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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

GeoMelt{sup R} In-Container Vitrification (ICV){sup TM} for Fukushima Daiichi Water Treatment Secondary Wastes - 20212

The Japanese government is supporting development work implemented jointly by Veolia subsidiaries Kurion Japan, K.K., Veolia Nuclear Solutions (VNS), Inc., and Veolia Nuclear Solutions Federal Services, LLC for treating radioactive waste generated from Fukushima Daiichi Nuclear Power Station (NPS) water treatment using the GeoMelt{sup TM} In-Container Vitrification (ICV){sup TM} technology. The initial work consisted of glass formulation and engineering-scale testing which was completed in 2018, in the frame of an IRID (International Research Institute for Nuclear Decommissioning) program as part of a project subsidized by Japan's Ministry of Economy, Trade and Industry (METI). The Fukushima Daiichi NPS Mid- and Long-Term Road-map requires investigation of methods to stabilize solid wastes (and to immobilize radioisotopes in the wastes) generated as a result of emergency response and decommissioning activities. Cooling water treatment has resulted in a significant amount of solid and slurry secondary wastes (mostly adsorbents and ion-exchange materials) which will require processing at some point. GeoMelt{sup R} ICV{sup TM} is a joule-heated melter technology which uses a refractory-lined single-use container combining the melter and disposal container. There is no pouring required nor concerns with refractory corrosion which allows the process to accommodate a wide range of waste chemistries and high waste loadings. The testing described here consisted of three engineering-scale melts, each processing between 212 kg and 240 kg of waste simulants, glass formers, and non-radioactive cesium (Cs) and strontium (Sr) tracers. Continuous isokinetic stack sampling of off-gas emissions was performed for each test in order to calculate Cs and Sr retention in the glass wasteform. Single-pass retention of Cs in the final glass wasteform ranged from 91.46 to 99.30%, and single-pass retention of Sr ranged from 99.76 to 100%. Planned particulate recycle will increase these retention levels. Melt 1 processed a mixture of KUR-EH (a zeolite-based ion-exchange material), simulated Advanced Liquid Processing System (ALPS) Carbonate and Iron Slurries, and glass additives. Melt 2 processed a mixture of KUR-EH, KUR-TSG (a titanate-based adsorbent), and glass additives. Melt 3 processed a mixture of KUR-EH, simulated barium sulfate/iron ferrocyanide sludge (AREVA sludge), and glass additives. Waste loadings for these melts ranged from 70 weight percent (wt%) to 82 wt%. Vitrification produces a waste form much denser than the stored water treatment secondary waste wastes, resulting in significant volume reduction. Volume reductions for the three tests ranged from 74 to 79 vol%. Vitrification produces a chemically durable wasteform. Pacific Northwest National Laboratory (PNNL) tested three glass samples from each engineering-scale melt) by the Materials Characterization Center 1 (MCC-1) test, an international standard leach test of the chemical durability of nuclear waste glasses. PNNL also obtained one U.S. reference glass (EA Glass) and two Japan reference glasses P0798) and tested these under the same MCC-1 conditions (90 deg. C, 10 m-1, DIW, and 7, 14, 28-day) as the GeoMelt{sup R} ICV{sup TM} glasses. The GeoMelt{sup R} ICV{sup TM} glasses exhibited lower total normalized releases and 14- to 28-day normalized release rates than the three reference glasses. These results suggest that the GeoMelt{sup R} ICV{sup TM} glasses have durabilities on par with high-level waste glasses under standard test conditions. Post-melt process sampling and analysis indicated no Cs migration into the melter refractory materials and very little deposition of Cs or Sr onto the melter hood or off-gas piping internals. The results of the testing indicated good Cs retention in the glass, high volume reduction and waste loadings, and excellent chemical durability. These factors are important to minimize treatment costs and to protect workers and the environment. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Low-carbon fuels for spark-ignited engines: A comparative study of compressed natural gas and liquefied petroleum gas on a CFR engine with exhaust gas recirculation

Decades of work on low-carbon fuels have established their potential for substantial emissions reductions; however, their adoption is still limited by infrastructure concerns and engine efficiency deficits. As infrastructures have begun to evolve, research on strategies that maximize engine efficiency through interactions with fuel properties must also now take center place. This paper compares the performance, emissions, and combustion characteristics of two forefront low-carbon fuels: compressed natural gas (CNG) and liquefied petroleum gas (LPG) in a cooperative fuel research (CFR) engine over a range of compression ratios and engine loads. The effects of exhaust gas recirculation (EGR), end-gas auto-ignition, and a novel combustion control tool, the combustion intensity metric (CIM), were also evaluated at different stoichiometric engine operating conditions. In comparison to LPG, CNG operation demonstrated an extended knock-free regime, allowing engine operation at higher engine loads and compression ratios, but LPG operation exhibited enhanced combustion characteristics with higher peak pressures and faster apparent heat release rates (AHRR). LPG operation achieved higher brake thermal efficiencies and lower equivalent CO 2 emissions compared to CNG operation at the tested engine loads and compression ratios. LPG demonstrated significantly higher EGR tolerance limits compared to CNG, with a maximum of 28% EGR rate, compared to 23% for CNG. This improved EGR dilution tolerance was responsible for a 90% reduction in NOx emissions for LPG compared to a maximum of 70% with CNG. EGR dilution also exhibited more effective knock mitigation potential with LPG, suppressing knock intensity values by up to 98% and transitioning the engine operation towards normal combustion from heavy knocking conditions. As a result, the CIM was found to decrease burn durations and improve the quality of combustion by controlling the desired fraction of end-gas auto-ignition.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1983

Examination, evaluation and repair of laminated wood blades after service on the Mod-OA wind turbine

Laminated wood blades were designed, fabricated, and installed on a 200-KW wind turbine (Mod-OA). The machine uses a two-blade rotor with a diameter of 38.1 m (125 ft). Each blade weights less than 1361 kg (3000 lb). After operating in the field, two blade sets were returned for inspection. One set had been in Hawaii for 17 months (7844 hr of operation) and the other had been at Block Island, Rhode Island, for 26 months (22 months operating - 7564 hr). The Hawaii set was returned because of one of the studs that holds the blade to the hub had failed. This was found to be caused by a combination of improper installation and inadequate corrosion protection. No other problems were found. The broken stud (along with four others that were badly corroded) was replaced and the blades are now in storage. The Block Island set of blades was returned at the completion of the test program, but one blade was found to have developed a crack in the leading edge along the entire span. This crack was found to be the result of a manufacturing process problem but was not structurally critical. When a load-deflection test was conducted on the cracked blade, the response was identical to that measured before installation. In general, the laminate quality of both blade sets was excellent. No significant internal delamination or structural defects were found in any blade. The stud bonding process requires close tolerance control and adequate corrosion protection, but studs can be removed and replaced without major problems. Moisture content stabilization does not appear to be a problem, and laminated wood blades are satisfactory for long-term operation on Mod-OA wind turbines.

Faddoul, J. R.↗
NASA NTRS2019

Loftid Aeroshell Engineering Development Unit Structural Testing

NASA’s Hypersonic Inflatable Aerodynamic Decelerator (HIAD) technology was selected for a Technology Demonstration Mission under the Space Technology Mission Directorate in 2017. HIAD is an enabling technology that can facilitate atmospheric entry of heavy payloads to planets such as Earth and Mars using a deployable aeroshell. The deployable nature of the HIAD technology allows it to avoid the size constraints imposed on current rigid aeroshell entry systems. This enables use of larger aeroshells resulting in increased entry system performance (e.g. higher pay-load mass and/or volume, higher landing altitude at Mars). The Low Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) is currently scheduled for late-2021. LOFTID will be launched out of Vandenberg Air Force Base as a secondary payload on an Atlas V rocket. The flight test features a 6m diameter, 70-deg sphere-cone aeroshell and will provide invaluable high-energy orbital re-entry flight data. This data will be essential in supporting the HIAD team to mature the technology to diameters of 10m and greater. Aeroshells of this scale are applicable to potential near-term commercial applications and future NASA missions. Currently the LOFTID project has completed fabrication of the engineering design unit (EDU) inflatable structure (IS) and the flexible thermal protection system (F-TPS). These two components along with the rigid nose and center body comprise the HIAD aeroshell system. This EDU aeroshell is the precursor to the LOFTID aeroshell that will be used for flight. The EDU was built to verify the design given the subtle differences between the LOFTID aeroshell and past aeroshell designs that have been fabricated under the NASA HIAD project. To characterize the structural performance of the LOFTID aeroshell design, three structural tests will be performed. The first test to be conducted is static load testing, which will induce a uniform load across the forward surface of the aeroshell to simulate the expected pressure forces during atmospheric entry. The IS integrated with the rigid center body will first be tested alone to provide data for analytical model correlation, and then the F-TPS will be integrated for a second series of static load testing of the full aeroshell system. Instrumentation will be employed during the test series to measure component loads during testing, and a laser scanner will be used to generate a 3D map of the aeroshell surface to verify that the shape of the structure is acceptable at the simulated flight loads. After static load testing, pack and deployment testing will be conducted multiple times on the integrated system to demonstrate the aeroshell’s ability to fit within the required packed volume for the LOFTID mission without experiencing significant damage. Finally, the aeroshell will undergo modal testing to characterize its structural response. This presentation will discuss the setup and execution of each of the three tests that the EDU aeroshell will undergo. In addition, initial results of the testing will be presented outlining key findings as LOFTID moves for-ward with fabrication of the flight aeroshell.

Swanson, G. T.↗
NASA NTRS1982

Accelerated fatigue durability of a high performance composite

The fatigue behavior of multidirectional graphite-epoxy laminates was analyzed theoretically and experimentally in an effort to establish an accelerated testing methodology. Analysis of the failure mechanism in fatigue of the laminates led to the determination of the failure mode governing fracture. The nonlinear, cyclic-dependent shear modulus was used to calculate the changing stress field in the laminate during the fatigue loading. Fatigue tests were performed at three different temperatures: 25 C, 74 C, and 114 C. The prediction of the S-N curves was made based on the artificial static strength artificial static strength at a reference temperature and the fatigue functions associated with them. The prediction of an S-N curve at other temperatures was performed using shifting factors determined for the specific failure mode. For multidirectional laminates, different S-N curves at different temperatures could be predicted using these shifting factors. Different S-N curves at different temperatures occur only when the fatigue failure mode is matrix dominated. It was found that whenever the fatigue failure mode is fiber dominated, temperature, over the range investigated, had no influence on the fatigue life. These results permit the prediction of long-time, low temperature fatigue behavior from data obtained in short time, high temperature testing, for laminates governed by a matrix failure mode.

Rotem, A.↗
NASA NTRS1985

An examination of the relations between rotor vibratory loads and airframe vibrations

Harmonic rotor hub loads and airframe interactions in steady flight are reviewed, with regard to the objective of achieving lower airframe vibration by modifying blade root loads. Flight test and wind tunnel data are reviewed, along with sample fuselage response data. Trends which could provide a generalized approach to the above objective are found to be very limited. Recent analytical and corresponding experimental blade tuning modifications are reviewed and compared. Rotor vibratory load modification and substantial vibration changes were achieved over a wide range of rotor operating conditions.

Niebanck, C. F.↗
NASA NTRS1973

Fatigue-test acceleration with flight-by-flight loading and heating to simulate supersonic-transport operation

Possibilities for reducing fatigue-test time for supersonic-transport materials and structures were studied in tests with simulated flight-by-flight loading. In order to determine whether short-time tests were feasible, the results of accelerated tests (2 sec per flight) were compared with the results of real-time tests (96 min per flight). The effects of design mean stress, the stress range for ground-air-ground cycles, simulated thermal stress, the number of stress cycles in each flight, and salt corrosion were studied. The flight-by-flight stress sequences were applied to notched sheet specimens of Ti-8Al-1Mo-1V and Ti-6Al-4V titanium alloys. A linear cumulative-damage analysis accounted for large changes in stress range of the simulated flights but did not account for the differences between real-time and accelerated tests. The fatigue lives from accelerated tests were generally within a factor of two of the lives from real-time tests; thus, within the scope of the investigation, accelerated testing seems feasible.

Imig, L. A.↗
NASA NTRS1946

Free-spinning-tunnel Tests of a 1/26th Scale Model of the Douglas XTB2D-1 Airplane

A spin-tunnel investigation of a 1/26 scale model of the Douglas XTB2D-1 airplane has been conducted in the Langley 20-foot free-spinning tunnel. The effects of control settings and movements upon the erect- and inverted-spin and recovery characteristics of the model were determined for various loading conditions. Tests were also performed to determine the effects of various tail modifications. The investigation included emergency spin-recovery parachute tests as well as crew-escape and rudder- and elevator-force tests. All tests were performed at an equivalent spin altitute of 20,000 feet. The recovery characteristics of the model in the original design were found to be unsatisfactory. Installation of a large ventral fin, installation of tip fins on the horizontal tail, or installation of a small ventral fin in combination with antispan fillets and a spanwise extension of the horizontal-tail surfaces satisfactorily improved the recovery characteristics of the model.

Stone, Ralph W↗
NASA NTRS1985

Performance and loads data from a hover test of a full-scale XV-15 rotor

A hover test of a full-scale XV-15 rotor was conducted at the Outdoor Aerodynamic Research Facility at Ames Research Center. The primary objective of the test was to obtain accurate measurements of the hover performance of the original, metal-blade XV-15 rotor system. Data were acquired for rotor tip Mach numbers ranging from 0.60 to 0.73. This report presents data on rotor performance, rotor wake downwash velocities, and rotor loads.

Felker, F. F.↗
NASA NTRS2016

Assessment of the Uniqueness of Wind Tunnel Strain-Gage Balance Load Predictions

A new test was developed to assess the uniqueness of wind tunnel strain-gage balance load predictions that are obtained from regression models of calibration data. The test helps balance users to gain confidence in load predictions of non-traditional balance designs. It also makes it possible to better evaluate load predictions of traditional balances that are not used as originally intended. The test works for both the Iterative and Non-Iterative Methods that are used in the aerospace testing community for the prediction of balance loads. It is based on the hypothesis that the total number of independently applied balance load components must always match the total number of independently measured bridge outputs or bridge output combinations. This hypothesis is supported by a control volume analysis of the inputs and outputs of a strain-gage balance. It is concluded from the control volume analysis that the loads and bridge outputs of a balance calibration data set must separately be tested for linear independence because it cannot always be guaranteed that a linearly independent load component set will result in linearly independent bridge output measurements. Simple linear math models for the loads and bridge outputs in combination with the variance inflation factor are used to test for linear independence. A highly unique and reversible mapping between the applied load component set and the measured bridge output set is guaranteed to exist if the maximum variance inflation factor of both sets is less than the literature recommended threshold of five. Data from the calibration of a six{component force balance is used to illustrate the application of the new test to real-world data.

strain-gage balance↗
DOE OSTI2015

Design of a Compact Fatigue Tester for Testing Irradiated Materials

A compact fatigue testing machine that can be easily inserted into a hot cell for characterization of irradiated materials is beneficial to help determine relative fatigue performance differences between new and irradiated material. Hot cell use has been carefully considered by limiting the size and weight of the machine, simplifying sample loading and test setup for operation via master-slave manipulator, and utilizing an efficient design to minimize maintenance. Funded from a US-Japan collaborative effort, the machine has been specifically designed to help characterize titanium material specimens. These specimens are flat cantilevered beams for initial studies, possibly utilizing samples irradiated at other sources of beam. The option to test spherically shaped samples cut from the T2K vacuum window is also available. The machine is able to test a sample to $10^7$ cycles in under a week, with options to count cycles and sense material failure. The design of this machine will be presented along with current status.

Hartsell, Brian↗
DOE OSTI2023

Transient Modelling of HTGR Thermal Load Follow in Modelica

The ability of nuclear power plants to load follow electrical power demand is particularly important as we move to higher variable renewable (VRE) energy production on low carbon energy grids. High temperature gas reactors (HTGRs) are capable of load following by adjusting thermal output, but their high temperatures and thermal inertia significantly impact the power transients they are able to follow. To aid investigation into new integrated energy systems with advanced reactors, it is necessary to have an open-source transient model of a full HTGR primary and secondary. This paper introduces two new open-source models for a HTGR and corresponding balance of plant (BOP) written for the HYBRID library developed at Idaho National Laboratory. A transient thermal load follow test case was taken by the work from Brits et al. to benchmark our open-source model against transient operation results from other proprietary codes that exist. The control scheme for the two new models in combination is discussed and a comparison of the response in transient load follow between the two codes performed.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1976

An evaluation of dry film lubricants and substrate materials for use on SSME gimbal bearings

Failure of the spherical bearing shaft of the Space Shuttle Main Engine (SSME) gimbal bearing assembly was encountered during Design Verification Specification testing of the full scale engine. Investigation revealed that the failure was caused by a deficiency in the lubrication system. Based upon the materials and gimbal operating conditions, a lubricant of MoS2 and graphite with a ceramic binder was the best lubricant candidate for this particular application; however, the decision to implement the change was not made without verification testing. Scaled down simulation testing was performed. Four different substrate materials and eight different dry film lubricants were subjected to tests under simulated SSME environmental and stress load conditions. The test specimens were evaluated for friction and operating life. Each test specimen was subjected to cyclic operation under load until failure. The force required to move the bearing surfaces relative to each other was monitored throughout the test, thus providing analytical data for derivation of the coefficient of friction. Results indicate that the MoS2/graphite lubricant with ceramic binder proved to be superior from the standpoint of endurance and also from the standpoint of friction reducing capabilities when applied to the titanium substrate material used on SSME. Endurance of this lubricant was approximately 16 times that of the lubricant which was being used when the SSME gimbal failed.

Harp, J. A.↗
DOE OSTI2022

FY2021 Improvements to the New CTH Code Verification & Validation Test Suite

Over the past few years, the CTH multiphysics hydrocode has overhauled its software quality and testing processes, implementing current best practices in software quality and building a robust V&V test suite comprised of traditional hydrocode verification problems, including ASC Tri-Lab Test Suite and Enhanced Tri-Lab Test Suite problems, as well as validation problems for some of CTH’s most frequently used equations of state, materials models, and other key capabilities. Substantial progress towards building this new test suite was made in FY19 and FY20. In FY21, the test suite has been expanded to include verification and validation tests of the Steinberg-Guinan-Lund (ST) viscoplastic model and the Johnson Cook (JFRAC) fracture model. Additionally, two new verification tests were added, covering hydrodynamics and high explosive (HE) modeling capabilities: the Kidder Gaussian density problem and the Escape of HE Products (EHEP) problem from the Tri-Lab Test Suite. This report discusses each of these test problems in detail. Verification test results are compared to analytic solutions. Validation test results are compared to experimental data. Wherever possible, convergence or mesh refinement studies are included. Additionally, while implementing the Kidder verification problem, a bug was identified that affects the use of tables to initialize pressure or density in 1D or 2D calculations. A brief discussion of the bug and its fix is included. CTH demonstrates good performance overall on the new test suite problems. Simulation results showed good agreement with analytic solutions for the Kidder problem, with convergence rates ranging between 1.8 and sub-linear, and relatively good agreement for the EHEP problem, though convergence rates for pressure and density were nearly 0. The ST and JFRAC strain rate loading verification tests show good agreement with analytic solutions. Likewise, CTH simulation results show good agreement with experimental validation data, including Taylor rod impact testing, for the materials tested. Future V&V work will focus on adding 2D and 3D versions of existing verification tests as well as adding validation tests of other frequently used capabilities such as other fracture models.

42 ENGINEERING↗
DOE OSTI2021

Low Temperature Water-Gas Shift: Enhancing Stability through Optimizing Rb Loading on Pt/ZrO 2

Recent studies have shown that appropriate levels of alkali promotion can significantly improve the rate of low-temperature water gas shift (LT-WGS) on a range of catalysts. At sufficient loadings, the alkali metal can weaken the formate C–H bond and promote formate dehydrogenation, which is the proposed rate determining step in the formate associative mechanism. In a continuation of these studies, the effect of Rb promotion on Pt/ZrO 2 is examined herein. Pt/ZrO 2 catalysts were prepared with several different Rb loadings and characterized using temperature programmed reduction mass spectrometry (TPR-MS), temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), an X-ray absorption near edge spectroscopy (XANES) difference procedure, extended X-ray absorption fine structure spectroscopy (EXAFS) fitting, TPR-EXAFS/XANES, and reactor testing. At loadings of 2.79% Rb or higher, a significant shift was seen in the formate ν(CH) band. The results showed that a Rb loading of 4.65%, significantly improves the rate of formate decomposition in the presence of steam via weakening the formate C–H bond. However, excessive rubidium loading led to the increase in stability of a second intermediate, carbonate and inhibited hydrogen transfer reactions on Pt through surface blocking and accelerated agglomeration during catalyst activation. Optimal catalytic performance was achieved with loadings in the range of 0.55–0.93% Rb, where the catalyst maintained high activity and exhibited higher stability in comparison with the unpromoted catalyst.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1987

Performance and loads data from a hover test of a 0.658-scale V-22 rotor and wing

A hover test of a 0.658-scale model of a V-22 rotor and wing was conducted at the Outdoor Aerodynamic Research Facility at Ames Research Center. The primary objectives of the test were to obtain accurate measurements of the hover performance of the rotor system, and to measure the aerodynamic interactions between the rotor and wing. Data were acquired for rotor tip Mach numbers ranging from 0.1 to 0.73. This report presents data on rotor performance, rotor-wake downwash velocities, rotor system loads, wing forces and moments, and wing surface pressures.

Felker, Fort F.↗
NASA NTRS1984

Transient vibration test criteria for spacecraft hardware

Transient vibration test criteria, developed for spacecraft hardware, provide a test rationale to verify the capability of the hardware to withstand the low and mid frequency transient vibration environments induced by launch vehicle events. A test method, consisting of a series of discrete frequency, limited cycle, modulated sine wave pulses, was developed to avoid the slow swept sine drawbacks, yet provide a repeatable test that would excite all frequencies. The shape of the waveform is that of the classic response of the mass of a one degree of freedom system when it is base-excited by an exponentially decayed sine wave transient. Criteria were developed to define pulse amplitudes, shapes, and center frequencies from spacecraft loads analyses. Test tolerance criteria were also developed and specified. The transient vibration test criteria were implemented on spacecraft flight hardware and provided a more realistic test simulation (i.e., less conservative) for qualification of spacecraft hardware without risk of undertest.

Kern, D. L.↗
NASA NTRS1992

Laboratory evaluation of footings for lunar telescopes

Presented here are the results of laboratory experiments with diffferent footing shapes for lunar telescopes. These experiments used a variety of soils including some to simulate regolith response. Based on what is known of regolith and regolith-structure interaction, a shallow-multiple-contact points footing foundation can be adequately designed to support lunar telescopes. Plane-strain load-displacement tests were conducted with different footings and different lunar simulants in a deep transparent plexiglass container. The model footings considered include the rectangular, hemispherical, and spudcan designs. Simulants used to reproduce the mechanical properties of the lunar regolith were fly ash, crushed basalt with and without glass, and a processed lunar simulant. Load-displacement curves were obtained for the different footings in Ottawa sand and in the crushed basalt with glass. The spudcan footing was found to be self-digging and yet stiff, thus providing excellent lateral stability in a large variety of soils.

Chua, Koon M.↗