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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Silicon Carbide-Based Hydrogen and Hydrocarbon Gas Detection

Hydrogen and hydrocarbon detection in aeronautical applications is important for reasons of safety and emissions control. The use of silicon carbide as a semiconductor in a metal-semiconductor or metal-insulator-semiconductor structure opens opportunities to measure hydrogen and hydrocarbons in high temperature environments beyond the capabilities of silicon-based devices. The purpose of this paper is to explore the response and stability of Pd-SiC Schottky diodes as gas sensors in the temperature range from 100 to 400 C. The effect of heat treating on the diode properties as measured at 100 C is explored. Subsequent operation at 400 C demonstrates the diodes' sensitivity to hydrogen and hydrocarbons. It is concluded that the Pd-SiC Schottky diode has potential as a hydrogen and hydrocarbon sensor over a wide range of temperatures but further studies are necessary to determine the diodes' long term stability.

Hunter, Gary W.↗
NASA NTRS1997

Development of High Temperature Gas Sensor Technology

The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

Hunter, Gary W.↗
NASA NTRS2017

Large Scale Production of Densified Hydrogen Using Integrated Refrigeration and Storage

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage (IRAS) technology at NASA Kennedy Space Center led to the production of large quantities of solid densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. System energy balances and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing (up to 1 K), and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. Twenty silicon diode temperature sensors were recorded over approximately one month for testing at two different fill levels (33 67). The phenomenon, observed at both two fill levels, is described and presented detailed and explained herein., and The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Notardonato, William U.↗
NASA NTRS1997

Method and Apparatus for the Detection of Hydrogen Using a Metal Alloy

A hydrogen sensitive metal alloy contains palladium and titanium to provide a larger change in electrical resistance when exposed to the presence of hydrogen. The alloy is deposited on a substrate and a thin film and connected across electrical circuitry to provide a sensor device that can be used for improved sensitivity and accuracy of hydrogen detection.

Hunter, Gary W.↗
DOE OSTI2024

Warrick Conductivity Level Controllers Series 3H

This is my internship poster. In the poster I talk about the level controllers that I wired together and installed to support electrolysis testing systems in efforts to make the systems more efficient and run based on the communication between devices to ensure a closed loop system that can run on its own in a safe and controlled manner. I included pictures of some of the wiring as well as the level sensor devices and relays. I also included pictures of the tanks that will be filled at different heights with deionized water based on where the level sensors are.

08 HYDROGEN↗
DOE OSTI2024

Cellular Phosphate Sensing and Anion Binding by an Azacrown‐Calixpyrrole Hybrid

A hybrid receptor-sensor for anions originating from the merging of positively charged ammonium moieties for electrostatic attraction/stronger binding of azacrowns with directionality of calixpyrrole hydrogen bond donors for selectivity is investigated. As demonstrated this hybrid receptor-sensor shows a remarkable selectivity for orthophosphate even in the presence of other phosphates and anions found in cellular materials (K assoc H 2 PO 4 − >H 2 P 2 O 7 2− >AMP − ≫ADP 2− or ATP 3− over halides, nitrate, or hydrogen sulfate; all Na + salts in water) but also cellular polyphosphate or phospholipids. This selectivity is harnessed in a real-time monitoring of cell lysis by lysozyme, which releases orthophosphate and other phosphates and anions from the cells. This sensitive (LOD 0.4 μM) fluorescence-based microscale method compares favorably with the state-of-the-art techniques but can easily be practiced in a high-throughput screening (HTS) manner. The anion binding and selectivity in aqueous solutions were investigated by NMR and put in context with phosphate binding of the parent calix[4]pyrrole. The microscopic understanding of anion binding by the hybrid receptor was then obtained from a combination of density functional theory (DFT), classical molecular dynamics (MD) with explicit water solvation, and ab initio MD (AIMD) simulations. Correlating the NMR and fluorescence binding data with studies of solvation of the receptor, phosphate anion, and the resulting complex confirms the binding is largely driven by entropic component (TΔS) associated with receptor and anion desolvation.

Anions↗
DOE OSTI2020

A Novel Laser 3D Printing Method for the Advanced Manufacturing of Protonic Ceramics

Protonic ceramics (PCs) with high proton conductivity at intermediate temperatures (300–600 °C) have attracted many applications in energy conversion and storage devices such as PC fuel/electrolysis cells, PC membrane reactors, hydrogen pump, hydrogen or water-permeable membranes, and gas sensors. One of the essential steps for fulfilling the practical utilization of these intermediate-temperature PC energy devices is the successful development of advanced manufacturing methods for cost-effectively and rapidly fabricating them with high energy density and efficiency in a customized demand. In this work, we developed a new laser 3D printing (L3DP) technique by integrating digital microextrusion-based 3D printing and precise and rapid laser processing (sintering, drying, cutting, and polishing), which showed the capability of manufacturing PCs with desired complex geometries, crystal structures, and microstructures. The L3DP method allowed the fabrication of PC parts such as pellets, cylinders, cones, films, straight/lobed tubes with sealed endings, microchannel membranes, and half cells for assembling PC energy devices. The preliminary measurement of the L3DP electrolyte film showed a high proton conductivity of ≈7 × 10−3 S/cm. This L3DP technique not only demonstrated the potential to bring the PCs into practical use but also made it possible for the rapid direct digital manufacturing of ceramic-based devices.

08 HYDROGEN↗
DOE OSTI2025

Development of a Digital Twin for Hydrogen Dispersion and Safety Assessment in an Electrolyzer Based Hydrogen Production Facility

Digital twin models are virtual representations of physical systems that use real-time data to simulate and optimize performance. This study presents the development and initial implementation of a digital twin (DT) for the electrolyzer-based hydrogen production facility at NREL's Advanced Research on Integrated Energy Systems (ARIES), focused on enhancing safety and optimizing sensor placement through physics-based simulations and metadata integration. The DT incorporates detailed facility-specific information, including component layout, leak locations, and controlled release parameters, to model hydrogen dispersion under varying environmental conditions. Using steady-state computational fluid dynamics (CFD) simulations informed by real meteorological data, such as wind speed, direction, and vertical wind profiles, the DT enables visualization of hydrogen plume behavior and spatial concentration distributions. Comparative analysis between high and low wind speed scenarios illustrates the significant influence of wind dynamics on plume shape and extent, with horizontal momentum dominating dispersion at higher speeds, while buoyancy effects become more prominent under low wind conditions. These simulations generate a rich dataset embedded within the DT, allowing users to assess potential leak outcomes and identify optimal sensor locations based on concentration thresholds. The model supports scenario-based analysis to guide safety strategies and equipment deployment for open-area hydrogen infrastructure. The digital twin thus serves as a dynamic platform for virtual prototyping, providing predictive insight into hydrogen behavior and enhancing risk-informed decision-making. This initial phase establishes a validated foundation for future integration of transient, uncontrolled leak scenarios and real-time sensor feedback, positioning the DT as a critical tool for safety design, operational planning, and adaptive monitoring in hydrogen systems. Overall, the approach demonstrates the value of combining environmental data with digital simulations to inform safer and more efficient deployment of hydrogen technologies.

08 HYDROGEN↗
NASA NTRS2006

Intelligent Chemical Sensor Systems for In-space Safety Applications

Future in-space and lunar operations will require significantly improved monitoring and Integrated System Health Management (ISHM) throughout the mission. In particular, the monitoring of chemical species is an important component of an overall monitoring system for space vehicles and operations. For example, in leak monitoring of propulsion systems during launch, inspace, and on lunar surfaces, detection of low concentrations of hydrogen and other fuels is important to avoid explosive conditions that could harm personnel and damage the vehicle. Dependable vehicle operation also depends on the timely and accurate measurement of these leaks. Thus, the development of a sensor array to determine the concentration of fuels such as hydrogen, hydrocarbons, or hydrazine as well as oxygen is necessary. Work has been on-going to develop an integrated smart leak detection system based on miniaturized sensors to detect hydrogen, hydrocarbons, or hydrazine, and oxygen. The approach is to implement Microelectromechanical Systems (MEMS) based sensors incorporated with signal conditioning electronics, power, data storage, and telemetry enabling intelligent systems. The final sensor system will be self-contained with a surface area comparable to a postage stamp. This paper discusses the development of this "Lick and Stick" leak detection system and it s application to In-Space Transportation and other Exploration applications.

Hunter, G. W.↗
NASA NTRS2012

Chemochromic detector for sensing gas leakage and process for producing the same

A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment mechanically mixed with a polymer and formed into a rigid or pliable material. In a preferred embodiment, the chemochromic detector includes aerogel material. The detector is robust and easily modifiable for a variety of applications and environmental conditions, such as atmospheres of inert gas, hydrogen gas, or mixtures of gases, or in environments that have variable temperature, including high temperatures such as above 100.degree. C. and low temperatures such as below -196.degree. C.

Roberson, Luke B.↗
NASA NTRS2014

Chemochromic Detector for Sensing Gas Leakage and Process for Producing the Same

A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment mechanically mixed with a polymer and molded into a rigid or pliable shape. In a preferred embodiment, the chemochromic detector is within the material which is molded into a manufactured part, said part becoming the detector itself. The detector is robust and easily modifiable for a variety of applications and environmental conditions, such as atmospheres of inert gas, hydrogen gas, or mixtures of gases, or in environments that have variable temperature, including high temperatures such as above 100 C. and low temperatures such as below -196 C.

Roberson, Luke B.↗
NASA NTRS2015

Chemochromic Detector for Sensing Gas Leakage and Process for Producing the Same

A chemochromic sensor for detecting a combustible gas, such as hydrogen, includes a chemochromic pigment and a textile polymer. The textile material includes a chemochromic pigment operably responsive to a combustible gas. The combustible gas sensing textile material can be made by melt spinning, solution spinning, or other similar techniques. In a preferred embodiment carbon nanotubes are used with the textile material which will increase the material strength and alter the thermal and/or electrical properties. These textiles woven into fabrics can provide garments not only with hydrogen sensing capabilities but the carbon nanotubes will allow for a range of sensing capabilities to be embedded (i.e. gas, health, and electronic monitors) within the garments.

Roberson, Luke B.↗
NASA NTRS1995

Increasing Precision Of Temperature Sensors Of Liquid H2

Commercial silicon-diode temperature sensors intended for use in boiling or nearly boiling liquid hydrogen at temperatures near 37 degrees R recalibrated to greater precision by method involving careful attention to details of design, operation, and computation. Method based on fundamental electrical and thermodynamic principles and good engineering practice, also applicable to recalibration of other temperature sensors intended for use in other boiling or nearly boiling liquids.

Dempsey, Paula J.↗
NASA NTRS2012

NASA Tech Briefs, October 2012

Topics discussed include: Detection of Chemical Precursors of Explosives; Detecting Methane From Leaking Pipelines and as Greenhouse Gas in the Atmosphere; Onboard Sensor Data Qualification in Human-Rated Launch Vehicles; Rugged, Portable, Real-Time Optical Gaseous Analyzer for Hydrogen Fluoride; A Probabilistic Mass Estimation Algorithm for a Novel 7-Channel Capacitive Sample Verification Sensor; Low-Power Architecture for an Optical Life Gas Analyzer; Online Cable Tester and Rerouter; A Three-Frequency Feed for Millimeter-Wave Radiometry; Capacitance Probe Resonator for Multichannel Electrometer; Inverted Three-Junction Tandem Thermophotovoltaic Modules; Fabrication of Single Crystal MgO Capsules; Inflatable Hangar for Assembly of Large Structures in Space; Mars Aqueous Processing System; Hybrid Filter Membrane; Design for the Structure and the Mechanics of Moballs; Pressure Dome for High-Pressure Electrolyzer; Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings; Compact, Low-Force, Low-Noise Linear Actuator; Ultra-Compact Motor Controller; Extreme Ionizing-Radiation-Resistant Bacterium; Wideband Single-Crystal Transducer for Bone Characterization; Fluorescence-Activated Cell Sorting of Live Versus Dead Bacterial Cells and Spores; Nonhazardous Urine Pretreatment Method; Laser-Ranging Transponders for Science Investigations of the Moon and Mars; Ka-Band Waveguide Three-Way Serial Combiner for MMIC Amplifiers; Structural Health Monitoring with Fiber Bragg Grating and Piezo Arrays; Low-Gain Circularly Polarized Antenna with Torus-Shaped Pattern; Stereo and IMU- Assisted Visual Odometry for Small Robots; Global Swath and Gridded Data Tiling; GOES-R: Satellite Insight; Aquarius iPhone Application; Monitoring of International Space Station Telemetry Using Shewhart Control Charts; Theory of a Traveling Wave Feed for a Planar Slot Array Antenna; Time Manager Software for a Flight Processor; Simulation of Oxygen Disintegration and Mixing With Hydrogen or Helium at Supercritical Pressure; A Superfluid Pulse Tube Refrigerator Without Moving Parts for Sub-Kelvin Cooling; Sapphire Viewports for a Venus Probe; The Mobile Chamber; Electric Propulsion Induced Secondary Mass Spectroscopy; and Radiation-Tolerant DC-DC Converters.

Source record↗
NASA NTRSDate not supplied

Exploring Cryogenic Propellant Behavior in Low-Gravity Environments, Insights from the Saturn AS-203 Vent Experiments and CFD Analysis

In the 1960s, NASA embarked on a series of groundbreaking flight tests on the Saturn AS-203, aiming to understand the complex dynamics of propellants in the distinctive low-gravity lunar environment. These tests centered on venting experiments, subjecting cryogenic liquid hydrogen to conditions beneath its saturation pressure while accelerating the vehicle to manage the propellant's positioning. During these experiments, NASA meticulously scrutinized the propellant tank using a suite of instruments, including temperature and pressure sensors, as well as a camera placed internal to the liquid hydrogen tank. The outcomes provided anecdotal evidence revealing the phenomenon of boiling along the tank's walls and the intriguing formation of liquid globules and droplets in the ullage during the venting process. Notably, the substantial drop in liquid temperature during these tests suggests adiabatic cooling as liquid hydrogen evaporates. This evaporation leads to a cooling of the remaining hydrogen due to the heat it releases. This paper presents the outcomes of our initial analysis, wherein CFD models were used to simulate the observed boiling phenomena and the bulk movement of the liquid hydrogen propellant, both qualitatively and quantitatively. The implications of these findings may extend to mission and vehicle designers, providing invaluable insights for crafting more efficient and effective in-space propulsion systems utilizing cryogenic propellant including impacts to vehicle control systems. Understanding propellant behavior under these conditions may better inform GNC teams, ensuring more stable vehicle operations when utilizing cryogenic propellants. This includes essential considerations for cryogenic propellant transfer and storage systems, integral to NASA's forthcoming Artemis missions. While we recognize the challenges tied to CFD models, this study represents a step forward, highlighting current progress and signaling the potential for refining our predictive understanding in the future.

Computational Fluid Dynamics↗
NASA NTRSDate not supplied

Exploring Cryogenic Propellant Behavior in Low-Gravity Environments, Insights from the Saturn AS-203 Vent Experiments and CFD Analysis

In the 1960s, NASA embarked on a series of groundbreaking flight tests on the Saturn AS-203, aiming to understand the complex dynamics of propellants in the distinctive low-gravity lunar environment. These tests centered on venting experiments, subjecting cryogenic liquid hydrogen to conditions beneath its saturation pressure while accelerating the vehicle to manage the propellant's positioning. During these experiments, NASA meticulously scrutinized the propellant tank using a suite of instruments, including temperature and pressure sensors, as well as a camera placed internal to the liquid hydrogen tank. The outcomes provided anecdotal evidence revealing the phenomenon of boiling along the tank's walls and the intriguing formation of liquid globules and droplets in the ullage during the venting process. Notably, the substantial drop in liquid temperature during these tests suggests adiabatic cooling as liquid hydrogen evaporates. This evaporation leads to a cooling of the remaining hydrogen due to the heat it releases. This paper presents the outcomes of our initial analysis, wherein CFD models were used to simulate the observed boiling phenomena and the bulk movement of the liquid hydrogen propellant, both qualitatively and quantitatively. The implications of these findings may extend to mission and vehicle designers, providing invaluable insights for crafting more efficient and effective in-space propulsion systems utilizing cryogenic propellant including impacts to vehicle control systems. Understanding propellant behavior under these conditions may better inform GNC teams, ensuring more stable vehicle operations when utilizing cryogenic propellants. This includes essential considerations for cryogenic propellant transfer and storage systems, integral to NASA's forthcoming Artemis missions. While we recognize the challenges tied to CFD models, this study represents a step forward, highlighting current progress and signaling the potential for refining our predictive understanding in the future.

Computational Fluid Dynamics↗
DOE OSTI2026

Development of a Digital Twin for Hydrogen Dispersion and Safety Assessment in an Electrolyzer-Based Hydrogen Production Facility: Preprint

Digital twin models are virtual representations of physical systems that use real-time data to simulate and optimize performance. This study presents the development and initial implementation of a digital twin (DT) for the electrolyzer-based hydrogen production facility at the National Renewable Energy Laboratory (NREL)'s Advanced Research on Integrated Energy Systems (ARIES), focused on enhancing safety and optimizing sensor placement through physics-based simulations and metadata integration. The DT incorporates detailed facility-specific information, including component layout, leak locations, and controlled release parameters, to model hydrogen dispersion under varying environmental conditions. Using steady-state computational fluid dynamics (CFD) simulations informed by real meteorological data, such as wind speed, direction, and vertical wind profiles, the DT enables visualization of hydrogen plume behavior and spatial concentration distributions. Comparative analysis between high and low wind speed scenarios illustrates the significant influence of wind dynamics on plume shape and extent, with horizontal momentum dominating dispersion at higher speeds, while buoyancy effects become more prominent under low wind conditions. These simulations generate a rich dataset embedded within the DT, allowing users to assess potential leak outcomes and identify optimal sensor locations based on concentration thresholds. The model supports scenario-based analysis to guide safety strategies and equipment deployment for open-area hydrogen infrastructure. The digital twin thus serves as a dynamic platform for virtual prototyping, providing predictive insight into hydrogen behavior and enhancing risk-informed decision-making. This initial phase establishes a validated foundation for future integration of transient, uncontrolled leak scenarios and real-time sensor feedback, positioning the DT as a critical tool for safety design, operational planning, and adaptive monitoring in hydrogen systems. Overall, the approach demonstrates the value of combining environmental data with digital simulations to inform safer and more efficient deployment of hydrogen technologies.

08 HYDROGEN↗