SEARCH · Search NASA

Results for “Engineered barriers”

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.

SourceResearch connectionFrom yearThrough year

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

At least 253 records · Page 14

All sources NASA NTRS DOE OSTI

NASA NTRS1985

Development of thermomechanical life prediction models for thermal barrier coatings

Thermal barrier coatings (TBCs) for turbine airfoils in high-performance engines represent an advanced materials technology with both performance and durability benefits. The foremost TBC benefit is the reduction of heat transferred into air-cooled components. To achieve these benefits, however, the TBC system must be reliable. Mechanistic thermomechanical and thermochemical life models and statistically significant design data are therefore required for the reliable exploitation of TBC benefits on gas turbine airfoils. Garrett's NASA-HOST Program (NAS3-23945) is designed to fulfill these requirements. This program focuses on predicting the lives of two types of strain-tolerant and oxidation-resistant TBC systems that are produced by commercial coating suppliers to the gas turbine industry. The plasma-sprayed TBC system, composed of a low-pressure plasma-spray (LPPS) applied oxidation resistant NiCrAlY bond coating, and an air-plasma-sprayed yttria partially stabilized zirconia insulated layer is applied by both Chromalloy and Klock. The second type of TBC is applied by the electron beam-physical vapor deposition process by Temescal. Thermomechanical life models are being tailored to predict TBC strain tolerance in terms of materials, engine, and mission parameters. Continuum and fracture mechanics approaches and statistical methods are being evaluated to develop tensile and compressive strain functions required to drive a mission analysis capable thermomechanical life model for TBCs. Results of initial testing to calibrate these life models will be presented.

Strangman, T. E.↗

NASA NTRS2004

Depth-Penetrating Measurements Developed for Thermal Barrier Coatings Incorporating Thermographic Phosphors

The insulating properties of thermal barrier coatings (TBCs) provide highly beneficial thermal protection to turbine engine components by reducing the temperature sustained by those components. Therefore, measuring the temperature beneath the TBC is critical for determining whether the TBC is performing its insulating function. Currently, noncontact temperature measurements are performed by infrared pyrometry, which unfortunately measures the TBC surface temperature rather than the temperature of the underlying component. To remedy this problem, the NASA Glenn Research Center, under the Information Rich Test Instrumentation Project, developed a technique to measure the temperature beneath the TBC by incorporating a thin phosphor layer beneath the TBC. By performing fluorescence decay-time measurements on light emission from this phosphor layer, Glenn successfully measured temperatures from the phosphor layer up to 1100 C. This is the first successful demonstration of temperature measurements that penetrate beneath the TBC. Thermographic phosphors have a history of providing noncontact surface temperature measurements. Conventionally, a thermographic phosphor is applied to the material surface and temperature measurements are performed by exciting the phosphor with ultraviolet light and then measuring the temperature-dependent decay time of the phosphor emission at a longer wavelength. The innovative feature of the new approach is to take advantage of the relative transparency of the TBC (composed of yttria-stabilized zirconia) in order to excite and measure the phosphor emission beneath the TBC. The primary obstacle to achieving depth-penetrating temperature measurements is that the TBCs are completely opaque to the ultraviolet light usually employed to excite the phosphor. The strategy that Glenn pursued was to select a thermographic phosphor that could be excited and emit at wavelengths that could be transmitted through the TBC. The phosphor that was selected was yttria doped with europia (Y2O3:Eu), which has a minor excitation peak at 532 nm (green) and an emission peak at 611 nm (red)--both are wavelengths that exhibit significant transmission through the TBC. The measurements were performed on specimens consisting of a 25- m-thick phosphor layer beneath a 100- m-thick TBC. The 532-nm (green) excitation light was provided by a frequency-doubled YAG:Nd (yttrium-aluminum-garnet:neodymium) laser, and the fluorescence decay time measurements were acquired with a modified Raman microscope. The preceding graph compares the intensity of the phosphor emission of the phosphor layer above the TBC versus that of the phosphor layer beneath the TBC. Although there was considerable attenuation of the phosphor signal (a factor of 30), the phosphor emission at the reduced intensity was more than sufficient to perform fluorescence decay time measurements. The following graph shows the fluorescence lifetime temperature dependency for the Y2O3:Eu phosphor layers both above and below the TBC. These curves show an excellent match and indicate that, despite the attenuation due to the overlying TBC, the phosphor layer beneath the TBC still functions as an effective temperature indicator.

Eldridge, Jeffrey I.↗

NASA NTRS2003

Low Thermal Conductivity Thermal Barrier Coatings Developed

Thermal barrier coatings (TBCs) are used extensively in modern gas turbine engines to thermally insulate air-cooled metallic components from the hot gases in the engine. These coatings typically consist of a zirconia-yttria ceramic that has been applied by either plasma spraying or physical vapor deposition. Future engines will rely even more heavily on TBCs and will require materials that have even higher temperature capability with improved insulation (i.e., lower thermal conductivity even after many hours at high temperature). This report discusses new TBCs that have been developed with these future requirements in mind. The Ultra-Efficient Engine Technology Program at the NASA Glenn Research Center is funding this effort, which has been conducted primarily at Glenn with contractor support (GE and Howmet) for physical vapor deposition. As stated, the new TBC not only had to be more insulating but the insulation had to persist even after many hours of exposure-that is, the new TBC had to have both lower conductivity and improved sintering resistance. A new type of test rig was developed for this task. This new test approach used a laser to deliver a known high heat flux in an essentially uniform pattern to the surface of the coating, thereby establishing a realistic thermal gradient across its thickness. This gradient was determined from surface and backside pyrometry; and since the heat flux and coating thickness are known, this permitted continuous monitoring of thermal conductivity. Thus, this laser rig allowed very efficient screening of candidate low-conductivity, sinter-resistant TBCs. The coating-design approach selected for these new low-conductivity TBCs was to identify oxide dopants that had the potential to promote the formation of relatively large and stable groupings of defects known as defect clusters. This approach was used because it was felt that such clusters would reduce conductivity while enhancing stability. The approach proved to be successful: low-conductivity TBCs having improved sintering resistance were developed.

Zhu, Dongming↗

NASA NTRS2007

High Pressure Burner Rig Testing of Advanced Environmental Barrier Coatings for Si3N4 Turbine Components

Advanced thermal and environmental barrier coatings are being developed for Si3N4 components for turbine engine propulsion applications. High pressure burner rig testing was used to evaluate the coating system performance and durability. Test results demonstrated the feasibility and durability of the coating component systems under the simulated engine environments.

Zhu, Dongming↗

NASA NTRS2009

Coated silicon comprising material for protection against environmental corrosion

In accordance with an embodiment of the invention, an article is disclosed. The article comprises a gas turbine engine component substrate comprising a silicon material; and an environmental barrier coating overlying the substrate, wherein the environmental barrier coating comprises cerium oxide, and the cerium oxide reduces formation of silicate glass on the substrate upon exposure to corrodant sulfates.

Hazel, Brian Thomas↗

NASA NTRS2011

Unintended Consequences: How Qualification Constrains Innovation

The development and implementation of new materials and manufacturing processes for aerospace application is often hindered by the high cost and long time span associated with current qualification procedures. The data requirements necessary for material and process qualification are extensive and often require millions of dollars and multiple years to complete. Furthermore, these qualification data can become obsolete for even minor changes to the processing route. This burden is a serious impediment to the pursuit of revolutionary new materials and more affordable processing methods for air vehicle structures. The application of integrated computational materials engineering methods to this problem can help to reduce the barriers to rapid insertion of new materials and processes. By establishing predictive capability for the development of microstructural features in relation to processing and relating this to critical property characteristics, a streamlined approach to qualification is possible. This paper critically examines the advantages and challenges to a modeling-assisted qualification approach for aerospace structural materials. An example of how this approach might apply towards the emerging field of additive manufacturing is discussed in detail.

Brice, Craig A.↗

NASA NTRS2015

Experimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions

NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency of large gas turbine engines. Under ERA the task for a High Pressure Ratio Core Technology program calls for a higher overall pressure ratio of 60 to 70. This mean that the HPC would have to almost double in pressure ratio and keep its high level of efficiency. The challenge is how to match the corrected mass flow rate of the front two supersonic high reaction and high corrected tip speed stages with a total pressure ratio of 3.5. NASA and GE teamed to address this challenge by using the initial geometry of an advanced GE compressor design to meet the requirements of the first 2 stages of the very high pressure ratio core compressor. The rig was configured to run as a 2 stage machine, with Strut and IGV, Rotor 1 and Stator 1 run as independent tests which were then followed by adding the second stage. The goal is to fully understand the stage performances under isolated and multi-stage conditions and fully understand any differences and provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to isolate fluid dynamics loss source mechanisms due to interaction and endwalls. The paper will present the description of the compressor test article, its predicted performance and operability, and the experimental results for both the single stage and two stage configurations. We focus the detailed measurements on 97 and 100 of design speed at 3 vane setting angles.

turbomachinery↗

NASA NTRS2015

Exprimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions.

NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency for large gas turbine engines. Under ERA, the highly loaded core compressor technology program attempts to realize the fuel burn reduction goal by increasing overall pressure ratio of the compressor to increase thermal efficiency of the engine. Study engines with overall pressure ratio of 60 to 70 are now being investigated. This means that the high pressure compressor would have to almost double in pressure ratio while keeping a high level of efficiency. NASA and GE teamed to address this challenge by testing the first two stages of an advanced GE compressor designed to meet the requirements of a very high pressure ratio core compressor. Previous test experience of a compressor which included these front two stages indicated a performance deficit relative to design intent. Therefore, the current rig was designed to run in 1-stage and 2-stage configurations in two separate tests to assess whether the bow shock of the second rotor interacting with the upstream stage contributed to the unpredicted performance deficit, or if the culprit was due to interaction of rotor 1 and stator 1. Thus, the goal was to fully understand the stage 1 performance under isolated and multi-stage conditions, and additionally to provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to understand fluid dynamics loss source mechanisms due to rotor shock interaction and endwall losses. This paper will present the description of the compressor test article and its measured performance and operability, for both the single stage and two stage configurations. We focus the paper on measurements at 97% corrected speed with design intent vane setting angles.

transonic compressors↗

NASA NTRS2015

Experimental and Theoretical Studies of Volatile Metal Hydroxides

Modern superalloys used in the construction of turbomachinery contain a wide range of metals in trace quantities. In addition, metal oxides and silicon dioxide are used to form Thermal Barrier Coatings (TBC) to protect the underlying metal in turbine blades. Formation of volatile hydroxides at elevated temperatures is an important mechanism for corrosion of metal alloys or oxides in combustion environments (N. Jacobson, D. Myers, E. Opila, and E. Copland, J. Phys. Chem. Solids 66, 471-478, 2005). Thermodynamic data is essential to proper design of components of modern gas turbines. It is necessary to first establish the identity of volatile hydroxides formed from the reaction of a given system with high temperature water vapor, and then to determine the equilibrium pressures of the species under operating conditions. Theoretical calculations of reaction energies are an important check of experimental results. This presentation reports results for several important systems: Si-O-H, Cr-O-H, Al-O-H, Ti-O-H, and ongoing studies of Ta-O-H.

Thermal Barrier Coatings↗

NASA NTRS2018

CMC Research at NASA Glenn in 2018: Recent Progress and Plans

As part of NASA's Aeronautics research, Glenn Research Center has developed SiC/SiC Ceramic Matrix Composites for 2700 °F turbine engine applications in the next generation of ultra-efficient aircraft. In this presentation, the development of fiber and matrix constituents and fabrication processes that enabled this advancement will be reviewed, and characterization of the resulting improvements in CMC mechanical properties and durability will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of Ceramic Matrix Composites and Environmental Barrier Coatings will be summarized. Results from current collaborative research with industry and other government agencies will be reviewed. Research plans for 2018 and opportunities for future collaborations with NASA will also be summarized.

Ceramic Matrix Composites↗

NASA NTRS2018

CMC Research at NASA Glenn in 2018: Recent Progress and Plans

Ceramic Matrix Composites↗

NASA NTRS2018

CMC Research at NASA Glenn in 2018: Recent Progress and Plans

As part of NASA's Aeronautics research, Glenn Research Center has developed SiC/SiC Ceramic Matrix Composites for 2700Â°F turbine engine applications in the next generation of ultra-efficient aircraft. In this presentation, the development of fiber and matrix constituents and fabrication processes that enabled this advancement will be reviewed, and characterization of the resulting improvements in CMC mechanical properties and durability will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of Ceramic Matrix Composites and Environmental Barrier Coatings will be summarized. Results from current collaborative research with industry and other government agencies will be reviewed. Research plans for 2018 and opportunities for future collaborations with NASA will also be summarized.

composites↗

NASA NTRS2019

CMC Research at NASA Glenn in 2019: Recent Progress and Plans

As part of NASA's Aeronautics research, Glenn Research Center has developed SiC/SiC Ceramic Matrix Composites (CMC) for 2700 degrees Fahrenheit turbine engine applications in the next generation of ultra-efficient aircraft. In this presentation, the development of fiber and matrix constituents and fabrication processes that enabled this advancement will be reviewed, and characterization of the resulting improvements in CMC mechanical properties and durability will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of Ceramic Matrix Composites and Environmental Barrier Coatings will be summarized. Results from current collaborative research with industry and other government agencies will be reviewed. Research plans for 2019 and opportunities for future collaborations with NASA will also be summarized.

Composites↗

NASA NTRS2020

CMC / EBC Research at NASA Glenn in 2020: Recent Progress and Plans

As part of NASA's Aeronautics research, Glenn Research Center has developed SiC/SiC Ceramic Matrix Composites for 2700°F turbine engine applications in the next generation of ultra-efficient aircraft. In this presentation, the development of fiber and matrix constituents and fabrication processes that enabled this advancement will be reviewed, and characterization of the resulting improvements in CMC mechanical properties and durability will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of Ceramic Matrix Composites and Environmental Barrier Coatings will be summarized. Results from current collaborative research with industry and other government agencies will be reviewed. Research plans for 2020 and opportunities for future collaborations with NASA will also be summarized.

Grady, Joseph E.↗

NASA NTRS2020

CMC / EBC Research at NASA Glenn in 2020: Recent Progress and Plans

As part of NASA's Aeronautics research, Glenn Research Center has developed SiC/SiC Ceramic Matrix Composites for 2700 °F turbine engine applications in the next generation of ultra-efficient aircraft. In this presentation, the development of fiber and matrix constituents and fabrication processes that enabled this advancement will be reviewed, and characterization of the resulting improvements in CMC mechanical properties and durability will be summarized. Progress toward the development and validation of models predicting the effects of the engine environment on durability of Ceramic Matrix Composites and Environmental Barrier Coatings will be summarized. Results from current collaborative research with industry and other government agencies will be reviewed. Research plans for 2020 and opportunities for future collaborations with NASA will also be summarized.

Grady, Joseph↗

NASA NTRS2022

Natural Gas/Oxygen Burner Rig at The NASA Glenn Materials Research Laboratory

This technical memorandum describes the development of a new natural gas/oxygen (NG/O2) fueled burner rig to be used for high-temperature environmental durability studies of advanced materials and components at atmospheric pressure. The burner simulates the high-temperature, high-heat flux, and high-velocity thermal environments encountered in aerospace applications. It will be used to study environmental effects such as water vapor interactions relevant to advanced gas turbine engine materials such as ceramic matrix composites with protective environmental barrier coatings. The highest sample temperature achieved to date in a study of the oxidation and recession of monolithic silicon carbide is 3000 °F.

Burner Rig↗

NASA NTRS2016

NASA Phase2 Unlimited Rights Final Report Research and Technology for Aerospace Propulsion Systems (RTAPS) Task Order: ERA Advanced Core Compressor Technology Program

As part of the NASA Integrated Systems Research Program (ISRP), Environmentally Responsible Aviation (ERA) Project, NASA GRC and GE Aviation have partnered to investigate the technology barriers associated with improved fuel economy of large gas turbine engines. Crucial to improving fuel economy is the increase in pressure ratio (PR) of the core high pressure compressor (HPC). A key enabler to increasing HPC pressure ratios are new technology front stage airfoil designs that have higher efficiency, higher pressure ratios and improvements in front stage part-power operability. The purpose of this work is to design and test two high pressure ratio, high efficiency front block designs. The baseline design, hereafter referred to as Build 1, is similar to what would be found in a high efficiency 30:1 PR class HPC. A redesigned front block with improved blading will also be tested and hereafter be referred to as Build 2. The goal of Build 2 is to increase stage aero loading (increase stage pressure ratio) beyond Build 1 while maintaining equivalent efficiency and stall margin. The detailed inter-stage and traverse data from the two builds will be used to improve understanding of the complex flow physics at high-speed and part-speed conditions that impact performance and operability. By addressing, understanding and solving the challenges associated with aerodynamic losses and stage matching better design strategies can be incorporated in future core compressors with higher efficiency, thereby enabling improvement in mission fuel burn while still meeting operability requirements.

Axial Compressors↗

NASA NTRS2014

ERA Advanced Core Compressor Technology Program

As part of the NASA Integrated Systems Research Program, Environmentally Responsible Aviation Project, NASA GRC and GE Aviation have partnered to investigate the technology barriers associated with improved fuel economy of large gas turbine engines. Crucial to improving fuel economy is the increase in Pressure Ratio (PR) of the core compressor. General Electric is in the process of defining new advanced technology engine concepts and related engine architectures for both commercial and military subsonic and supersonic flight applications. These new concepts and architectures offer the potential of providing substantial improvements in mission fuel burn, emissions, and noise levels relative to SOTA engines and support the needs and goals of future Air force, Navy, and NASA aircraft systems. A key aspect of many of these new engine concepts is an ultra high pressure ratio core compressor. Current SOTA engines such as the GENx utilize a 23:1 class pressure ratio core compressor to achieve an overall pressure ratio in the 50:1 class. Future engines with overall pressure ratios in the 70– 80:1 class will need core compressors with pressure ratios in the 30:1 class. These single spool, ultra high pressure ratio compressors will have inherent challenges. The goal of this work is to provide a dedicated component test vehicle to study the very challenging compressor front stage performance and operability issues that arise in these aggressive machines. With a view to providing highly detailed aerodynamic data that will provide, subject to the rights restrictions for test data afforded under NASA Contract NNC10BA06B/NNC10TA64T, an industry standard data set for CFD validation.

Axial Compressors↗