3 GJ/t-CO2 at the 60-kWe pilot testing unit (Tiller Plant, SINTEF, Norway) and 2.6 GJ/t-CO2 at the engineering scale testing system (12 MWe) at the Technology Centre Mongstad (TCM) in Norway. All heat duties, including the one from TCM testing, were consistent with Aspen Plus modeling of the specific configuration of each test plant. This work focuses on the development of a detailed process model using in-house laboratory measurements and process data at pilot scale. The eNTRL-RK model used in this work is based on an unsymmetric activity coefficient model with the reference states chosen to be pure liquids for solvents and ideal dilute solution at unit solute molality (resulting in activity coefficient of unity at infinite dilution) for electrolytes. It uses the Redlich-Kwong equation of state for vapor phase properties and Henry’s law for solubility of supercritical gases. The model was validated using process data from the pilot-scale campaign at the Tiller plant, and the engineering scale test campaign at TCM. Data on CO2 capture rate, absorber, and regenerator temperature profiles and specific reboiler duties from two different test campaigns at Tiller and TCM, were used to further refine and validate the model and the model compares favorably to experimental data. The validation results against TCM campaign will be presented in this work.

CO2 capture↗

NASA NTRS1976

Aeroheating (pressure) characteristics on a 0.10-scale version of the vehicle 3 space shuttle configuration (26-OTS) in the Langley Research Center 4-foot wind tunnel (IH4)

Results of wind tunnel tests, conducted at the Langley Research Center Unitary Plan Wind Tunnel, are presented. The model tested was an 0.010-scale version of the Vehicle 3 Space Shuttle Configuration. Pressure measurements were made on the launch configuration, Orbiter alone, external tank alone, and solid rocket booster alone, to provide heat transfer pressure data. The tests were conducted for a Mach number range from 2.36 to 4.6 and Reynolds number range from 1.2 to 5 million per foot. The model was tested at angles of attack from -10 to 20 deg for a sideslip angle range from -5 to +5 deg, and at sideslip angles from -5 to 48 deg for 0 deg angle of attack. Tabulated data are given and photographs of the test configuration are shown.

Kingsland, R. B.↗

NASA NTRS2013

Process Optimization of Bismaleimide (BMI) Resin Infused Carbon Fiber Composite

Bismaleimide (BMI) resins are an attractive new addition to world-wide composite applications. This type of thermosetting polyimide provides several unique characteristics such as excellent physical property retention at elevated temperatures and in wet environments, constant electrical properties over a vast array of temperature settings, and nonflammability properties as well. This makes BMI a popular choice in advance composites and electronics applications [I]. Bismaleimide-2 (BMI-2) resin was used to infuse intermediate modulus 7 (IM7) based carbon fiber. Two panel configurations consisting of 4 plies with [+45deg, 90deg]2 and [0deg]4 orientations were fabricated. For tensile testing, a [90deg]4 configuration was tested by rotating the [0deg]4 configirration to lie orthogonal with the load direction of the test fixture. Curing of the BMI-2/IM7 system utilized an optimal infusion process which focused on the integration of the manufacturer-recommended ramp rates,. hold times, and cure temperatures. Completion of the cure cycle for the BMI-2/IM7 composite yielded a product with multiple surface voids determined through visual and metallographic observation. Although the curing cycle was the same for the three panellayups, the surface voids that remained within the material post-cure were different in abundance, shape, and size. For tensile testing, the [0deg]4 layup had a 19.9% and 21.7% greater average tensile strain performance compared to the [90deg]4 and [+45deg, 90deg, 90deg,-45degg] layups, respectively, at failure. For tensile stress performance, the [0deg]4 layup had a 5.8% and 34.0% greater average performance% than the [90deg]4 and [+45deg, 90deg, 90deg,-45deg] layups.

Ehrlich, Joshua W.↗

NASA NTRS1993

Correlation of ground tests and analyses of a dynamically scaled Space Station model configuration

Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.

Javeed, Mehzad↗

NASA NTRS1993

Correlation of ground tests and analyses of a dynamically scaled space station model configuration

Javeed, Mehzad↗

NASA NTRS1974

Aerodynamic damping and oscillatory stability of a model of a proposed HL-10 vehicle in pitch at Mach numbers from 0.20 to 2.86 and in YAW at Mach numbers from 0.20 to 1.20

Wind tunnel tests of a proposed HL-10 lifting body vehicle were conducted to determine the subsonic and transonic aerodynamic characteristics. The conditions under which the tests were conducted are described. The tests indicate that the configuration has slightly positive damping in pitch except at higher angles of attack at Mach numbers of 0.8, 0.9, and 1.0. At supersonic speeds, the configuration has positive damping in pitch for all test conditions. At subsonic and transonic speed, the configuration has positive damping and positive stability in yaw for all test conditions.

Kilgore, R. A.↗

NASA NTRS1983

Programming substructure computations for elliptic problems on the CHiP system

A number of studies have been conducted with the aim to apply parallel computation to problems associated with solving finite element equations arising in structural mechanics and fluid dynamics. These studies have provided many important results. The present investigation is concerned with a set of experiments designed to test two ideas, including configurability and substructuring. The considered algorithms and tests are intended for implementation on the Configurable, Highly Parallel (CHiP) family of architecture described by Snyder (1982). The ChiP computer is composed of homogeneous processing elements (PEs) placed at regular intervals in a lattice of programmable switches. Two examples of the role of configurability and substructuring for simple iterative algorithms are considered, giving attention to conjugate gradient iterations, and tridiagonal systems of equations.

Gannon, D.↗

NASA NTRS1988

Computational design of low aspect ratio wing-winglet configurations for transonic wind-tunnel tests

A computational design has been performed for three different low aspect ratio wing planforms fitted with nonplanar winglets; one of the three planforms has been selected to be constructed as a wind tunnel model for testing in the NASA LaRC 7 x 10 High Speed Wind Tunnel. A design point of M = 0.8, CL approx = 0.3 was selected, for wings of aspect ratio equal to 2.2, and leading edge sweep angles of 45 and 50 deg. Winglet length is 15 percent of the wing semispan, with a cant angle of 15 deg, and a leading edge sweep of 50 deg. Winglet total area equals 2.25 percent of the wing reference area. This report summarizes the design process and the predicted transonic performance for each configuration.

Kuhlman, John M.↗

NASA NTRS1958

Aerodynamic Characteristics at a Mach Number of 6.8 of Two Hypersonic Missile Configurations, One with Low-Aspect-Ratio Cruciform Fins and Trailing-Edge Flaps and One with a Flared Afterbody and All-Movable Controls

An investigation has been made to determine the aerodynamic characteristics in pitch at a Mach number of 6.8 of hypersonic missile configurations with cruciform trailing-edge flaps and with all-movable control surfaces. The flaps were tested on a configuration having low-aspect-ratio cruciform fins with an apex angle of 5 deg the all-movable controls were mounted at the 46.7-percent body station on a configuration having a 10 deg flared afterbody. The tests were made through an angle-of-attack range of -2 deg to 20 deg at zero sideslip in the Langley 11-inch hypersonic tunnel. The results indicated that the all-movable controls on the flared afterbody model should be capable of producing much larger values of trim lift and of normal acceleration than the trailing-edge -flap configuration. The flared -after body configuration had considerably higher drag than the cruciform-fin model but only slightly lower values of lift drag ratio.

Robinson, Ross B↗

NASA NTRS1958

Aerodynamic Characteristics at a Mach Number of 6.8 of Two Hypersonic Missile Configurations, One with Low-Aspect-Ratio Cruciform Fins and Trailing-Edge Flaps and One with a Flared Afterbody and All-Movable Controls

An investigation has been made to determine the aerodynamic characteristics in pitch at a Mach number of 6.8 of hypersonic missile configurations with cruciform trailing-edge flaps and with all-movable control surfaces. The flaps were tested on a configuration having low-aspect-ratio cruciform fins with an apex angle of 5 degrees; the all-movable controls were mounted at the 46.7-percent body station on a configuration having a 10 degrees flared afterbody. The tests were made through an angle-of-attack range of -2 degrees to 20 degrees at zero sideslip in the Langley 11-inch hypersonic tunnel. The results indicated that the all-movable controls on the flared-afterbody model should be capable of producing much larger values of trim lift and of normal acceleration than the trailing-edge-flap configuration. The flared-afterbody configuration had considerably higher drag than the cruciform-fin model but only slightly lower values of lift-drag ratio.

Bernot, P. T.↗

NASA NTRS2015

Buoyant Effects on the Flammability of Silicone Samples Planned for the Spacecraft Fire Experiment (Saffire)

Flammability experiments on silicone samples were conducted in anticipation of the Spacecraft Fire Experiment (Saffire). The sample geometry was chosen to match the NASA 6001 Test 1 specification, namely 5 cm wide by 30 cm tall. Four thicknesses of silicone (0.25, 0.36, 0.61 and 1.00 mm) were examined. Tests included traditional upward buoyant flame spread using Test 1 procedures, downward opposed flow flame spread, horizontal and angled flame spread, forced flow upward and downward flame spread. In addition to these configurations, upward and downward tests were also conducted in a chamber with varying oxygen concentrations. In the upward buoyant flame spread tests, the flame generally did not burn the entire sample. As thickness was increased, the flame spread distance decreased before flame extinguishment. For the thickest sample, ignition could not be achieved. In the downward tests, the two thinnest samples permitted the flame to burn the entire sample, but the spread rate was lower compared to the corresponding upward values. The other two thicknesses could not be ignited in the downward configuration. The increased flammability for downward spreading flames relative to upward ones is uncommon. The two thinnest samples also burned completely in the horizontal configuration, as well as at angles up to 75 degrees from the horizontal. The upward and downward flammability behavior was compared in atmospheres of varying oxygen concentration to determine a maximum oxygen concentration for each configuration. Upward tests in air with an added forced flow were more flammable. Complementary analyses using SEM and TGA techniques suggest the importance of the silica layer formed on the burned sample surface. As silicone burns upward, silica deposits downstream •If the silicone is ignited in the downward configuration, it burns the entire length of the sample •Burning upward at an angle increases the burn length in some cases possibly due to less silica deposition •Forced flow in the upward burning case increases flammability, likely due to an increase in convective flow preventing silica from depositing •Samples in upward configuration burning under forced flow self extinguish after forced flow is removed

Flammability↗

NASA NTRS1974

Triple balance test of the PRR baseline space shuttle configuration on a .004 scale model of the MCR 0074 orbiter configuration in the MSFC 14 x 14 inch Trisonic Wind Tunnel (TWT 570) IA31F(B), volume 1

A wind tunnel force and moment test of the space shuttle launch vehicle was conducted. The wind tunnel model utilized a triple balance such that component aerodynamics of the orbiter, external tank, and solid rocket booster was obtained. The test was conducted at an angle of attack range from -10 deg to 10 deg, and angle of sideslip range from -10 deg to 10 deg, and a Mach number range from 0.6 to 4.96. Simulation parameters to be used in future launch vehicle wind tunnel tests were investigated. The following were included: (1) effect of orbiter -ET attach hardware; (2) model attachment (spacer) effects; (3) effects of grit on model leading surfaces; and (4) model misalignment effects. The effects of external tank nose shape was studied by investigating five different nose configurations. Plotted and tabulated data is reported.

Ramsey, P. E.↗

NASA NTRS1980

An experimental investigation of endwall profiling in a turbine vane cascade

Measurements of surface static pressures, flow total pressure loss, and exit air angle were obtained for two linear cascades to establish the effects of endwall profiling. Testing was conducted at an isentropic exit Mach number of 0.85. One cascade was fabricated with planar endwalls while the other had one planar and one profiled endwall. Both cascades utilized the same high pressure turbine inlet guide vane section. It was found that in terms of full passage loss the profiled endwall cascade has the superior performance. The secondary loss results obtained are reasonably well predicted by correlations developed from incompressible flow testing of similar configurations. Inviscid flow and boundary layer calculations are compared with the test data, and overall, the agreement is found to be good. Use of the results for design purposes is briefly discussed.

Kopper, F. C.↗

NASA NTRS1984

The design, fabrication and delivery of a spacelab neutral buoyancy Instrument Pointing System (IPS) mockup

Underwater simulations of EVA contingency operations such as manual jettison, payload disconnect, and payload clamp actuation were used to define crew aid needs and mockup pecularities and characteristics to verify the validity of simulation using the trainer. A set of mockup instrument pointing system tests was conducted and minor modifications and refinements were made. Flight configuration struts were tested and verified to be operable by the flight crew. Tasks involved in developing the following end items are described: IPS gimbal system, payload, and payload clamp assembly; the igloos (volumetric); spacelab pallets, experiments, and hardware; experiment, and hardware; experiment 7; and EVA hand tools, support hardware (handrails and foot restraints). The test plan preparation and test support are also covered.

Vanvalkenburgh, C. N.↗

NASA NTRS1987

Description of a magnetic bearing test fixture

A description of a microcomputer controlled magnetic bearing test fixture is presented. Parameters which are controlled are magnetic bearing current and gaps. Parameters which are measured are magnetic bearing gaps, magnetic flux in the bearing gaps, and bearing forces. The test fixture is configured for bearing elements similar to those used in a laboratory test model Annular Momentum Control Device (AMCD).

Groom, Nelson J.↗