Search NASA⌕ Search

Engineering topics

Alvin, Mary Anne

Publications and source records attributed to Alvin, Mary Anne.

11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Method of making an apparatus for transpiration cooling of substrates such as turbine airfoils

A method and apparatus for generating transpiration cooling using an oxidized porous HTA layer metallurgically bonded to a substrate having micro-channel architectures. The method and apparatus generates a porous HTA layer by spreading generally spherical HTA powder particles on a substrate, partially sintering under O.sub.2 vacuum until the porous HTA layer exhibits a porosity between 20% and 50% and a neck size ratio between 0.1 and 0.5, followed by a controlled oxidation generating an oxidation layer of alumina, chromia, or silica at a thickness of about 20 to about 500 nm. In particular embodiments, the oxidized porous HTA layer and the substrate comprise Ni as a majority element. In other embodiments, the oxidized porous HTA layer and the substrate further comprise Al, and in additional embodiments, the oxidized porous HTA layer and the substrate comprise .gamma.-Ni+.gamma.'-Ni.sub.3Al.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Characterization and Recovery of Rare Earths from Coal and By-Products [Poster]

Roughly 87% of REEs came from China in 2014. There is a potential national security and supply risk for critical rare earths for defense and clean energy: Y, Nd, Eu, Dy, Tb. They are not typically found in concentrated ores and are difficult to extract and separate. Because REs are not distributed evenly, there is an excess supply for some REs and shortages for other REs. Much of the recent research on coal utilization in the United States has focused upon the capture of pollutants such as acid gases, particulates, and mercury, and the greenhouse gas carbon dioxide. The possible recovery of rare earth elements from abundant coal and byproducts is an exciting new research area, representing a dramatic paradigm shift for coal. Additional data is needed on the rare earth contents of coals and byproducts in order to determine the most promising potential feed materials for extraction processes. Future work will likely focus on the characterization of coals and byproducts, as well as separation methods for rare earth recovery.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Characterization and Recovery of Rare Earths from Coal and By-Products

Coal is a precious resource, both in the United States and around the world. The United States has a 250-year supply of coal, and generates between 30 - 40% of its electricity through coal combustion. Approximately 1 Gt of coal has been mined annually in the US, although the 2015 total will likely be closer to 900 Mt (http://www.eia.gov/coal/production/quarterly/). Most of the coal is burned for power generation, but substantial quantities are also employed in the manufacture of steel, chemicals, and activated carbons. Coal has a positive impact upon many industries, including mining, power, rail transportation, manufacturing, chemical, steel, activated carbon, and fuels. Everything that is in the earth’s crust is also present within coal to some extent, and the challenge is always to utilize abundant domestic coal in clean and environmentally friendly manners. In the case of the rare earths, these valuable and extraordinarily useful elements are present within the abundant coal and coal by-products produced domestically and world-wide. These materials include the coals, as well as the combustion by-products such as ashes, coal preparation wastes, gasification slags, and mining by-products. All of these materials can be viewed as potential sources of rare earth elements. Most of the common inorganic lanthanide compounds, such as the phosphates found in coal, have very high melting, boiling, and thermal decomposition temperatures, allowing them to concentrate in combustion and gasification by-products. Furthermore, rare earths have been found in interesting concentrations in the strata above and below certain coal seams. Much of the recent research on coal utilization in the United States has focused upon the capture of pollutants such as acid gases, particulates, and mercury, and the greenhouse gas carbon dioxide. The possible recovery of rare earth and other critical elements from abundant coal and by-products is an exciting new research area, representing a dramatic paradigm shift for coal.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

Method of producing an oxide dispersion strengthened coating and micro-channels

The disclosure provides a method for the production of composite particles utilizing a mechano chemical bonding process following by high energy ball milling on a powder mixture comprised of coating particles, first host particles, and second host particles. The composite particles formed have a grain size of less than one micron with grains generally characterized by a uniformly dispersed coating material and a mix of first material and second material intermetallics. The method disclosed is particularly useful for the fabrication of oxide dispersion strengthened coatings, for example using a powder mixture comprised of Y.sub.2O.sub.3, Cr, Ni, and Al. This particular powder mixture may be subjected to the MCB process for a period generally less than one hour following by high energy ball milling for a period as short as 2 hours. After application by cold spraying, the composite particles may be heat treated to generate an oxide-dispersion strengthened coating.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Turbine Thermal Management (Annual Report)

The FY13 NETL-RUA Turbine Thermal Management effort supported the Department of Energy’s (DOE) Hydrogen Turbine Program through conduct of novel, fundamental, basic, and applied research in the areas of aerothermal heat transfer, coatings development, and secondary flow control. This research project utilized the extensive expertise and facilities readily available at NETL and the participating universities. The research approach included explorative studies based on scaled models and prototype coupon tests conducted under realistic high-temperature, pressurized, turbine operating conditions.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2012

Ultrasonic Detection of Delamination and Material Characterization of Thermal Barrier Coatings

This article describes ultrasonic nondestructive evaluation (NDE) to detect the changes of material properties and provide early warning of delamination in thermal barrier coating (TBC) systems. NDE tests were performed on single-crystal René N5 superalloy coupons that were coated with a commercially available MCrAlY bond coat and an air plasma sprayed 7% yttria-stabilized zirconia (YSZ) top coat deposited by Air Plasma Spray method, as well as Haynes 230 superalloy coupons coated with MCrA1Y bond coat, and an electron beam physical vapor deposit of 7% YSZ top coat. The TBC coupons were subjected to either cyclic or isothermal exposure for various lengths of time at temperatures ranging from 900 to 1100 °C. The ultrasonic measurements performed on the coupons had provided an early warning of delamination along the top coat/TGO interface before exposure time, when delamination occurred. The material's property (Young’s modulus) of the top coat was estimated using the measured wave speeds. Finite element analysis (FEA) of the ultrasonic wave propagation was conducted on a simplified TBC system to verify experimental observations. The technique developed was also demonstrated on an as-manufactured turbine blade to estimate normalized top coat thickness measurements.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Effects of Pin Detached Space on Heat Transfer in a Rib Roughened Channel

An experimental study is performed to investigate the heat transfer characteristics and frictional losses in a rib roughened channel combined with detached pin-fins. The overall channel geometry (W=76.2 mm, E=25.4 mm) simulates an internal cooling passage of wide aspect ratio (3:1) in a gas turbine airfoil. With a given pin diameter, D=6.35 mm=[1/4]E, three different pin-fin height-to-diameter ratios, H/D=4, 3, and 2, were examined. Each of these three cases corresponds to a specific pin array geometry of detachment spacing (C) between the pin-tip and one of the endwalls, i.e., C/O=0, 1, 2, respectively. The rib height-to-channel height ratio is 0.0625. Two newly proposed cross ribs, namely the broken rib and full rib are evaluated in this effort. The broken ribs are positioned in between two consecutive rows of pin-fins, while the full ribs are fully extended adjacent to the pin-fins. The Reynolds number, based on the hydraulic diameter of the unobstructed cross section and the mean bulk velocity, ranges from 10,000 to 25,000. The experiment employs a hybrid technique based on transient liquid crystal imaging to obtain distributions of the local heat transfer coefficient over all of the participating surfaces, including the endwalls and all pin elements. The presence of ribs enhances local heat transfer coefficient on the endwall substantially by approximately 20% to 50% as compared to the neighboring endwall. In addition, affected by the rib geometry, which is a relatively low profile as compared to the overall height of the channel, the pressure loss seems to be insensitive to the presence of the ribs. However, from the overall heat transfer enhancement standpoint, the baseline cases (without ribs) outperform cases with broken ribs or full ribs.

42 ENGINEERING↗
DOE OSTI2012

Annual Report: Turbines

The FY12 NETL-RUA Turbine Thermal Management effort supported the Department of Energy (DOE) Hydrogen Turbine Program through conduct of novel, fundamental, basic, and applied research in the areas of aerothermal heat transfer, coatings development, and secondary flow control. This research project utilized the extensive expertise and facilities readily available at NETL and the participating universities. The research approach includes explorative studies based on scaled models and prototype coupon tests conducted under realistic high-temperature, pressurized, turbine operating conditions. This research is expected to render measurable outcomes that will meet DOE advanced turbine development goals of a 3- to 5-point increase in power island efficiency and a 30 percent power increase above the hydrogen-fired combined cycle baseline. In addition, knowledge gained from this project will further advance the aerothermal cooling and TBC technologies in the general turbine community. This project has been structured to address Development and design of aerothermal and materials concepts in FY12-13. Design and manufacturing of these advanced concepts in FY13. Bench-scale/proof-of-concept testing of these concepts in FY13-14 and beyond. The Turbine Thermal Management project consists of four tasks that focus on a critical technology development in the areas of aerothermal and heat transfer, coatings and materials development, design integration and testing, and a secondary flow rotating rig.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2012

Effects of Pin Detached Space on Heat Transfer and Pin-Fin Arrays

Heat transfer and pressure characteristics in a rectangular channel with pin-fin arrays of partial detachment from one of the endwalls have been experimentally studied. The overall channel geometry (W=76.2 mm, E=25.4 mm) simulates an internal cooling passage of wide aspect ratio (3:1) in a gas turbine airfoil. With a given pin diameter, D=6.35 mm=¼E, three different pin-fin height-to-diameter ratios, H/D=4, 3, and 2, were examined. Each of these three cases corresponds to a specific pin array geometry of detachment spacing (C) between the pin tip and one of the endwalls, i.e., C/D=0, 1, 2, respectively. The Reynolds number, based on the hydraulic diameter of the unobstructed cross-section and the mean bulk velocity, ranges from 10,000 to 25,000. The experiment employs a hybrid technique based on transient liquid crystal imaging to obtain the distributions of the local heat transfer coefficient over all of the participating surfaces, including the endwalls and all the pin elements. Experimental results reveal that the presence of a detached space between the pin tip and the endwall has a significant effect on the convective heat transfer and pressure loss in the channel. The presence of pin-to-endwall spacing promotes wall-flow interaction, generates additional separated shear layers, and augments turbulent transport. In general, an increase in detached spacing, or C/D, leads to lower heat transfer enhancement and pressure drop. However, C/D=1, i.e., H/D=3, of a staggered array configuration exhibits the highest heat transfer enhancement, followed by the cases of C/D=0 and C/D=2, i.e., H/D=4 or 2, respectively.

42 ENGINEERING↗
NASA NTRS2010

Two stage catalytic combustor

A catalytic combustor (14) includes a first catalytic stage (30), a second catalytic stage (40), and an oxidation completion stage (49). The first catalytic stage receives an oxidizer (e.g., 20) and a fuel (26) and discharges a partially oxidized fuel/oxidizer mixture (36). The second catalytic stage receives the partially oxidized fuel/oxidizer mixture and further oxidizes the mixture. The second catalytic stage may include a passageway (47) for conducting a bypass portion (46) of the mixture past a catalyst (e.g., 41) disposed therein. The second catalytic stage may have an outlet temperature elevated sufficiently to complete oxidation of the mixture without using a separate ignition source. The oxidation completion stage is disposed downstream of the second catalytic stage and may recombine the bypass portion with a catalyst exposed portion (48) of the mixture and complete oxidation of the mixture. The second catalytic stage may also include a reticulated foam support (50), a honeycomb support, a tube support or a plate support.

Alvin, Mary Anne↗