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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

High Resolution RANS Nonlinear Harmonic Study of Stage 67 Tip Injection Physics

Numerical prediction of the Stage 67 transonic fan stage employing wall jet tip injection flow control and study of the physical mechanisms leading to stall suppression and stability enhancement afforded by endwall recirculation/injection is the focus of this paper. Reynolds averaged Navier–Stokes (RANS) computations were used to perform detailed analysis of the Stage 67 configuration experimentally tested at NASA's Glenn Research Center in 2004. Time varying predictions of the stage plus recirculation and injection flowpath were executed utilizing the nonlinear harmonic (NLH) approach. Significantly higher grid resolution per passage was achieved than what has been generally employed in prior reported numerical studies of spike stall phenomena in transonic compressors. This paper focuses on characterizing the physics of spike stall embryonic stage phenomena and the influence of tip injection, resulting in experimentally and numerically demonstrated stall suppression.

Engineering↗
NASA NTRS1985

A dual frequency microstrip antenna for Ka band

For fixed satellite communication systems at Ka band with downlink at 17.7 to 20.2 GHz and uplink at 27.5 to 30.0 GHz, the focused optics and the unfocused optics configurations with monolithic phased array feeds have often been used to provide multiple fixed and multiple scanning spot beam coverages. It appears that a dual frequency microstrip antenna capable of transmitting and receiving simultaneously is highly desirable as an array feed element. This paper describes some early efforts on the development and experimental testing of a dual frequency annular microstrip antenna. The antenna has potential application for use in conjunction with a monolithic microwave integrated circuit device as an active radiating element in a phased array of phased array feeds. The antenna is designed to resonate at TM sub 12 and TM sub 13 modes and tuned with a circumferential microstrip ring to vary the frequency ratio. Radiation characteristics at both the high and low frequencies are examined. Experimental results including radiating patterns and swept frequency measurements are presented.

Lee, R. Q.↗
NASA NTRS1996

A Surrogate Approach to the Experimental Optimization of Multielement Airfoils

The incorporation of experimental test data into the optimization process is accomplished through the use of Bayesian-validated surrogates. In the surrogate approach, a surrogate for the experiment (e.g., a response surface) serves in the optimization process. The validation step of the framework provides a qualitative assessment of the surrogate quality, and bounds the surrogate-for-experiment error on designs "near" surrogate-predicted optimal designs. The utility of the framework is demonstrated through its application to the experimental selection of the trailing edge ap position to achieve a design lift coefficient for a three-element airfoil.

Otto, John C.↗
DOE OSTI2023

Performance assessment of a real water source heat pump within a hardware-in-the-loop (HIL) testing environment

Over the last decade, the global fight against climate change through electrification has led to an increase in research on building heating, ventilation, and air conditioning (HVAC) systems that utilize intelligent control algorithms to provide demand-side grid service while also maintaining the thermal comfort of building occupants. As the pivotal point between building electricity consumption and indoor thermal comfort, high-efficiency electrical vapor-compression heat pumps are at the center of these emerging studies, and various grid-interactive and occupant-comfort control algorithms have been developed for them. The impact of these algorithms on heat pump operation and performance when subjected to different weather conditions, building loads, and grid requests calls for investigation and verification via experimental testing with actual heat pumps integrated with real-time building and grid responses. This study introduces a Water-Source Heat Pump (WSHP) Hardware-in-The-Loop (HIL) Test Facility that is the first of its kind. This testbed utilizes a 2-ton variable speed water-to-air heat pump that is capable of interacting with a virtual environment currently comprised of an EnergyPlus (E+) building simulation, an agent-based occupant behavioral model, and a single U-tube ground-loop heat exchanger (GLHE) model. Detailed descriptions of the testbed’s physical design and operation, virtual environment, as well as their mutual communication is provided. An uncertainty analysis is also performed under manufacturer specified heating and cooling design conditions. This analysis shows that the total load across the WSHP’s demand side heat exchanger, i.e., the sum of its latent and sensible components, can be measured with a relative uncertainty of ± 10.4% and ± 3.6% in cooling and heating mode respectively. The WSHP’s coefficient of performance (COP) can be measured with relative uncertainties of ± 10.4% in cooling mode, and ± 3.7% in heating mode. A preliminary 24-h experimental demonstration is then performed utilizing the DOE prototype small commercial office building model in E+. The simulation takes place in Atlanta, GA on the date of 08/26/15 from 12:00 AM to 11:59 PM using TMY3 weather data. Here, the results from this demonstration show that over the course of this experiment the simulated outputs of zone dry-bulb temperature, zone humidity ratio, and WSHP inlet water temperature can be tracked by testbed emulators up to a root mean squared error (RMSE) of ± 0.27 °C, ± 0.376 g/kg, and ± 0.85 °C respectively. The WSHP’s dynamic behavioral characteristics and performance are also captured, and correspond well with the authors’ previous understanding of heat pump efficiency as a function of evaporator and condenser fluid inlet conditions respectively.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS2001

Wind Code Application to External Forebody Flowfields with Comparisons to Experimental Results

The WIND Code, a general purpose Navier-Stokes solver, has been utilized to obtain supersonic external flowfield Computational Fluid Dynamics (CFD) solutions over an axisymmetric, parabolic forebody with comparisons made to wind tunnel experimental results. Various cases have been investigated at supersonic freestream conditions ranging from Mach 2.0 to 3.5, at 0 deg and 3 deg angles-of-attack, and with either a sharp-nose or blunt-nose forebody configuration. Both a turbulent (Baldwin-Lomax algebraic turbulence model) and a laminar model have been implemented in the CFD. Obtaining the solutions involved utilizing either the parabolized- or full-Navier-Stokes analyses supplied in WIND. Comparisons have been made with static pressure measurements, with boundary-layer rake and flowfield rake pitot pressure measurements, and with temperature sensitive paint experimental results. Using WIND's parabolized Navier-Stokes capability, grid sequencing, and the Baldwin-Lomax algebraic turbulence model allowed for significant reductions in computational time while still providing good agreement with experiment. Given that CFD and experiment compare well, WIND is found to be a good computational platform for solving this type of forebody problem, and the grids developed in conjunction with it will be used in the future to investigate varying freestream conditions not tested experimentally.

Frate, F. C.↗
NASA NTRS2008

L1 Adaptive Control Law for Flexible Space Launch Vehicle and Proposed Plan for Flight Test Validation

This paper explores application of the L1 adaptive control architecture to a generic flexible Crew Launch Vehicle (CLV). Adaptive control has the potential to improve performance and enhance safety of space vehicles that often operate in very unforgiving and occasionally highly uncertain environments. NASA s development of the next generation space launch vehicles presents an opportunity for adaptive control to contribute to improved performance of this statically unstable vehicle with low damping and low bending frequency flexible dynamics. In this paper, we consider the L1 adaptive output feedback controller to control the low frequency structural modes and propose steps to validate the adaptive controller performance utilizing one of the experimental test flights for the CLV Ares-I Program.

Kharisov, Evgeny↗
DOE OSTI2018

Theoretical and Experimental Studies of CoGa Catalysts for the Hydrogenation of CO 2 to Methanol

We report methanol is an important chemical compound which is used both as a fuel and as a platform molecule in chemical production. Synthesizing methanol, as well as dimethyl ether, directly from carbon dioxide and hydrogen produced using renewable electricity would be a major step forward in enabling an environmentally sustainable economy. We utilize density functional theory combined with microkinetic modeling to understand the methanol synthesis reaction mechanism on a model CoGa catalyst. A series of catalysts with varying Ga content are synthesized and experimentally tested for catalytic performance. The performance of these catalysts is sensitive to the Co:Ga ratio, whereby increased Ga content results in increased methanol and dimethyl ether selectivity and increased Co content results in increased selectivity towards methane. We find that the most active catalysts have up to 95% CO-free selectivity towards methanol and dimethyl ether during CO 2 hydrogenation and are comparable in performance to a commercial CuZn catalyst. Finally, using in situ DRIFTS we experimentally verify the presence of a surface formate intermediate during CO 2 hydrogenation in support of our theoretical calculations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2010

NASA MUST Paper: Infrared Thermography of Graphite/Epoxy

The focus of this project is to use Infrared Thermography, a non-destructive test, to detect detrimental cracks and voids beneath the surface of materials used in the space program. This project will consist of developing a simulation model of the Infrared Thermography inspection of the Graphite/Epoxy specimen. The simulation entails finding the correct physical properties for this specimen as well as programming the model for thick voids or flat bottom holes. After the simulation is completed, an Infrared Thermography inspection of the actual specimen will be made. Upon acquiring the experimental test data, an analysis of the data for the actual experiment will occur, which includes analyzing images, graphical analysis, and analyzing numerical data received from the infrared camera. The simulation will then be corrected for any discrepancies between it and the actual experiment. The optimized simulation material property inputs can then be used for new simulation for thin voids. The comparison of the two simulations, the simulation for the thick void and the simulation for the thin void, provides a correlation between the peak contrast ratio and peak time ratio. This correlation is used in the evaluation of flash thermography data during the evaluation of delaminations.

Comeaux, Kayla↗
NASA NTRS1996

Computational Modeling and Validation for Hypersonic Inlets

Hypersonic inlet research activity at NASA is reviewed. The basis for the paper is the experimental tests performed with three inlets: the NASA Lewis Research Center Mach 5, the McDonnell Douglas Mach 12, and the NASA Langley Mach 18. Both three-dimensional PNS and NS codes have been used to compute the flow within the three inlets. Modeling assumptions in the codes involve the turbulence model, the nature of the boundary layer, shock wave-boundary layer interaction, and the flow spilled to the outside of the inlet. Use of the codes and the experimental data are helping to develop a clearer understanding of the inlet flow physics and to focus on the modeling improvements required in order to arrive at validated codes.

Povinelli, Louis A.↗
DOE OSTI2021

Experimental Investigation of Mercury's Magma Ocean Viscosity: Implications for the Formation of Mercury's Cumulate Mantle, Its Subsequent Dynamic Evolution, and Crustal Petrogenesis

Mercury has a compositionally heterogeneous surface that was produced by different periods of igneous activity during Mercury’s history, perhaps suggesting heterogeneous mantle sources. Furthermore, understanding the structure of Mercury’s mantle formed during the planet’s magma ocean stage could help in developing a petrologic model for Mercury, and thus, its dynamic history in the context of crustal petrogenesis. We present results of falling sphere viscometry experiments on late stage Mercurian magma ocean analogue compositions. Owing to the presence of sulfur on the surface of Mercury, two compositions were tested, one with sulfur and one without. The liquids have viscosities of 0.6-3.9 (sulfur-bearing) and 0.6-10.9 Pa·s (sulfur-free), similar to an andesite at the tested experimental conditions (1.4-6.2 GPa, 1600-2000°C). We present new viscosity models that enable extrapolation beyond the experimental conditions and evaluate grain growth and the potential for crystal entrainment in a cooling, convecting magma ocean. We consider scenarios with and without a graphite flotation crust, which suggests two possible endmember outcomes for Mercury’s mantle structure. With a graphite flotation crust, crystallization of the mantle would be fractional with negatively buoyant minerals sinking to form a stratified cumulate pile according to the crystallization sequence. Without a flotation crust, crystals would largely remain entrained in the convecting liquid during solidification, producing a homogeneous mantle. In the context of these endmember models, the chemically heterogeneous surface could result from dynamical stirring or mixing of a mantle that was initially compositionally stratified, or from different extents of melting of a homogeneous mantle.

58 GEOSCIENCES↗
NASA NTRS1993

Integrated CFD modeling of gas turbine combustors

3D, curvilinear, multi-domain CFD analysis is becoming a valuable tool in gas turbine combustor design. Used as a supplement to experimental testing. CFD analysis can provide improved understanding of combustor aerodynamics and used to qualitatively assess new combustor designs. This paper discusses recent advancements in CFD combustor methodology, including the timely integration of the design (i.e. CAD) and analysis (i.e. CFD) processes. Allied Signal's F124 combustor was analyzed at maximum power conditions. The assumption of turbulence levels at the nozzle/swirler inlet was shown to be very important in the prediction of combustor exit temperatures. Predicted exit temperatures were compared to experimental rake data, and good overall agreement was seen. Exit radial temperature profiles were well predicted, while the predicted pattern factor was 25 percent higher than the harmonic-averaged experimental pattern factor.

Fuller, E. J.↗
NASA NTRS1981

Numerical Simulation of Three-Dimensional Boattail Afterbody Flowfields

The thin shear-layer approximations of the three-dimensional, compressible Navier-Stokes equations are solved for subsonic, transonic, and supersonic now over axisymmetric boattail bodies at moderate angles of attack. The plume is simulated by a solid body configuration identical to those used In experimental tests. An implicit algorithm of second-order accuracy is used to solve the equations on the ILLIAC 4 computer. The turbulence is expressed by an algebraic model applicable to three-dimensional flowfields with moderate separation. The formulation used is attractive in its independence of boundary-layer parameters. Such a simple model, however, is incapable of supporting detailed quantitative descriptions of complex shear flows. Never-the-less, good qualitative comparisons are found with three different sets of experimental date. Quantitative improvement will depend on improved turbulence transport descriptions.

Deiwert, G. S.↗
DOE OSTI2017

Hybrid Membrane-based Ionic Liquid Absorption Cycle for Water Heating, Dehumidification, and Cooling

To meet the growing energy consumption and mitigate climate concerns, novel energy efficient technologies need to be developed. Water heating, dehumidification and space cooling form a significant percentage (~24%) of a typical U.S. household energy consumption and a total of 2.6 quad of primary energy consumption. In this paper, we present a novel system for combined water heating, dehumidification, and space cooling. The three processes can be achieved by one device using a novel semi-open absorption based system combined with evaporative cooling. The absorption based system absorbs water vapor from its ambient. The latent heat of absorption, released into the absorbent, is transferred into the process water that cools the absorbent. The water absorbed is later released in the desorber through heating, and the water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water vapor can either be drained if dehumidification is desired or be used in an evaporative cooling process for space cooling. The major innovations that enable such an absorption-based device are demonstrated in this study through an experimental test setup. First, a membrane based absorption system in a compact and scalable platform is used to alleviate the liquid entrainment issue encountered in the conventional packed bed absorbers. Second, architecture reconfigurations, like novel fluid circuits and semi-open absorption system are deployed to enhance performance and lower system cost. Finally, an ionic liquid is implemented to minimize corrosion and eliminate crystallization risks, a major concern with conventional salts. The water heating and dehumidification component of the device are experimentally evaluated and the device is characterized for various system parameters. A water heating COP of 1.4 is achieved in this first generation prototype. These innovations pave the way for a compact, efficient, and low cost absorption based system for residential scale applications.

CHUGH, Devesh↗
DOE OSTI2019

Impact Behavior of Polyester GFRP for Naval Applications: Influence of the Clamping Device and Fluid–Material Interaction

The low-velocity impact behavior of polyester glass fiber composite laminates has been investigated under different clamping conditions, by wetting the specimens surface with fluids having different densities. Unidirectional composite laminates, based on polymer resin and fibers of naval interest, with different thicknesses have been manufactured by resin transfer molding process in order to have a high control of the final properties and a high fiber volume fraction. Impact tests in air have been, first, performed up to penetration on all manufactured composites having four different thicknesses to get information on the material impact behavior. The effect of the clamping conditions and the interaction of the laminates with two fluids different in density, i.e., water and paraffin oil, have been investigated, then, only on the thickest laminates that showed a lower tendency to impact damage. In particular, the impact tests have been performed by impacting the front surface of the sample and by wetting the back surface of the composite samples under unclamped and clamped conditions, replicating the boundary constraints suggested by ASTM D7136 Standard for the conventional impact tests. Experimental results showed a lower initial rigidity, higher absorbed energy and deflection for specimens exposed to liquids with respect to those exposed to air, confirming the need of taking into account the fluid interaction in the case of marine composite applications.

36 MATERIALS SCIENCE↗
NASA NTRS2014

Deployable Fresnel Rings

Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the relative strength of power coupling between the first and second microstrip antennas with and without the DFR. Typically, a DFR is designed for use at a particular frequency; however, testing of a DFR indicated a relatively wide operational bandwidth of approximately 8.2%. Wider bandwidth operation and multi-band operation are anticipated by extending the known art of conventional Fresnel rings to the DFRs. Increasing the number of rings used to construct a DFR antenna increases the gain, with the upper bound limited often by the largest practical dimensions that can be tolerated for a given application. The maximum theoretical improvement in gain for a single ring is 9.5 dB. Experimental results are within 0.9 dB of this theoretical value. Adding rings increases gain, and theoretically, improvements of 10 to 13 dB above that of the primary antenna gain can be achieved with two- and three-ring versions.

Kennedy, Timothy F.↗
DOE OSTI2023

Design Improvements in Liquid Argon Purification Techniques in DUNE Cold Electronics Test Cryostat (Iceberg)

A proposed design improvement for the removal of electronegative impurities from liquid argon for the purpose of neutrino detector research is described. The design will utilize a commercially available submersible pump to circulate liquid argon through an external filter containing molecular sieve and activated copper media, removing water and oxygen, respectively. The existing state-of-the-art filter design provides a throughput of 0.5 L/min, while the capacity of the submersible pump design is at least 4 L/min, though could be even higher depending on total losses within the filtration piping assembly. An additional benefit of the new design will be the ability to regenerate the filter media in situ without stopping the experimental testing. The following work will describe the design, operation, and expected performance using CFD analysis.

Schwartz, F.↗
DOE OSTI2020

Building fault detection data to aid diagnostic algorithm creation and performance testing

It is estimated that approximately 4-5% of national energy consumption can be saved through corrections to existing commercial building controls infrastructure and resulting improvements to efficiency. Correspondingly, automated fault detection and diagnostics (FDD) algorithms are designed to identify the presence of operational faults and their root causes. A diversity of techniques is used for FDD spanning physical models, black box, and rule-based approaches. A persistent challenge has been the lack of common datasets and test methods to benchmark their performance accuracy. This article presents a first of its kind public dataset with ground-truth data on the presence and absence of building faults. This dataset spans a range of seasons and operational conditions and encompasses multiple building system types. It contains information on fault severity, as well as data points reflective of the measurements in building control systems that FDD algorithms typically have access to. The data were created using simulation models as well as experimental test facilities, and will be expanded over time.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Nonexcitonic mechanism for electronic and structural phase transitions in Ta 2 ⁢Ni⁢(Se,S) 5

Here, we present a first-principles study based on density functional theory (DFT) on the electronic and structural properties of Ta 2 NiSe 5 , a layered transition metal chalcogenide that has been considered as a possible candidate for an excitonic insulator. Our systematic DFT results however provide a nonexcitonic mechanism for the experimentally observed electronic and structural phase transitions in Ta 2 NiSe 5 , in particular explaining why sulfur substitution of selenium reduces the distortion angle in the low-temperature phase and potassium dosing closes the gap in the electronic structure. Moreover, the calculations show that these two effects couple to each other. Further, our first-principles calculations predict several changes in both the crystal structure and electronic structure under the effects of uniform charge dosing and uniaxial strain, which could be tested experimentally.

Tang, Weichen [University of California, Berkeley,↗