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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1964

Blast Effects of Twin Variable-Cant Rocket Nozzles on Visibility During Landing on a Particle-Covered Surface

A limited investigation has been conducted to determine the jet-blast effect of twin variable-cant supersonic nozzles. These tests were made to examine the result of using canted main rocket engines to sweep the blast debris outward from the proposed landing area of a rocket-powered vehicle making a vertical approach to a touchdown. Cant angles from 0 degrees to 75 degrees, at intervals of 15 degrees, were tested at low ambient pressure and at atmospheric ambient pressure. Nozzle chamber pressures used were 400 psi and 2000 psi.

EXPERIMENTS↗
NASA NTRS2007

Infrared and X-Ray Evidence for Circumstellar Grain Destruction by the Blast Wave of Supernova 1987A

Multiwavelength observations of supernova remnant (SNR) 1987A show that its morphology and luminosity are rapidly changing at X-ray, optical, infrared, and radio wavelengths as the blast wave from the explosion expands into the circumstellar equatorial ring, produced by mass loss from the progenitor star. The observed infrared (IR) radiation arises from the interaction of dust grains that formed in mass outflow with the soft X-ray emitting plasma component of the shocked gas. Spitzer IRS spectra at 5 - 30 microns taken on day 6190 since the explosion show that the emission arises from approx. 1.1 x 10(exp -6) solar mass of silicate grains radiating at a temperature of approx. 180+/-(15-20) K. Subsequent observations on day 7137 show that the IR flux had increased by a factor of 2 while maintaining an almost identical spectral shape. The observed IR-to-X-ray flux ratio (IRX) is consistent with that of a dusty plasma with standard LMC dust abundances. This flux ratio has decreased by a factor of approx. 2 between days 6190 and 7137, providing the first direct observation of the ongoing destruction of dust in an expanding SN blast wave on dynamic time scales. Detailed models consistent with the observed dust temperature, the ionization fluence of the soft X-ray emission component, and the evolution of IRX suggest that the radiating si1icate grains are immersed in a 3.5 x 10(exp 6) K plasma with a density of (0.3 - 1) x 10(exp 4)/cu cm, and have a size distribution that is confined to a narrow range of radii between 0.02 and 0.2 microns. Smaller grains may have been evaporated by the initial UV flash from the supernova.

Dwek, Eliahu↗
NASA NTRS2003

Lightweight Energy Absorbers for Blast Containers

Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

Balles, Donald L.↗
NASA NTRS2007

Predicting the Blast of Lunar Soil Under a Rocket's Exhaust Jet

The blast of lunar soil represents a problem for the future missions planned for the moon. When the lander approached the ground during the Apollo missions, huge showers of dust particles were sent in all directions at extremely high velocities - including upwards towards the landing spacecraft. This represents a clear danger to the lander because the loss of visibility and the damage that can be produced to the vehicle itself. If there had been equipment on the ground, these showers of particles would have created a sand blasting effect over the equipment, possibly damaging optics and contaminating the equipment and depending on the size and velocity of the particles maybe even more extensive damage as the particles penetrated the outer surface of the equipment. Since the there is no air on the moon to slow down the particles, they can travel large distances at high speeds, in fact in some instances they can reach near escape velocity and go into an orbit around the moon and come all the way back to almost the same point where they were at the beginning; meaning that some of the lunar dust that came up during landing will shower back over the site. Once on the surface, the extremely fine dust had a habit of getting itself everywhere. During the Apollo missions it not only covered the astronauts' suits, but managed to work its way inside, damaging airtight joints and scratching up glass visors. The dust found its way inside the spacecraft, contaminating the floor and electronic systems inside, clogging air filters in the process. This is due to the fact that the lunar soil is extremely cohesive. The Lunar soil causes all of the same problems as sand does on Earth but unlike sand particles on Earth, which have smooth spherical shapes, the dust on the Moon is more like small particles of glass with sharper edges since there is no erosion on the lunar surface. During the Apollo missions the dust problem did not cause a big problem due to the fact of the length of duration of the missions. But as NASA plans to have long term missions to the moon the dust problem becomes an issue, due to multiple landings and the equipment that will be accumulated on the site. In order to mitigate these problems it is needed first to understand the physics of the problem in order to find the most suitable solution to protect equipment and vehicles during the next lunar missions..

Diaz, Carlos J. Sanchez↗
NASA NTRS2013

An Early and Comprehensive Millimetre and Centimetre Wave and X-Ray Study of SN 2011dh: a Non-Equipartition Blast Wave Expanding into a Massive Stellar Wind

Only a handful of supernovae (SNe) have been studied in multiwavelengths from the radio to X-rays, starting a few days after the explosion. The early detection and classification of the nearby Type IIb SN 2011dh/PTF 11eon in M51 provides a unique opportunity to conduct such observations. We present detailed data obtained at one of the youngest phase ever of a core-collapse SN (days 3-12 after the explosion) in the radio, millimetre and X-rays; when combined with optical data, this allows us to explore the early evolution of the SN blast wave and its surroundings. Our analysis shows that the expanding SN shock wave does not exhibit equipartition (epsilon(sub e)/epsilon(sub B) approx. 1000), and is expanding into circumstellar material that is consistent with a density profile falling like R(exp −2). Within modelling uncertainties we find an average velocity of the fast parts of the ejecta of 15 000 +/- 1800 km/s, contrary to previous analysis. This velocity places SN 2011dh in an intermediate blast wave regime between the previously defined compact and extended SN Type IIb subtypes. Our results highlight the importance of early (approx.1 d) high-frequency observations of future events. Moreover, we show the importance of combined radio/X-ray observations for determining the microphysics ratio epsilon(sub e)/epsilon(sub B).

gamma rays↗
DOE OSTI2016

Optimising Blends of Blast Furnace Slag for the Immobilisation of Nuclear Waste - 16245

The legacy of nuclear waste at the Sellafield site in the UK is an ongoing issue, and the current preferred route for the disposal of low and intermediate level waste is encapsulation in a cementitious matrix, formulated by blending Portland cement with blast furnace slag (BFS). Due to demands and economic challenges faced by the cement and steel industries, the supply of BFS to the UK nuclear industry has been inconsistent. These changes have caused the industry to move from a unique BFS powder supply with a certain specification to a combination of standard commercially available cementitious powders. The material currently used at the Sellafield site is a blend of ground granulated blast furnace slag (GGBS) and a coarser fraction of the same composition called Calumite, combined with Portland cement. This work involves future-proofing the supply of BFS for the UK nuclear industry by optimising the blend of the two fractions of BFS in order to replicate the unique specification required by Sellafield Ltd. The main emphasis is on the particle size distribution (PSD) and how this impacts the properties of the final wasteform. The study investigates the performance properties of the blended grouts such as workability, particle packing and heat evolution. Results show that the PSD of the cement powders affect both the physical and chemical properties of the cementitious matrix produced. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

The Blast Parameters Spanning the Fireball from Large Hemispherical Detonations of C-4

In this study, large (~45.4 kg) hemispheres of C-4, detonated on the ground, were instrumented to measure blast parameters at scaled distances between 0.53 to 1.78 m kg -1/3 . The results from free-field and reflected pressure gauge measurements made inside and just outside the maximum extent of the fireball are presented. They show that the predictions from a particular table for scaled TNT charges are broadly consistent with the time-of-arrival, initial peak pressure, positive duration and positive impulse measurements. However, this agreement is poorer through the location of the primary and secondary (delayed) fireball (0.71–1.48 m kg -1/3 ), but better closer in and further away. Additionally, for individual detonations with closely located gauges, significant variations between peak pressures and times-of-arrival are measured. Lastly, this suggests a strong effect from the interface instabilities present in the near-field.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2018

Numerical Investigation of Novel Oxygen Blast Furnace Ironmaking Processes

Oxygen blast furnace (OBF) ironmaking process has the potential to realize “zero carbon footprint” production, but suffers from the “thermal shortage” problem. This paper presents three novel OBF processes, featured by belly injection of reformed coke oven gas, burden hot-charge operation, and their combination, respectively. These processes were studied by a multifluid process model. The applicability of the model was confirmed by comparing the numerical results against the measured key performance indicators of an experimental OBF operated with or without injection of reformed coke oven gas. Then, these different OBF processes together with a pure OBF were numerically examined in aspects of in-furnace states and global performance, assuming that the burden quality can be maintained during the hot-charge operation. The numerical results show that under the present conditions, belly injection and hot charge, as auxiliary measures, are useful for reducing the fuel rate and increasing the productivity for OBFs but in different manners. Hot charge should be more suitable for OBFs of different sizes because it improves the thermochemical states throughout the dry zone rather than within a narrow region in the case of belly injection. The simultaneous application of belly injection and hot charge leads to the best process performance, at the same time, lowering down hot-charge temperature to achieve the same carbon consumption and hot metal temperature as that achieved when applying the hot charge alone. This feature will be practically beneficial in the application of hot-charge operation. In addition, a systematic study of hot-charge temperature reveals that optimal hot-charge temperatures can be identified according to the utilization efficiency of the sensible heat of hot burden.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Effect of Hydrogen Addition on Softening and Melting Reduction Behaviors of Ferrous Burden in Gas-Injection Blast Furnace

The softening and melting reduction behaviors of ferrous burden in a gas-injection blast furnace (BF) have been investigated experimentally with the assistance of H{sub 2}. The results indicate that the initial softening temperature of the burden in the BF is lower than that in the traditional BF, while the opposite trend is observed for its melting and dripping temperatures, thus widening the softening range and narrowing the melting zone. As a result, the permeability of the stock column is apparently improved, owing to the decreased amount of the produced melt. After H{sub 2} gas is added, the thickness of the iron shell of the burden pellet increases, and the quantity of its liquid wüstite core decreases due to the higher reduction degree. The reduction rate of iron oxides is much faster than the carburization rate with the H{sub 2} addition, and the dripping behavior of the ferrous burden is determined by the carburization with a high reduction potential. After taking into account the effects of H{sub 2} addition on the iron oxide reduction rate, melt quantity, burden microstructure, and energy consumed by the gas-injection BF, it has been concluded that the optimal H{sub 2} content lies in the range between 10 and 15 pct.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Transient Interaction Between Reduction and Slagging Reactions of Wustite in Simulated Cohesive Zone of Blast Furnace

The blast furnace cohesive zone plays an important role in the gas flow distribution and heat-transfer efficiency. Previous work mainly employed temperature-based indices to evaluate and predict the shape and thickness of the cohesive zone, whereas the internal reactions and related effects on the softening and melting properties of a complex burden are ignored. In this study, an innovative index, namely, shrinkage rate (SR), is first proposed to directly estimate the shrinkage behavior of wustite (FeO)-packed bed inside a simulated cohesive zone. The index is applied as the temperature increases to elucidate the transient interaction between reduction and slagging reactions. Results show that the thermally induced slagging reaction causes the packed bed to shrink at lower temperature, and the SR doubles when compounds with low melting temperature are generated by adding a reasonable concentration of CaO or SiO{sub 2}. The reduction reaction becomes the driving force during the shrinkage of the packed bed between 1173 K and 1273 K when CO is introduced in the mixture gas. Then, the dominating factors for further shrinkage include slagging, reduction, or both factors. These factors vary with respect to the added compounds or temperature.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Modelling of Blast Furnace with Respective Chemical Reactions in Coke and Ore Burden Layers

The ironmaking blast furnace (BF) is an efficient chemical reactor for producing liquid iron from solid iron ore, where the solids of coke and iron ore are charged in alternative layers and different chemical reactions occur in the two solid layers as they descend. Such respective reacting burden layers have not been considered explicitly in the previous BF models. In this article, a mathematical model based on multi-fluid theory is developed for describing the multiphase reacting flows considering the respective reacting burden layers. Then, this model is applied to a BF, covering the area from the burden surface at the furnace top to the liquid surface above the hearth, to describe the inner states of a BF in terms of the multiphase flows, temperature distribution and reduction process. The results show that some key important features in the layered burden with respective chemical reactions are captured, including fluctuating iso-lines in terms of gas flow and thermochemical behaviours; particularly the latter cannot be well captured in the previous BF models. The temperature difference between gas–solid phases is found to be larger near the raceway, at the cohesive zone and at the furnace top, and the thermal reserved zone can be identified near the shaft. Three chemical reserve zones of hematite, magnetite and wustite can also be observed near the stockline, in the shaft near the wall and near centre, respectively. Inside each reserve zone, the corresponding ferrous oxides stay constantly high in alternative layers; the overall performance indicators including gas utilization efficiency and reduction degree also stay stable in an alternative-layered structure. This model provides a cost-effective tool to investigate the BF in-furnace process and optimize BF operation.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Increased Use of Natural Gas in Blast Furnace Ironmaking: Mass and Energy Balance Calculations

In blast furnace ironmaking, coke can be partially replaced by injected natural gas. Tuyère injection of cold natural gas is commonly practiced in North America. In this work, limits to the tuyère injection rate have been quantified with mass and energy balances. The fundamental origin of the limits is the endothermicity of methane injection. In principle, shaft injection of preheated and partially combusted methane would obviate the endothermic effect. However, the thermal and chemical energy parameter indicates that the energy requirement in the lower part of the furnace—to melt hot metal and slag—might not be met in the case of shaft injection. Tuyère injection of preheated methane might be a feasible alternative. Calculated combustion kinetics support the feasibility of partial combustion of preheated methane (with sub-stoichiometric oxygen) before injection.

36 MATERIALS SCIENCE↗
DOE OSTI2019

High-Temperature Interactions Between Vanadium-Titanium Magnetite Carbon Composite Hot Briquettes and Pellets Under Simulated Blast Furnace Conditions

The high-temperature interactions between vanadium-titanium magnetite carbon composite hot briquettes (VTM-CCBs) and pellets were systematically investigated under simulated blast furnace conditions with respect to the reduction behavior, softening–melting–dripping characteristics, gas permeability, and Ti(C, N) precipitation mechanisms. The results showed that VTM-CCB charging can promote the reduction of the pellet in the packed bed and decrease the compressive strength of the pellet after reduction. The compressive strength of the VTM-CCB after reduction decreased with increasing temperature when the FC/O ratio (the ratio of the fixed carbon mol(C) in coal to the reducible oxygen mol(O) in iron oxides) was higher than 1.0. With an FC/O ratio lower than 1.0, the compressive strength of the VTM-CCB initially decreased and then increased. The FC/O ratio has a significant influence on the softening–melting interaction mechanism between the VTM-CCB and the pellet. With an FC/O ratio of 0.8, the bonding layer at the interface between the pellet and the VTM-CCB (consisting of molten fayalitic slag) can promote the softening process, thereby decreasing the softening start and end temperatures. By increasing the FC/O ratio to 1.4, a dense metallic iron shell with relatively high strength formed at the interface and restricted the collapse of the packed bed, thereby increasing the softening start and end temperatures and ensuring the transport of the reduction gas through the packed bed. The melting point of the primary slag phase increased with increasing FC/O ratio due to a decrease in the FeO content, which resulted in an increase in the melting start temperature from 1273 °C to 1294 °C (1546 K to 1567 K). The gas permeability in the cohesive zone increased with an increasing FC/O ratio of the VTM-CCB due to a combination of the skeletal role performed by the residual VTM-CCB and the decrease in the liquid slag proportion. In addition, as the FC/O ratio increased to 1.4, unconsumed carbon promoted the precipitation of Ti(C, N) at the slag–carbon and slag–metal interfaces, which resulted in a substantial increase in the dripping temperature and deterioration of the dripping behavior of the packed bed. Therefore, to suppress the precipitation of Ti(C, N) and improve the dripping behavior of the packed bed, the FC/O ratio of the charged VTM-CCB should be controlled within an appropriate range.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Reduction Mechanism of Iron Oxide Briquettes by Carbonaceous Materials Extracted from Blast Furnace Dust

The reducibility of carbonaceous powder extracted from blast furnace dust was investigated. In this study, pickling treatment was used for BF bag dust and BF gravitational dust to extract the carbonaceous material. The structural characteristics of carbonaceous material were studied by X-ray diffraction, scanning electron microscope, and energy-dispersive spectrometer. The reduction of ferric oxide and carbon gasification experiments were researched by thermogravimetry. The results show that the pickled raw coal gives the highest reducibility, which is followed by BF bag dust and BF gravitational dust. The reason for this is that the higher disordered crystalline structure leads to stronger gasification reactivity, and further results in stronger reduction reactivity. Based on the randomized nucleation model, the kinetic analysis shows that the activation energies for the reduction reaction of BF gravitational dust, BF bag dust, and raw coal after pickling are 300.14, 180.43, and 124.62 kJ mol{sup −1}, respectively.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Model Study of Blast Furnace Operation with Central Coke Charging

Blast furnace (BF) remains the dominant ironmaking process worldwide. Central coke charging (CCC) operation is a promising technology for stabilizing BF operations, but it needs reliable and quantified process design and control. In this work, a multi-fluid BF model is further developed for quantitatively investigating flow-thermal-chemical phenomena of a BF under CCC operation. This model features the respective chemical reactions in the respective coke and ore layers, and a specific sub-model of layer profile for the burden structure for the CCC operation. The simulation results confirm that the gas flow patterns and cohesive zone’s shape and location under the CCC operation are quite different from the non-CCC operation. Under the CCC operation, the heat is overloaded at the furnace center while the reduction load is much heavier at the periphery regions; the profiles of top gas temperature and gas utilization show bell-shape and inverse-bell-shape patterns, respectively. More importantly, these differences are characterized quantitatively. In this given case, when the CCC opening radius at the throat is 0.35 m, the cohesive zone top opening radius is around 0.50 m, and the isotherms of CCC operation become much steeper (~ 80 deg) than those of non-CCC operation (~ 60 deg) near BF central regions. In addition, it is confirmed that carbon solution-loss reaction rate can be decreased significantly at BF central regions under CCC operation. The model helps to understand CCC operation and provides a cost-effective method for optimizing BF practice.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Use of CaO as an activator for producing a price-competitive non-cement structural binder using ground granulated blast furnace slag

The use of calcium oxide (CaO) demonstrates a superior potential for the activation of ground granulated blast furnace slag (GGBFS), and it produces a higher mechanical strength than calcium hydroxide [Ca(OH){sub 2}]. The mechanical strength differences between CaO- and Ca(OH){sub 2}-activated GGBFS binders are explored using isothermal calorimetry, powder X-ray diffraction, thermogravimetric and differential thermal analysis (TGA and DTA) as well as compressive strength testing. Calcium silicate hydrate (C–S–H), Ca(OH){sub 2} and a hydrotalcite-like phase are found as reaction products in all samples. The TGA and DTA results indicate that the use of CaO produces more C–S–H, although this is not likely to be the primary cause of higher strength development in the CaO-activated GGBFS. Rather, other factors such as porosity may govern the strength at a higher order of magnitude. Significant reduction of Ca(OH){sub 2} occurs only with the use of Ca(OH){sub 2}, followed by the formation of carbonate (CaCO{sub 3}), indicating carbonation. -- Highlights: •CaO showed a better potential for the activation of GGBFS than Ca(OH){sub 2}. •Strength test, XRD, TGA/DTA and isothermal calorimetry are used. •C-S-H, Ca(OH){sub 2}, and a hydrotalcite-like phase are found in all samples. •The use of Ca(OH){sub 2} causes some degree of carbonation.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Effect of blast furnace slag on self-healing of microcracks in cementitious materials

The physico-chemical process of self-healing in blast furnace slag cement paste was investigated in this paper. With a high slag content i.e., 66% in cement paste and saturated Ca(OH)₂ solution as activator, it was found that the reaction products formed in cracks are composed of C-S-H, ettringite, hydrogarnet and OH–hydrotalcite. The fraction of C-S-H in the reaction products is much larger than the other minerals. Large amount of ettringite formed in cracks indicates the leaching of SO₄⁻² ions from the bulk paste and consequently the recrystallization. Self-healing proceeds fast within 50 h and then slows down. According to thermodynamic modeling, when the newly formed reaction products are carbonated, the filling fraction of crack increases first and then decreases. Low soluble minerals such as silica gel, gibbsite and calcite are formed. Compared to Portland cement paste, the potential of self-healing in slag cement paste is higher when the percentage of slag is high. Highlights: • Self-healing reaction products in slag cement paste were characterized. • Self-healing reaction products formed in time were quantified with image analysis. • Self-healing in slag cement paste was simulated with a reactive transport model. • Effect of carbonation on self-healing was investigated by thermodynamic modeling. • Effect of slag on self-healing was discussed based on experiments and simulation.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Characterisation of magnesium potassium phosphate cements blended with fly ash and ground granulated blast furnace slag

Magnesium potassium phosphate cements (MKPCs), blended with 50 wt.% fly ash (FA) or ground granulated blast furnace slag (GBFS) to reduce heat evolution, water demand and cost, were assessed using compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy on {sup 25}Mg, {sup 27}Al, {sup 29}Si, {sup 31}P and {sup 39}K nuclei. We present the first definitive evidence that dissolution of the glassy aluminosilicate phases of both FA and GBFS occurred under the pH conditions of MKPC. In addition to the main binder phase, struvite-K, an amorphous orthophosphate phase was detected in FA/MKPC and GBFS/MKPC systems. It was postulated that an aluminium phosphate phase was formed, however, no significant Al–O–P interactions were identified. High-field NMR analysis of the GBFS/MKPC system indicated the potential formation of a potassium-aluminosilicate phase. This study demonstrates the need for further research on these binders, as both FA and GBFS are generally regarded as inert fillers within MKPC.

36 MATERIALS SCIENCE↗