Search NASA⌕ Search

SEARCH · Search NASA

Results for “temperature sensing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Cascaded Sapphire Fiber Bragg Gratings Inscribed by Femtosecond Laser for Molten Steel Studies

This research reports a distributed fiber optic high-temperature sensing system tailored for applications in the steel industry and various other sectors. Recent advancements in optical sensor technology have led to the exploration of sapphire crystal fibers as a solution for sensing in harsh environments. Utilizing a femtosecond (fs) laser, cascaded fiber Bragg gratings (FBGs) were meticulously fabricated within a multimode sapphire optical fiber. These FBGs endowed the system with distributed sensing capabilities and underwent rigorous testing under extreme temperatures, reaching up to 1800 °C. Here, the study delves into the investigation of the FBG reflection spectrum, facilitated by the development of a sophisticated multimode demodulation system, which contributed to the attainment of precise temperature measurements with a performance accuracy of 99.9%. Demonstrating exceptional thermal stability, the sapphire FBGs endured temperatures of 1600 °C for a sustained duration of 22 h. Furthermore, this article explores the application of distributed temperature sensing employing multiple sapphire FBGs, showcasing their utility in temperature measurements related to molten steel studies.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Frequency‐Locked Wireless Multifunctional Surface Acoustic Wave Sensors

Abstract Surface acoustic waves (SAWs) have shown great potential for developing sensors for structural health monitoring (SHM) and lab‐on‐a‐chip (LOC) applications. Existing SAW sensors mainly rely on measuring the frequency shifts of high‐frequency (e.g., >0.1 GHz) resonance peaks. This study presents frequency‐locked wireless multifunctional SAW sensors that enable multiple wireless sensing functions, including strain sensing, temperature measurement, water presence detection, and vibration sensing. These sensors leverage SAW resonators on piezoelectric chips, inductive coupling‐based wireless power transmission, and, particularly, a frequency‐locked wireless sensing mechanism that works at low frequencies (e.g., <0.1 GHz). This mechanism locks the input frequency on the slope of a sensor's reflection spectrum and monitors the reflection signal's amplitude change induced by the changes of sensing parameters. The proof‐of‐concept experiments show that these wireless sensors can operate in a low‐power active mode for on‐demand wireless strain measurement, temperature sensing, and water presence detection. Moreover, these sensors can operate in a power‐free passive mode for vibration sensing, with results that agree well with laser vibrometer measurements. It is anticipated that the designs and mechanisms of the frequency‐locked wireless SAW sensors will inspire researchers to develop future wireless multifunctional sensors for SHM and LOC applications.

Bo, Luyu↗
NASA NTRS2021

Novel Fiber Optic Sensing Arrays with Enhanced Sensitivity in Cryogenic Temperatures

State-of-the-art instrumentation techniques have provided an opportunity to obtain greater insight into the characteristics of cryogenic liquid storage. Optical fiber sensors that utilize fiber Bragg gratings are a viable option for temperature sensing in volatile liquid such as liquid oxygen because there is no risk of electrical sparking and no electromagnetic interference. The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (Edwards, California) has developed a novel, simple-to-fabricate fiber array sensor that has been tested and found to be three times more sensitive than typical fiber sensors under cryogenic condition (traditional fiber sensors can suffer from reduced sensitivity below 100 K). Cryogenic temperature monitoring using the NASA fiber optic sensing system is demonstrated in a simulated cryostatic condition, as well as in an elevated pressure environment under liquid nitrogen. Measurement accuracy is compared with traditional silicon diodes. Instrument installation, sensor characteristics, and experimental results are discussed in detail.

Hon Man Chan↗
DOE OSTI2022

High Temperature Thick Film Sensor Development Based on Refractory Oxide Semiconductors

Solid-state, high-temperature sensing devices are required for accurate temperature, strain/stress, and failure monitoring for a range of advanced manufacturing, transportation, and military applications. High temperature conditions limit sensing strategies, where typically traditional metal and semiconductor materials are unstable, and the sensing options are limited to optical spectroscopy methods. In addition, strategies to embed the sensors directly within active components and protective thermal refractory are of interest that permit near-environment sensing which is not possible with the traditional electronic materials and components. Rare-earth chromite semiconductors exhibit some properties of interest for high temperature sensing technologies, such as: high microstructure and chemical stability, relatively high electronic conductivity at high temperatures, and relative thermal expansion coefficient matching to refractory thermal protective insulation (such as high-zirconia and -alumina ceramics). In this work, n-type and p-type doped lanthanum chromites compositions were computationally modelled and prepared, and the electrical, thermoelectric, and thermomechanical properties were measured for the obtained material systems. A few compositions were then processed into thick film health and temperature sensors and tested at high temperatures. To establish relative stability under harsh environment conditions, post- mortem microstructure and chemical composition was characterized after extended and cycle testing at high temperatures.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1992

Ultra-high temperature stability Joule-Thomson cooler with capability to accomodate pressure variations

A Joule-Thomson cryogenic refrigeration system capable of achieving high temperature stabilities in the presence of varying temperature, atmospheric pressure, and heat load is provided. The Joule-Thomson cryogenic refrigeration system includes a demand flow Joule-Thomson expansion valve disposed in a cryostat of the refrigeration system. The expansion valve has an adjustable orifice that controls the flow of compressed gas therethrough and induces cooling and partial liquefaction of the gas. A recuperative heat exchanger is disposed in the cryostat and coupled to the expansion valve. A thermostatically self-regulating mechanism is disposed in the cryostat and coupled to the J-T expansion valve. The thermostatically self-regulating mechanism automatically adjusts the cross sectional area of the adjustable valve orifice in response to environmental temperature changes and changes in power dissipated at a cold head. A temperature sensing and adjusting mechanism is coupled to a cold head for adjusting the temperature of the cold head in response to the change in heat flow in the cold head. The temperature sensing and adjusting mechanism comprises a temperature sensitive diode, a wound wire heater, and an electrical feedback control circuit coupling the diode to the heater. An absolute pressure relief valve is interposed between the output of the cryostat and an exhaust port for maintaining a constant exhaust temperature in the refrigerating system, independent of the changes in atmospheric pressure.

Bard, Steven↗
DOE OSTI2020

Compact absorptivity measurement system for additive manufacturing

The present disclosure relates to a powdered bed fusion additive manufacturing (PBFAM) apparatus. The apparatus uses a container for holding a quantity of powdered material. The container has a bottom wall for supporting the powdered material, wherein the bottom wall is made from the same material as the powdered material. A temperature sensing subsystem is coupled to a portion of the container for detecting a temperature of the container. A laser generates an optical beam directed at the powdered material held by the container for melting the powdered material. A controller receives temperature information from the temperature sensing subsystem and determines an absorptivity of the powdered material based on the temperature information.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Wireless Passive Ceramic Sensor for Far-Field Temperature Measurement at High Temperatures

A passive wireless high-temperature sensor for far-field applications was developed for stable temperature sensing up to 1000 °C. The goal is to leverage the properties of electroceramic materials, including adequate electrical conductivity, high-temperature resilience, and chemical stability in harsh environments. Initial sensors were fabricated using Ag for operation to 600 °C to achieve a baseline understanding of temperature sensing principles using patch antenna designs. Fabrication then followed with higher temperature sensors made from (In, Sn) O2 (ITO) for evaluation up to 1000 °C. A patch antenna was modeled in ANSYS HFSS to operate in a high-frequency region (2.5–3.5 GHz) within a 50 × 50 mm2 confined geometric area using characteristic material properties. The sensor was fabricated on Al2O3 using screen printing methods and then sintered at 700 °C for Ag and 1200 °C for ITO in an ambient atmosphere. Sensors were evaluated at 600 °C for Ag and 1000 °C for ITO and analyzed at set interrogating distances up to 0.75 m using ultra-wideband slot antennas to collect scattering parameters. The sensitivity (average change in resonant frequency with respect to temperature) from 50 to 1000 °C was between 22 and 62 kHz/°C which decreased as interrogating distances reached 0.75 m.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Machine Learning-Guided Design of Perovskite Oxides for High-Temperature Oxygen Sensing

Presentation slides for 2025 MRS Fall Meeting & Exhibit. Reliable oxygen sensors are vital for high temperature applications including combustion engines, steel production, and petrochemical refining, yet identifying stable, high-performance materials for such environments remain challenge. We apply machine learning (ML) to predict the atmospheric oxygen partial pressure–dependent conductivity of perovskite oxides, combining data from the Materials Project and published datasets.

high temperature gas sensor↗
NASA NTRS1994

Optical Fibers Would Sense Local Temperatures

Proposed fiber-optic transducers measure local temperatures. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift sensitive to temperature. Phase shifts in two-mode fibers vary with temperatures.

Egalon, Claudio O.↗
NASA NTRS2003

Simultaneous Temperature and Strain Sensing for Cryogenic Applications Using Dual-Wavelength Fiber Bragg Gratings

A new technique has been developed for sensing both temperature and strain simultaneously by using dual-wavelength fiber-optic Bragg gratings. Two Bragg gratings with different wavelengths were inscribed at the same location in an optical fiber to form a sensor. By measuring the wavelength shifts that resulted from the fiber being subjected to different temperatures and strains, the wavelength-dependent thermo-optic coefficients and photoelastic coefficients of the fiber were determined. This enables the simultaneous measurement of temperature and strain. In this study, measurements were made over the temperature range from room temperature down to about 10 K, addressing much of the low temperature range of cryogenic tanks. A structure transition of the optical fiber during the temperature change was found. This transition caused splitting of the waveforms characterizing the Bragg gratings, and the determination of wavelength shifts was consequently complicated. The effectiveness and sensitivities of these measurements in different temperature ranges are also discussed.

Wu, Meng-Chou↗
DOE OSTI2024

System and method for multi-channel pyrometer allowing non-contact temperature measurements down to 800 K on the microsecond scale

The present disclosure relates to a system for sensing temperature changes on a microsecond scale. The system uses a multi-channel pyrometer that works in the NIR spectrum to receive thermal radiation. Each channel includes an interference filter tuned to pass thermal radiation within a specified wavelength range, and a detector. Each detector detects thermal radiation focused on it. Each channel further includes an interference filter which reflects thermal radiation which does not pass through it to a subsequent downstream interference filter of a subsequent channel. Each subsequent interference filter is oriented to reflect the thermal radiation not passing through it to a next downstream one of the subsequent interference filters. A subsystem is included for receiving the output from the detectors and determining sensed temperature data therefrom, allowing measurement of temperatures down to 800 K.

Montgomery, Jeffrey↗
DOE OSTI2025

High sensitivity pressure and temperature quantum sensing in pentacene-doped p-terphenyl single crystals

Quantum sensors’ responsiveness to their physical environment enables detection of variables such as temperature (T), pressure (P), and strain. We present a molecular platform for PT sensing using para-terphenyl crystals doped with pentacene (PDP), leveraging optically detected magnetic resonance (ODMR) of photoexcited triplet electron spins. We observe maximal frequency variations of df/dP=1.8 MHz/bar from 0-8 bar and df/dT=247 kHz/K from 79–330 K, over 1200 times and threefold greater, respectively, than those seen with nitrogen-vacancy centers in diamond and > 85-fold greater pressure sensitivity over the previous record. Density functional theory calculations indicate picometer-level PT-induced molecular orbital shifts are measurable via ODMR. PDP offers additional advantages including high sensor doping levels, narrow ODMR linewidths, high contrast, and low-cost single crystal growth. Overall, this work reports low-cost, optically-interrogated PT sensors and lays the foundation for increased versatility of quantum sensors through synthetic molecular design.

Magnetic properties and materials↗
NASA NTRS1996

Method and apparatus for thermographically and quantitatively analyzing a structure for disbonds and/or inclusions

A heat source such as a magnetic induction/eddy current generator remotely heats a region of a surface of a test structure to a desired depth. For example, the frequency of the heating source can be varied to heat to the desired depth. A thermal sensor senses temperature changes in the heated region as a function of time. A computer compares these sensed temperature changes with calibration standards of a similar sample having known disbond and/or inclusion geography(ies) to analyze the test structure. A plurality of sensors can be arranged linearly to sense vector heat flow.

Heyman, Joseph S.↗
NASA NTRS1989

Spacecraft component heater control system

A heater control circuit is disclosed as being constructed in a single integrated circuit, with the integrated circuit conveniently mounted proximate to a spacecraft component requiring temperature control. Redundant heater controllers control power applied to strip heaters disposed to provide heat to a component responsive to sensed temperature from temperature sensors. Signals from these sensors are digitized and compared with a dead band temperature and set point temperature stored in memory to generate an error signal if the sensed temperature is outside the parameter stored in the memory. This error signal is utilized by a microprocessor to selectively instruct the heater controllers to apply power to the strip heaters. If necessary, the spacecraft central processor may access or interrogate the microprocessor in order to alter the set point temperature and dead band temperature range to obtain operational data relating to the operation of an integrated circuit for relaying to the ground control, or to switch off faulty components.

Bachtel, Frederick D.↗
DOE OSTI2021

In Situ Synthesis of Molybdenum Carbide Nanoparticles Incorporated into Laser‐Patterned Nitrogen‐Doped Carbon for Room Temperature VOC Sensing

Abstract Carbon laser‐patterning (CLaP) is emerging as a new tool for the precise and selective synthesis of functional carbon‐based materials for on‐chip applications. The aim of this work is to demonstrate the applicability of laser‐patterned nitrogen‐doped carbon (LP‐NC) for resistive gas‐sensing applications. Films of pre‐carbonized organic nanoparticles on polyethylenetherephthalate are carbonized with a CO 2 ‐laser. Upon laser‐irradiation a compositional and morphological gradient in the films is generated with a carbon content of 92% near the top surface. The specific surface areas of the LP‐NC are increased by introducing sodium iodide (NaI) as a porogen. Electronic conductivity and surface area measurements corroborate the deeper penetration of the laser‐energy into the film in the presence of NaI. Furthermore, impregnation of LP‐NC with MoC 1− x (<10 nm) nanoparticles is achieved by addition of ammonium heptamolybdate into the precursor film. The resulting doping‐sensitive nano‐grain boundaries between p‐type carbon and metallic MoC 1− x lead to an improvement of the volatile organic compounds sensing response of Δ R / R 0 = −3.7% or −0.8% for 1250 ppm acetone or 900 ppm toluene at room temperature, respectively, which is competitive with carbon‐based sensor materials. Further advances in sensitivity and in situ functionalization are expected to make CLaP a useful method for printing selective sensor arrays.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Rare-earth doped thermal barrier coating bond coat for thermally grown oxide luminescence sensing

A thermal barrier coated component, such as a turbine blade formed from a superalloy substrate, includes a thermal barrier coating applied onto the substrate. A metallic bond coat layer is on the substrate and includes rare-earth luminescent dopants. A ceramic top coat layer is on the bond coat layer. A temperature sensing thermally grown oxide (TGO) layer is formed at the interface of the bond coat layer and ceramic top coat layer. The temperature sensing TGO layer includes grown rare-earth luminescent ions migrated from the metallic bond coat layer in an amount sufficient to enable luminescence sensing of the TGO layer for real-time phosphor thermometry temperature measurements at the TGO layer.

Fouliard, Quentin↗