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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
NASA NTRS2008

Actuated atomizer

An actuated atomizer is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated atomizer includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a magnetic field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the magnetic field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the atomizer from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the atomizer to release atomized fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the magnetic field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.

Tilton, Charles↗
NASA NTRS2009

NASA Tech Briefs, August 2009

Topics covered include: Aligning a Receiving Antenna Array to Reduce Interference; Collecting Ground Samples for Balloon-Borne Instruments; Tethered Pyrotechnic Apparatus for Acquiring a Ground Sample; Enhanced Video-Oculography System; Joint Carrier-Phase Synchronization and LDPC Decoding; Dual-Polarization, Sideband-Separating, Balanced Receiver for 1.5 THz Modular Battery Charge Controller; Efficient Multiplexer FPGA Block Structures Based on G4FETs; VLSI Microsystem for Rapid Bioinformatic Pattern Recognition; Low-Noise Amplifier for 100 to 180 GHz; Improved Fabrication of Ceramic Matrix Composite/Foam Core Integrated Structures; Inert Welding/Brazing Gas Filters and Dryers; Fabricating Copper Nanotubes by Electrodeposition; Reducing Aerodynamic Drag on Empty Open Cargo Vehicles; Rotary Percussive Auto-Gopher for Deep Drilling and Sampling; More About Reconfigurable Exploratory Robotic Vehicles; Thermostatic Valves Containing Silicone-Oil Actuators; Improving Heat Flux Performance of Flat Surface in Spray-Cooling Systems; Treating Fibrous Insulation to Reduce Thermal Conductivity; Silica-Aerogel Composites Opacified with La(sub0.7)Sr(sub0.3)MnO3; Cyclic Oxidation Behavior of CuCrAl Cold-Sprayed Coatings for Reusable Launch Vehicles; Ceramic Fiber Structures for Cryogenic Load-Bearing Applications; Elastomer Reinforced with Carbon Nanotubes; Biologically Inspired Purification and Dispersion of SWCNTs; A Technique for Adjusting Eigenfrequencies of WGM Resonators; Low-Pressure, Field-Ionizing Mass Spectrometer; Modifying Operating Cycles to Increase Stability in a LITS; Chamber for Simulating Martian and Terrestrial Environments; Algorithm for Detecting a Bright Spot in an Image; Extreme Programming: Maestro Style; Adaptive Behavior for Mobile Robots; Protocol for Communication Networking for Formation Flying; Planning Complex Sequences Using Compressed Representations; and Self-Supervised Learning of Terrain Traversability from Proprioceptive Sensors.

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NASA NTRSDate not supplied

Cryogenic Flow Boiling Parabolic Flight Experiment and Universal Correlations for Cryogens

Cryogenic fluids are employed in many industries and play crucial roles in space applications, including nuclear thermal propulsion systems, LOX/LCH4 ascent and descent stage feedlines, LOX/LH2 transfer lines for in-space fuel depots, and LHe transfer lines that cool space experiments. Due to the ultra-low boiling point of cryogens, phase change is inevitable in these systems, which leads to complex boiling behavior in reduced gravity. For cost-effective design and sizing of the aforementioned systems, accurate knowledge of two-phase parameters such as pressure drop, heat transfer coefficient (HTC), and critical heat flux (CHF) is desired. Since 2018, researchers from Purdue University and NASA Glenn Research Center (GRC) have been collaborating to investigate the effects of reduced gravity on cryogenic pool boiling, flow boiling ins tubes, and spray cooling. Using a variety of both terrestrial and parabolic flight experimental rigs, extensive LN2 data have been amassed and combined with cryogenic data from World literature to develop both ‘universal’ empirical correlations and CFD models, which are expected to serve as foundation for design of future space systems involving cryogenic fluids. This presentation will provide an overview of both the experimental work and predictive tools that have resulted from the joined Purdue-Glenn studies.

Flow Boiling↗
NASA NTRS1991

Applications of diamond films and related materials; Proceedings of the 1st International Conference, Auburn, AL, Aug. 17-22, 1991

The present conference discusses the nucleation and growth of diamond from hydrocarbons, the cutting tool performance of CVD thick-film diamond, the characterization of CVD diamond grinding powder, industrial applications of crystalline diamond-coated tools, standardized SEM tribometry of diamond-coated substrates, residual stress in CVD diamond films, the optical properties of CVD diamond films, polycrystalline diamond films for optical applications, and diamond growth on ferrous metals. Also discussed are ion beam-irradiation smoothing of diamond films, electronic circuits on diamond substrates, diamond-laminated surfaces for evaporative spray cooling, electron devices based on the unique properties of diamond, diamond cold cathodes, thin-film diamond microstructure applications, Schottky diodes from flame-grown diamond, diamond films for thermionic applications, methods of diamond nucleation and selective deposition, high-rate/large-area diamond film production, halogen-assisted diamond growth, the economics of diamond technology, and the optical and mechanical properties of diamondlike films.

Tzeng, Yonhua↗
NASA NTRS2016

Modeling Droplet Heat and Mass Transfer during Spray Bar Pressure Control of the Multipurpose Hydrogen Test Bed (MHTB) Tank in Normal Gravity

A CFD model for simulating pressure control in cryogenic storage tanks through the injection of a subcooled liquid into the ullage is presented and applied to the 1g MHTB spray bar cooling experiments. An Eulerian-Lagrangian approach is utilized to track the spray droplets and capture the interaction between the discrete droplets and the continuous ullage phase. The spray model is coupled with the VOF model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. A new model for calculating the droplet-ullage heat and mass transfer is developed. In this model, a droplet is allowed to warm up to the saturation temperature corresponding to the ullage vapor pressure, after which it evaporates while remaining at the saturation temperature. The droplet model is validated against the results of the MHTB spray-bar cooling experiments with 50% and 90% tank fill ratios. The predictions of the present T-sat based model are compared with those of a previously developed kinetic-based droplet mass transfer model. The predictions of the two models regarding the evolving tank pressure and temperature distributions, as well as the droplets' trajectories and temperatures, are examined and compared in detail. Finally, the ullage pressure and local vapor and liquid temperature evolutions are validated against the corresponding data provided by the MHTB spray bar mixing experiment.

mass transfer↗
NASA NTRS1979

Evaporative cooling on a grooved surface

The transition point where water begins to accumulate on the surface during spray evaporative cooling was investigated experimentally to determine the temperatures and corresponding heat flux at which this transition occurs. Several pressure ranges were considered including one below the triple point of water. Additionally, the results using a grooved surface were compared to those using a smooth surface. It was determined that a grooved surface has no effect on the heat transfer.

Yoder, D.↗
NASA NTRS1973

An Apollo compatible cloud physics experiment.

Consideration of the utilization of a low-gravity environment to obtain experimental information, in the area of cloud microphysics, which cannot be obtained in ground laboratories. The experiment discussed is designed to obtain quantitative answers about evaporation and breakup of salt particles from ocean spray and other sources. In addition to salt nuclei distribution mechanisms, this breakup has ecological importance in relation to the spreading of salt mists from salted highways and spreading of brine cooling tower spray from electrical power generation plants. This experiment is being submitted for consideration on the Apollo-Soyuz Test Program in 1975.

Eaton, L. R.↗
NASA NTRS1979

A fundamental study of liquid spray evaporation at a heated surface

The influence of feedwater temperature and the influence of pulsing nozzle flow on the heat transfer characteristics in the spray evaporative cooling process were investigated. A commercial water circulation heater was installed in the feedwater line between the supply reservoir and the nozzle. A pass through the heater provided water at temperatures up to 50 C at the nozzle; higher temperatures were obtained by multiple heater passes. A thermocouple installed in the water line just upstream of the nozzle provided a measure of the feedwater temperature. Initial tests were run with belljar exhaust orifice number two which provided a pressure in a range about 7mm Hg abs. The feedwater temperature was heated to a temperature of 45 C. Results indicate that for a given system operating pressure, there is an upper limit on the feedwater temperature above which the spray will flash to vapor before hitting the surface to be cooled.

Wierum, F. A.↗
NASA NTRS2003

Vacuum Plasma Spray Forming of Copper Alloy Liners for Regeneratively Cooled Liquid Rocket Combustion Chambers

Vacuum plasma spray (VPS) has been demonstrated as a method to form combustion chambers from copper alloys NARloy-Z and GRCop-84. Vacuum plasma spray forming is of particular interest in the forming of CuCrNb alloys such as GRCop-84, developed by NASA s Glenn Research Center, because the alloy cannot be formed using conventional casting and forging methods. This limitation is related to the levels of chromium and niobium in the alloy, which exceed the solubility limit in copper. Until recently, the only forming process that maintained the required microstructure of CrNb intermetallics was powder metallurgy formation of a billet from powder stock, followed by extrusion. This severely limits its usefulness in structural applications, particularly the complex shapes required for combustion chamber liners. This paper discusses the techniques used to form combustion chambers from CuCrNb and NARloy-Z, which will be used in regeneratively cooled liquid rocket combustion chambers.

Zimmerman, Frank↗
NASA NTRSDate not supplied

Modeling Self-Pressurization and Spray Bar Pressure Control of a Cryogenic Storage Tank in Normal Gravity

This paper presents Computational Fluid Dynamics (CFD) models for simulating self-pressurization and spray bar cooling processes in a large-scale liquid hydrogen storage tank under normal gravity. The self-pressurization model utilizes the kinetics-based Schrage equation with the Volume-Of-Fluid (VOF) model to account for the evaporative and condensing interfacial mass fluxes. It uses a laminar approach to model natural convection and compares the pressures and temperatures predicted by the CFD model with experimental data from the Multipurpose Hydrogen Test Bed (MHTB) self-pressurization experiment. Additionally, the predicted interfacial mass flux is presented. A CFD model for simulating pressure control using a spray bar is also presented. An Eulerian-Lagrangian approach models the interactions between the discrete droplets and the continuous ullage phase. The spray model is coupled with the VOF model by tracking particles in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. The T-sat model is used to calculate the droplet-ullage heat and mass transfer. In this model, droplets warm up to the saturation temperature corresponding to the ullage vapor pressure thereafter evaporating while remaining at the saturation temperature. The tank pressure, vapor, and liquid temperature evolutions are validated against data from the MHTB spray bar mixing experiment.

Self-Pressurization↗
NASA NTRS2015

CFD Modeling of the Multipurpose Hydrogen Test Bed (MHTB) Self-Pressurization and Spray Bar Mixing Experiments in Normal Gravity: Effect of Accommodation Coefficient on the Tank Pressure

In this paper, a computational model that describes pressure control phase of a typical MHTB experiment will be presented. The fidelity of the model will be assessed by comparing the models predictions with MHTB experimental data. In this paper CFD results for MHTB spray bar cooling case with 50 tank fill ratio will be presented and analyzed. Effect of accommodation coefficient for calculating droplet-ullage mass transfer will be evaluated.

cryogenic fluid storage↗
NASA NTRS1978

Liquid-cooling technology for gas turbines - Review and status

After a brief review of past efforts involving the forced-convection cooling of gas turbines, the paper surveys the state of the art of the liquid cooling of gas turbines. Emphasis is placed on thermosyphon methods of cooling, including those utilizing closed, open, and closed-loop thermosyphons; other methods, including sweat, spray and stator cooling, are also discussed. The more significant research efforts, design data, correlations, and analytical methods are mentioned and voids in technology are summarized.

Van Fossen, G. J., Jr.↗
NASA NTRS2015

Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

Spray Cooling↗
NASA NTRS2008

Feasibility of Conducting J-2X Engine Testing at the Glenn Research Center Plum Brook Station B-2 Facility

A trade study of the feasibility of conducting J-2X testing in the Glenn Research Center (GRC) Plum Brook Station (PBS) B-2 facility was initiated in May 2006 with results available in October 2006. The Propulsion Test Integration Group (PTIG) led the study with support from Marshall Space Flight Center (MSFC) and Jacobs Sverdrup Engineering. The primary focus of the trade study was on facility design concepts and their capability to satisfy the J-2X altitude simulation test requirements. The propulsion systems tested in the B-2 facility were in the 30,000-pound (30K) thrust class. The J-2X thrust is approximately 10 times larger. Therefore, concepts significantly different from the current configuration are necessary for the diffuser, spray chamber subsystems, and cooling water. Steam exhaust condensation in the spray chamber is judged to be the key risk consideration relative to acceptable spray chamber pressure. Further assessment via computational fluid dynamics (CFD) and other simulation capabilities (e.g. methodology for anchoring predictions with actual test data and subscale testing to support investigation.

Schafer, Charles F.↗
NASA NTRS1988

High-Emissivity Coatings For High-Temperature Surfaces

Plasma-sprayed coatings increase cooling by thermal radiation. Coating of zirconium diboride on tungsten or molybdenum increases emissivity of surface to more than 0.6 at 2,000 degree C. Applied by plasma-arc spraying after surface cleaned and roughened to ensure adhesion.

Deininger, William D.↗
NASA NTRS1986

Thermocapillary Convection in Liquid Droplets

The purpose of this video is to understand the effects of surface tension on fluid convection. The fluid system chosen is the liquid sessile droplet to show the importance in single crystal growth, the spray drying and cooling of metal, and the advance droplet radiators of the space stations radiators. A cross sectional representation of a hemispherical liquid droplet under ideal conditions is used to show internal fluid motion. A direct simulation of buoyancy-dominant convection and surface tension-dominant convection is graphically displayed. The clear differences between two mechanisms of fluid transport, thermocapillary convection, and bouncy dominant convection is illustrated.

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