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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Modular Plasma Microreactor for Intensified Hydrogen Peroxide Production

Sustainable and decentralized manufacturing of hydrogen peroxide (H 2 O 2 ) has been extensively sought to replace the energy- and waste-intensive anthraquinone process. We introduce a helical biphasic microreactor in a coaxial dielectric barrier discharge (DBD) configuration as a modular, adaptable, and scalable intensified unit for H 2 O 2 production. Geometric and operating parameters such as electrode length, applied voltage, and gas and liquid flow rates can be tuned to regulate the residence time, delivered power, and gas–liquid interfacial area. In turn, these affect the key output parameters, i.e., H 2 O 2 concentration, production rate, and energy yield. We found a direct correlation between the H 2 O 2 production rate and the product of the interfacial area and residence time in the plasma region. We investigated the H 2 O 2 formation pathways using DMSO as an ·OH radical scavenger and found that H 2 O 2 forms by the dissolution of gaseous H 2 O 2 at low interfacial areas and is enhanced probably due to the interfacial recombination of ·OH radicals at a large gas–liquid interfacial area. The reactor temperature can also be externally controlled to intensify the production rate and energy yield of H 2 O 2 . Concentrations of up to 33 mM can be attained with a small footprint reactor that features a maximum energy yield of 4 g kWh –1 . Here, the plasma microreactor could epitomize a powerful process intensification tool for sustainable and distributed chemical manufacturing.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1970

Laser-Doppler gas velometer

Three dimensional laser Doppler instrument measures both local mean and fluctuating gas velocity of air flow. Technique is used for measuring atmospheric wind velocity and turbulence. Under certain conditions liquid flows can be measured.

Huffaker, R. M.↗
NASA NTRS1970

Two-phase flow and heat transfer in porous beds under variable body forces, part 7

The design of an experiment to determine the behavior of two-phase vapor-liquid and gas-liquid flow through porous beds in low gravity environments is discussed. The selection of porous materials, liquids, and gases is described. The parameters necessary for the design and development of a flight experimental system are examined. The general specifications for system elements requiring additional development are identified.

Henry, H. R.↗
NASA NTRS2000

A Remote Sensing/Geographic Information Systems Approach in the Selection of Mars Sites of Biological Interest

The search for extinct or extant life on Mars is the search for past or present liquid water, respectively. There are numerous signs of past liquid water on Mars in the form of dry river valleys, paleolakes, and their associated flow and sediment patterns. While some of these features are recent (Amazonian, 1.8 billion years ago to present), there is no evidence that any are currently flowing. Liquid water on the surface would only be possible at those sites with sufficiently high temperatures and pressure. The key to the selection of sites on Mars to search for evidence of life is the search for the presence of water. An approach to this problem is the use of remotely sensed data incorporated in a geographic information system (GIS). A GIS is a computer-based system capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e., data identified according to their locations. In planetary studies these data are acquired from remote sensing (RS) platforms (orbiters). These data are co-registered layers and, through the use of GIS analysis functions, areas on these layers can be selected as a function of the information desired. Our work used existing data layers from the Viking and Mars Global Surveyor missions to determine where water could be possible in liquid form on the Martian surface, based on the phase diagram for water.

Lobitz, B. M.↗
NASA NTRS1991

Definition of two-phase flow behaviors for spacecraft design

Data for complete models of two-phase flow in microgravity are taken from in-flight experiments and applied to an adiabatic flow-regime analysis to study the feasibility of two-phase systems for spacecraft. The data are taken from five in-flight experiments by Hill et al. (1990) in which a two-phase pump circulates a freon mixture and vapor and liquid flow streams are measured. Adiabatic flow regimes are analyzed based on the experimental superficial velocities of liquid and vapor, and comparisons are made with the results of two-phase flow regimes at 1 g. A motion analyzer records the flow characteristics at a rate of 1000 frames/sec, and stratified flow regimes are reported at 1 g. The flow regimes observed under microgravitational conditions are primarily annular and include slug and bubbly-slug regimes. The present data are of interest to the design and analysis of two-phase thermal-management systems for use in space missions.

Reinarts, Thomas R.↗
DOE OSTI2021

Biocatalytic Yarn for Peroxide Decomposition with Controlled Liquid Transport

In this study, a robust biocatalytic yarn with controllable liquid transport properties is created by coating thin layers of chitosan containing catalase onto a cellulosic yarn. The resulting material integrates enzyme catalytic functionality with protective coating properties of chitosan and structural functionality of the textile. Mild immobilization conditions and good affinity between the two polysaccharides minimize enzyme inactivation during the preparation steps and prevent enzyme from leaching during peroxide decomposition testing and washing, providing a novel and versatile enzyme immobilization strategy. The catalytic efficiency of enzymes in a reaction containing solid, liquid, and gas phases is facilitated when dissolved enzyme substrate is transported by liquid flowing through the coated textile structure. The flow-through configuration decomposes at least two times more peroxide in a twenty-times smaller reaction zone volume compared to a stirred tank configuration. Liquid transport through the yarn and liquid spatial distribution within the yarn are investigated by in situ neutron radiography and neutron computed tomography, revealing a constrained wicking mechanism that benefits biocatalytic yarn performance. This new class of sustainable and flexible biocatalytic textile matrices has beneficial multifunctional properties, not previously described, that are applicable for numerous small- and large-scale applications including controlled flow reactors and reactive filtration.

36 MATERIALS SCIENCE↗
NASA NTRS1999

Manipulating Liquids With Acoustic Radiation Pressure Phased Arrays

High-intensity ultrasound waves can produce the effects of "Acoustic Radiation Pressure" (ARP) and "acoustic streaming." These effects can be used to propel liquid flows and to apply forces that can be used to move or manipulate floating objects or liquid surfaces. NASA's interest in ARP includes the remote-control agitation of liquids and the manipulation of bubbles and drops in liquid experiments and propellant systems. A high level of flexibility is attained by using a high-power acoustic phased array to generate, steer, and focus a beam of acoustic waves. This is called an Acoustic Radiation Pressure Phased Array, or ARPPA. In this approach, many acoustic transducer elements emit wavelets that converge into a single beam of sound waves. Electronically coordinating the timing, or "phase shift," of the acoustic waves makes it possible to form a beam with a predefined direction and focus. Therefore, a user can direct the ARP force at almost any desired point within a liquid volume. ARPPA lets experimenters manipulate objects anywhere in a test volume. This flexibility allow it to be used for multiple purposes, such as to agitate liquids, deploy and manipulate drops or bubbles, and even suppress sloshing in spacecraft propellant tanks.

Oeftering, Richard C.↗
DOE OSTI2023

Functional Janus structured liquids and aerogels

Janus structures have unique properties due to their distinct functionalities on opposing faces, but have yet to be realized with flowing liquids. We demonstrate such Janus liquids with a customizable distribution of nanoparticles (NPs) throughout their structures by joining two aqueous streams of NP dispersions in an apolar liquid. Using this anisotropic integration platform, different magnetic, conductive, or non-responsive NPs can be spatially confined to opposite sides of the original interface using magnetic graphene oxide (mGO)/GO, Ti 3 C 2 T x /GO, or GO suspensions. The resultant Janus liquids can be used as templates for versatile, responsive, and mechanically robust aerogels suitable for piezoresistive sensing, human motion monitoring, and electromagnetic interference (EMI) shielding with a tuned absorption mechanism. The EMI shields outperform their current counterparts in terms of wave absorption, i.e., SE T ≈ 51 dB, SE R ≈ 0.4 dB, and A = 0.91, due to their high porosity ranging from micro- to macro-scales along with non-interfering magnetic and conductive networks imparted by the Janus architecture.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

The Onset of Nucleate Boiling Prediction in a Mini Channel with the Eulerian Multiphase Flow

The prediction of boiling incipience is a critical issue for a reactor. Vapor lock causes operating instability and undesirable temperature rise, especially for small channels. This study uses the Eulerian multiphase flow boiling model to predict the onset of nucleate boiling in a millimeter scale rectangular channel. Two wall boiling models, namely the RPI (Rensselaer Polytechnic Institute) and the non-equilibrium sub cooled model are applied. Computational fluid dynamics is employed for this study to investigate the impact of operating conditions like liquid flow rate, operating pressure, heat flux, velocity profile, turbulence model, and inlet liquid temperature. Here, the effect of fundamental boiling parameters on the surface wall temperature and vapor volume fraction is also studied. The parameters under consideration are the bubble departure diameter, bubble departure frequency, nucleate site density, quenching time period, and interface heat transfer coefficients. A series of CFD calculations is conducted by varying the considered variables systematically in a wide range of flow conditions covering laminar, transition, and turbulent flows. The sub-component heat fluxes like the liquid convective, the vapor convective, the evaporative, and the quenching terms are monitored to infer the boiling dynamics in the transition region from the single-phase flow to the nucleate boiling zone. It is found that the CFD approach to detecting the boiling incipience point agrees reasonably with available experimental data. However, its limitations, like inaccuracy for lower flow rates and early transition to boiling flow, are also noticed due to the nature of the considered RPI model.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1982

The effect of small temperature gradients on flow in a continuous flow electrophoresis chamber

Continuous flow electrophoresis employs an electric field to separate biological cells suspended in a flowing liquid buffer solution. Good separations based on differences in electrophoretic mobility are obtained only when a unidirectional flow is maintained. The desired flow has a parabolic structure in the narrow dimension of the chamber and is uniform acros the width, except near the edges where the no-slip condition prevails. However, because of buoyancy, very small laterall or axial temperature gradients deform the flow significantly. The results of experiments conducted with a specially instrumented chamber show the origin and structure of the buoyancy-driven perturbations. It is found that very small temperature gradients can disturb the flow significantly, as was predicted by earlier theoretical work.

Rhodes, P. H.↗
NASA NTRS1992

Two-phase flow characterization for fluid components and variable gravity conditions

This paper describes a program initiated by the NASA Johnson Space Center to investigate vapor-liquid flow regimes and pressure drops in pipe components and variable gravity conditions. This program supports the Space Station Freedom External Active Thermal Control System design and future space missions, including the Space Exploration Initiative activities. The objectives for this program include studying two-phase flow behavior in fluid components (smooth pipes, bellows lines, quick-disconnect fittings), expanding the two-phase database for zero-g conditions, developing a database for low-g conditions (for example, Moon-g, Mars-g), and validating models for two-phase flow analyses. Zero-g and low-g data will be gathered using a Freon-12 flow loop during four test series on the KC-135 aircraft beginning in August 1991.

Dzenitis, John M.↗
NASA NTRS2016

A Study of Heat Transfer and Flow Characteristics of Rising Taylor Bubbles

Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the systems heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles.An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kgm2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocityon the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign.Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field. Results were compared and shown to agree with numerical simulations of colleagues from EPFL, Switzerland.In addition, a preliminary study was completed on the effect of a Taylor bubble passing through nucleate flow boiling, showing that the thinning thermal boundary layer within the film suppressed nucleation, thereby decreasing the heat transfer coefficient.

capillary flow↗
DOE OSTI2026

Hierarchical-embedding autoencoder with a predictor as efficient architecture for learning time-evolution in multi-scale turbulent flows

We introduce a scale-aware, data-driven deep learning modeling framework for accurately predicting the time evolution of multi-scale turbulent plasma and liquid flows. The approach is motivated by the idea of scale separation. Structures of vastly different length scales emerge in these systems, and interactions between these structures occur only locally. To exploit this structure, the flow state is transformed by a hierarchical, fully convolutional autoencoder, not into a single embedding layer as in conventional convolutional surrogate models, but into a series of embedding layers. A stepwise training strategy ensures that fine-scale features are encoded on a high-resolution grid, while larger structures are represented on progressively coarser layers. The time evolution predictor advances all embedding layers in sync, capturing local interactions between features at the same scale as well as between all scales. This approach enables efficient modeling of multi-scale systems since negligible interactions between distant, small-scale structures do not need to be directly modeled. Our hierarchical-embedding autoencoder with a predictor framework is evaluated on canonical examples of multi-scale turbulence: two-dimensional Kolmogorov flow and Hasegawa–Wakatani plasma turbulence. In both cases, the proposed framework significantly improves predictive accuracy relative to conventional convolutional network architectures. A significant improvement in prediction accuracy was observed for crucial statistical characteristics of the Hasegawa–Wakatani plasma as well as for individual trajectories of the Kolmogorov flow turbulence. Importantly, the model's rollout for the Hasegawa–Wakatani problem demonstrates a four-order-of-magnitude speedup compared to traditional numerical solvers.

Khrabry, Alexander I. [Princeton Univ., NJ (United↗
NASA NTRS1945

Heat-transfer tests of aqueous ethylene glycol solutions in an electrically heated tube

As part of an investigation of the cooling characteristics of liquid-cooled engines, tests were conducted with an electrically heated single-tube heat exchanger to determine the heat-transfer characteristics of an-e-2 ethylene glycol and other ethylene glycol-water mixtures. Similar tests were conducted with water and commercial butanol (n-butyl alcohol) for check purposes. The results of tests conducted at an approximately constant liquid-flow rate of 0.67 pound per second (Reynolds number, 14,500 to 112,500) indicate that at an average liquid temperature 200 degrees f, the heat-transfer coefficients obtained using water, nominal (by volume) 30 percent-70 percent and 70 percent-30 percent glycol-water mixtures are approximately 3.8, 2.8, and 1.4 times higher, respectively, than the heat-transfer coefficients obtained using an-e-2 ethylene glycol.

Bernardo, Everett↗
NASA NTRS2006

Two Phase Flow Modeling: Summary of Flow Regimes and Pressure Drop Correlations in Reduced and Partial Gravity

The purpose of this report is to provide a summary of state-of-the-art predictions for two-phase flows relevant to Advanced Life Support. We strive to pick out the most used and accepted models for pressure drop and flow regime predictions. The main focus is to identify gaps in predictive capabilities in partial gravity for Lunar and Martian applications. Following a summary of flow regimes and pressure drop correlations for terrestrial and zero gravity, we analyze the fully developed annular gas-liquid flow in a straight cylindrical tube. This flow is amenable to analytical closed form solutions for the flow field and heat transfer. These solutions, valid for partial gravity as well, may be used as baselines and guides to compare experimental measurements. The flow regimes likely to be encountered in the water recovery equipment currently under consideration for space applications are provided in an appendix.

Balasubramaniam, R.↗
NASA NTRSDate not supplied

Visible and Infrared Imaging of Various Flow Regimes in the Flow Boiling and Condensation Experiment Transfer Line

The Flow Boiling and Condensation Experiment (FBCE) Transfer Line (TL) test module is being developed to study fluid physics of cryogenic transfer lines in microgravity. The TL module will reside in the FBCE facility located within the Fluids Integration Rack (FIR) aboard the International Space Station (ISS). TL will use the same normal perfluoro hexane (nPFH) used in the previous FBCE test sections. To simulate cryogenic line transfer in the visualization section, a sapphire tube coated with indium tin oxide (ITO) is heated via Joule heated while a bypass line is used to flow liquid nPFH at the desired inlet conditions. Once the visualization line reaches steady-state temperature and pressure conditions, flow is diverted through the heated line and chilldown begins. All flow regimes observed within a cryogenic TL are created and studied using visible imaging with diffuse backlighting to image inverted annular flow, transition, and nucleate boiling. A visible laser light sheet provided by FIR will provide a means to observe and track droplets in the dispersed flow regime. IR imaging of the visualization tube outer surface with the emissivity of the ITO coating provides the surface chilldown temperature profile. Preliminary imaging system development includes some of the components used in the Flow Boiling Module (FBM) and some new components that are easily integrated into the PC-based system but will require some refinement to operate properly on the FIR PCIe/104 imaging system. Optical design and packaging within the limited volume of the module enclosure is also presented. This paper presents FBCE-TL visible and infrared laboratory-based imaging studies and anticipated visualization capabilities of the TL module under preliminary breadboard development and under the utilization constraints within the FBCE/FIR host facility.

transfer line↗
NASA NTRS1992

Film condensation in a horizontal rectangular duct

Condensation heat transfer in an annular flow regime with and without interfacial waves was experimentally investigated. The study included measurements of heat transfer rate with condensation of vapor flowing inside a horizontal rectangular duct and experiments on the initiation of interfacial waves in condensation, and adiabatic air-liquid flow. An analytical model for the condensation was developed to predict condensate film thickness and heat transfer coefficients. Some conclusions drawn from the study are that the condensate film thickness was very thin (less than 0.6 mm). The average heat transfer coefficient increased with increasing the inlet vapor velocity. The local heat transfer coefficient decreased with the axial distance of the condensing surface, with the largest change at the leading edge of the test section. The interfacial shear stress, which consisted of the momentum shear stress and the adiabatic shear stress, appeared to have a significant effect on the heat transfer coefficients. In the experiment, the condensate flow along the condensing surface experienced a smooth flow, a two-dimensional wavy flow, and a three-dimensional wavy flow. In the condensation experiment, the local wave length decreased with the axial distance of the condensing surface and the average wave length decreased with increasing inlet vapor velocity, while the wave speed increased with increasing vapor velocity. The heat transfer measurements are reliable. And, the ultrasonic technique was effective for measuring the condensate film thickness when the surface was smooth or had waves of small amplitude.

Lu, Qing↗