Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “HIGH TEMPERATURE ENVIRONMENT”

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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Development of Temperature Compensation Tools for SPNDs Operating in High Temperature Environments

Two rhodium-based self-powered neutron detectors (Rh-SPNDs) were irradiated at the Massachusetts Institute of Technology Reactor as a follow-on experiment to the heated irradiation previously conducted at the Neutron Radiography facility at Idaho National Laboratory. The experiment was conducted over the temperature ranges of 600-850°C to further examine the effects of temperature on the Rh-SPNDs. Four tests of varying temperature and power were performed. The tests identified two types of temperature effects consistent with historical evaluations. One effect is a prompt proportionality to temperature at steady-state reactor power due to the decrease in Rh-SPND insulation resistance. The other effect is a delayed effect generated from displacement currents generated by changing the space charge within the insulator as a function of temperature. The result of this experiment demonstrates a characterizable responses to temperature that is feasible for developing a temperature compensation tool for SPND operating in high temperatures. The characteristics identified in this experiment will be integrated within the delayed-response compensation techniques for FY23 evaluation.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1974

A study of the diffusional behavior of a two-phase metal matrix composite exposed to a high temperature environment

The progress of diffusion-controlled filament-matrix interaction in a metal matrix composite where the filaments and matrix comprise a two-phase binary alloy system was studied by mathematically modeling compositional changes resulting from prolonged elevated temperature exposure. The analysis treats a finite, diffusion-controlled, two-phase moving-interface problem by means of a variable-grid finite-difference technique. The Ni-W system was selected as an example system. Modeling was carried out for the 1000 to 1200 C temperature range for unidirectional composites containing from 6 to 40 volume percent tungsten filaments in a Ni matrix. The results are displayed to show both the change in filament diameter and matrix composition as a function of exposure time. Compositional profiles produced between first and second nearest neighbor filaments were calculated by superposition of finite-difference solutions of the diffusion equations.

Tenney, D. R.↗
NASA NTRS2005

Hydrothermal Vent Sampler: Does Life Exist in High Temperature Environments?

The main purpose of this research is to search for the existence of biomass under extreme temperature and pressure conditions to determine the upper bounds of environments on which life can exist. Vents are, simply put, underwater volcano openings located at the bottom of the sea. The conditions at these locations are considerably extreme with pressures of up to 10,000 psi, and enormous temperature gradients. The temperature of the water near these vents is around 400 C, while that of the surrounding water is about 3 C. The extremity of these conditions makes it hard to estimate the existence of life in those environments. I n order to find whether such existence happens, we need to search for biomass inside these vents. The vent sampler is a device that has the purpose of safely and accurately collecting this biomass for examination. This sampler is constituted of a Series of filters of the order of 100-0.2 microns in size. Since this is a 3-year project, it has not concluded yet; however, during the time I contributed to this project, I worked with the mechanical design of this sampler device including the selection, assembly, and testing of the various subsystems and the design and construction of the electronics enclosure.

Rivadeneyra, Cesar R.↗
NASA NTRS2000

Composite fastener for use in high temperature environments

A fastener includes a composite body and a metal coupling attached to the body. The metal coupling includes an attachment structure to connect the fastener to an external structure. An assembly of components includes a first metallic component having a first coefficient of thermal expansion, a second non-metallic component having a second coefficient of thermal expansion different from the first thermal expansion and having a groove that receives a fastener that extends between the groove and the second component, the fastener slidably engaging the groove to accommodate relative expansion between the components.

Miller, Robert J.↗
NASA NTRS2017

Fiber Optic Temperature Sensor Insert for High Temperature Environments

A thermal protection system (TPS) test plug has optical fibers with FBGs embedded in the optical fiber arranged in a helix, an axial fiber, and a combination of the two. Optionally, one of the optical fibers is a sapphire FBG for measurement of the highest temperatures in the TPS plug. The test plug may include an ablating surface and a non-ablating surface, with an engagement surface with threads formed, the threads having a groove for placement of the optical fiber. The test plug may also include an optical connector positioned at the non-ablating surface for protection of the optical fiber during insertion and removal.

Black, Richard James↗
NASA NTRS2014

Development and Performance Verification of Fiber Optic Temperature Sensors in High Temperature Engine Environments

A High Temperature Fiber Optic Sensor (HTFOS) has been developed at NASA Glenn Research Center for aircraft engine applications. After fabrication and preliminary in-house performance evaluation, the HTFOS was tested in an engine environment at NASA Armstrong Flight Research Center. The engine tests enabled the performance of the HTFOS in real engine environments to be evaluated along with the ability of the sensor to respond to changes in the engine's operating condition. Data were collected prior, during, and after each test in order to observe the change in temperature from ambient to each of the various test point levels. An adequate amount of data was collected and analyzed to satisfy the research team that HTFOS operates properly while the engine was running. Temperature measurements made by HTFOS while the engine was running agreed with those anticipated.

Adamovsky, Grigory↗
NASA NTRSDate not supplied

Electrical and Dielectric Characterizations of HTCC Electronic Packages for High Temperature Harsh Environment Applications

A prototype high temperature co-fired ceramic (HTCC) alumina packaging system composed of a 32-I/Os package and a compatible circuit board was previously developed and demonstrated for long term operation in 500 °C environments. The electrical / dielectric parasitic parameters of that chip level package were characterized and reported. This co-fired packaging system with platinum (Pt) conductor has successfully facilitated tests of silicon carbide (SiC) analog and digital integrated circuits (ICs) developed at NASA GRC at 500°C for up to 10,000 hours in ambient oven environment and 60 earth days in Venus surface environment with simulated temperature, pressure, and chemical constituents. Based on these previous results, this paper introduces new designs of Pt-HTCC packages with 16, 24, and 44 I/Os for packaging a new generation SiC ICs with 8, 24, 56, 62, and 72 I/Os to be tested in high temperature harsh environments. The package with 44 I/Os is specifically designed for the new SiC ICs with 56, 62, and 72-I/Os and electrical connection needs, the power pads of this package are consolidated, and an array of I/O pads distributed on separated vertical levels (inside the package) is used to control the overall package dimensions and mitigate the parasitic effects at high temperatures. This paper will present the detailed design of these chip-level packages and results of electrical and dielectric characterization of these newly fabricated chip-level Pt-HTCC packages.

High temperature↗
NASA NTRSDate not supplied

Electrical and Dielectric Characterizations of HTCC Electronic Packages for High Temperature Harsh Environment Applications

A prototype high temperature co-fired ceramic (HTCC) alumina packaging system composed of a 32-I/Os package and a compatible circuit board was previously developed and demonstrated for long term operation in 500 °C environments. The electrical / dielectric parasitic parameters of that chip level package were characterized and reported. This co-fired packaging system with platinum (Pt) conductor has successfully facilitated tests of silicon carbide (SiC) analog and digital integrated circuits (ICs) developed at NASA GRC at 500°C for up to 10,000 hours in ambient oven environment and 60 earth days in Venus surface environment with simulated temperature, pressure, and chemical constituents. Based on these previous results, this paper introduces new designs of Pt-HTCC packages with 16, 24, and 44 I/Os for packaging a new generation SiC ICs with 8, 24, 56, 62, and 72 I/Os to be tested in high temperature harsh environments. The package with 44 I/Os is specifically designed for the new SiC ICs with 56, 62, and 72-I/Os and electrical connection needs, the power pads of this package are consolidated, and an array of I/O pads distributed on separated vertical levels (inside the package) is used to control the overall package dimensions and mitigate the parasitic effects at high temperatures. This paper will present the detailed design of these chip-level packages and results of electrical and dielectric characterization of these newly fabricated chip-level Pt-HTCC packages.

High temperature↗
NASA NTRS1991

Thin coatings for protecting titanium aluminides in high-temperature oxidizing environments

Titanium aluminides have high specific strengths at high temperatures but are susceptible to environmental attack. Their use in many aerospace applications would require that they be protected with coatings that, for structural efficiency, must be thin. It is conceivable that acceptable coatings might be found in several oxide systems, and consequently, oxide coatings of many compositions were prepared from sol-gels for study. Response-surface methodology was used to refine coating compositions and factorial experiments were used to develop coating strategies. Oxygen permeability diagrams of two-layer coatings for several oxide systems, an analysis of multiple-layer coatings on rough and polished surfaces, and modeling of the oxidation weight gain are presented.

Wiedemann, K. E.↗
NASA NTRS1997

High-Temperature Passive Power Electronics

In many future NASA missions - such as deep-space exploration, the National AeroSpace Plane, minisatellites, integrated engine electronics, and ion or arcjet thrusters - high-power electrical components and systems must operate reliably and efficiently in high-temperature environments. The high-temperature power electronics program at the NASA Lewis Research Center focuses on dielectric and insulating material research, the development and characterization of high-temperature components, and the integration of the developed components into a demonstrable 200 C power system - such as an inverter. NASA Lewis has developed high-temperature power components through collaborative efforts with the Air Force Wright Laboratory, Northrop Grumman, and the University of Wisconsin. Ceramic and film capacitors, molypermalloy powder inductors, and a coaxially wound transformer were designed, developed, and evaluated for high-temperature operation.

Source record↗
DOE OSTI2024

Mechanical degradation of duplex SiC-fiber reinforced SiC matrix composite tubes under a controlled high-temperature steam environment

This paper describes results from the mechanical evaluation of unirradiated SiC fiber–reinforced SiC matrix composite tubes under a controlled high-temperature steam environment. The experiments were aimed at identifying key material degradation behavior under environments relevant to loss-of-coolant accidents of light water reactors. Mechanical tests of the SiC composite tubes at 1000 °C under steam and inert environments were conducted using a unique test capability. Further, the material tested was a duplex tube with a thick monolithic SiC layer on the outer surface. The tubes were subjected to preloading at ~100 MPa in tension before exposure to high-temperature steam with up to 75% of the preload at a constant displacement. In the presence of matrix cracks, the steam exposure caused embrittlement of the SiC composite tubes and failure at a stress level below the pretest stress. The material degradation was explained by a fiber oxidation model, which can be applied to various SiC cladding concepts. The embrittlement could be a limiting factor for using SiC cladding subjected to loss-of-coolant accident conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Quantifying the effects of varietal types × management on the spatial variability of sorghum biomass across US environments

Abstract Regional‐scale estimations of sorghum biomass production allow identification of optimum genotype×environment×management (G×E×M) combinations for bioenergy generation. The objective of this study was to determine the degree of contributions of G, E, and M toward variability in sorghum biomass in the United States. Using the Agricultural Production Systems sIMulator in a grid computing platform, biomass was simulated for irrigated and rainfed conditions for 30 years across the United States for four sorghum varietal types (grain—GS, sudangrass—SS, photosensitive—PS, and photo‐insensitive—PI). Simulated biomass was assessed by environments clustered using the sum of intercepted solar radiation ( ir ), mean of temperature stress factor ( tp ) and water stress factor ( sw ). Simulated biomass ranged from 5.8 t ha −1 (GS‐rainfed) to 27.5 t ha −1 (PI‐irrigated). Under high‐temperature environments (mean annual temperature = 25°C), rainfed biomass between 40 and 80 days after planting (DAP) was strongly correlated with sw ( r = 0.64–0.86) and irrigated biomass with ir ( r = 0.68–0.81). Under low‐temperature environments (mean annual temperature = 18°C) after 40 DAP, tp and ir had greater effects than sw ( r = 0.55–0.82). Biomass variance was mainly explained by varietal type (50%–76%) in all environments×irrigation combinations, except in the high‐ and mid‐temperature environments under rainfed conditions where rainfall had the major effect (25%–45%). However, when mean temperature during the growing season decreased from 25°C (high environments) to 18°C (low environments), the contribution of mean temperature to biomass variance increased from 7% to 34% (rainfed) and from 4% to 36% (irrigated). Varietal type had the larger interactions with other factors independently of the environment and irrigation. We demonstrated a need to quantify (i) the main G×E×M drivers of biomass variability based on environmental stress factors and (ii) the variance contribution of these drivers on sorghum biomass. Our regional‐scale estimations are key inputs for future robust biomass projections of energy sorghum genotypes integrating G×E×M under climate change scenarios.

Ojeda, Jonathan J.↗