University Of Tennessee Space Institute Research Articles

Diatomic Line Strengths for Fitting Selected Molecular Transitions of AlO, C2, CN, OH, N2+, NO, and TiO, Spectra

This work communicates line-strength data and associated scripts for the computation and spectroscopic fitting of selected transitions of diatomic molecules. The scripts for data analysis are designed for inclusion in various software packages or program languages. Selected results demonstrate the applicability of the program for data analysis in laser-induced optical breakdown spectroscopy primarily at the University of Tennessee Space Institute, Center for Laser Applications. Representative spectra are calculated and referenced to measured data records. Comparisons of experiment data with predictions from other tabulated diatomic molecular databases confirm the accuracy of the communicated line-strength data.

Surface temperature measurements from a stator vane doublet in a turbine afterburner flame using a YAG:Tm thermographic phosphor

Phosphor thermometry measurements in turbine engine environments can be difficult because of high background radiation levels. To address this challenge, luminescence lifetime-based phosphor thermometry measurements were obtained using thulium-doped Y3Al5O12 (YAG:Tm) to take advantage of the emission wavelengths at 365 nm (1D2 → 3H6 transition) and at 456 nm (1D2 → 3F4 transition). At these wavelengths, turbine engine radiation background is reduced compared with emission from longer wavelength phosphors. Temperature measurements of YAG:Tm coatings were demonstrated using decay of both the 365 and 456 nm emission bands in a furnace environment up to 1400 °C. To demonstrate that reliable surface temperatures based on short-wavelength YAG:Tm emission could be obtained from the surface of an actual engine component in a high gas velocity, highly radiative environment, measurements were obtained from a YAG:Tm-coated Honeywell stator vane doublet placed in the afterburner flame exhaust stream of the augmenter-equipped General Electric J85 turbojet test engine at the University of Tennessee Space Institute (UTSI). Using a probe designed for engine insertion, spot temperature measurements were obtained by measuring luminescence decay times over a range of steady state throttle settings as well as during an engine throttle acceleration. YAG:Tm phosphor thermometry measurements of the stator vane surface in the afterburner exhaust stream using the decay of the 456 nm emission band were successfully obtained at temperatures up to almost 1300 °C. Phosphor thermometry measurements acquired with the engine probe using the decay of the 365 nm emission band were not successful at usefully high temperatures because the probe design allowed transmission of intense unfiltered silica Raman scattering that produced photomultiplier tube saturation with extended recovery times. Recommendations are made for probe modifications that will enable temperature measurements using the 365 nm emission band decay, which will be beneficial in environments with strong reflections of combustor radiation.

Computational Physics Activities at the University of Tennessee Space Institute

A doctoral-level, multidisciplinary class at the University of Tennessee Space Institute teaches computational physics through an innovative blend of physics and engineering experts and activities.

Minimizing Sampling Loss in Trace Gas Emission Measurements for Aircraft Engines by Using a Chemical Quick-Quench Probe

This paper describes the development and testing of a gas sampling probe that quenches chemical reactions by using supersonic expansion and helium dilution. Gas sampling probes are required for accurate measurement of exhaust emissions species, which is critical to determine the performance of an aircraft engine. The probe was designed through rounds of computational modeling and laboratory testing and was subsequently manufactured and then tested at the University of Tennessee Space Institute behind a General Electric J85 turbojet engine at different power settings: idle, maximum military, and afterburning. The experimental test results demonstrated that the chemical quick-quench (CQQ) probe suppressed the oxidation of carbon monoxide (CO) inside the probe system and preserved more CO at afterburning conditions. In addition, the CQQ probe prevented hydrocarbons from being partially oxidized to form CO at idle powers and measured higher hydrocarbons and lower CO emission compared with a conventional probe at that low power condition. The CQQ probe also suppressed nitrogen dioxide (NO2) to nitric oxide (NO) conversion through all engine power settings. These data strongly support the conclusion that the CQQ probe is able to quench unwanted chemical reactions inside the probe for all engine power levels.

Bioenergy and biofuel from biowastes and biomass

This book attempts to provide an in-depth compilation of relevant technical information on several aspects of biofuel and bioenergy production ... it can serve as a useful quick reference for consulting engineers. It is also a good introductory resources for advanced students, researchers, instructors, decision makers, and professionals in the biofuel and bioenergy field. Recommended. —A.C. Sheth, emeritus, University of Tennessee Space Institute, Choice: Current Reviews for Academic Libraries, December 2010.

Unique corrosion and wear resistant identification tags via LISI™ laser marking

A method of marking metal items with unique corrosion and wear resistant identification tags has been developed at the Center for Laser Applications (CLA) at the University of Tennessee Space Institute (UTSI). The method, coined LISI™ laser marking, uses a laser beam to melt a pre-placed powder mix of alloying compounds into the surface of the part in a desired pattern. The formulation of the powder mix is designed to enhance the surface properties of the laser processed areas and protect the identification tags from the specific corrosion and aggressive wear during transportation, operation and overhaul. The specific marking preparation steps, typical processing conditions and a representative set of results are presented for LISI™ laser marking of AISI 4340 steel with Cr-CrB 2, and 2024 aluminum with WC. Results include transverse cross-sectional views and hardness measurements of the marked material, and data on the concentration of alloying compounds within the laser melted layer. The corrosion and wear resistance of LISI™ data matrix marks was also investigated.

Preliminary Economic Analysis of Poultry Litter Gasification Option with a Simple Transportation Model

Several environmental issues are related to the disposal of poultry litter. In an effort to provide a more environmentally friendly alternative than landfill disposal or spreading as a soil amendment, work has been carried out previously at the University of Tennessee Space Institute (UTSI). This past UTSI work was concentrated on developing a catalytic steam gasification concept to produce energy from poultry litter. In the past UTSI studies, preliminary design and economics for a stationary, centralized gasification plant capable of processing ∼100 ton/day of poultry litter were developed. However, in this preliminary design the economic impact of transporting litter to a centralized gasification plant location was not addressed. To determine the preliminary impact of transporting the poultry litter on the overall economics of this energy conversion plant design, a simple transportation model was developed. This model was used in conjunction with the earlier plant design prepared at UTSI to determine the economic feasibility of a centralized, stationary poultry litter gasification plant. To do so, major variables such as traveling distance, plant feed rate (or capacity), fluctuations in the sales price of the product gas (that means value of the energy), population density of poultry farms, impact of tipping fees, and cost of litter were varied. The study showed that for plant with a capacity of 1000 ton/day to be able to withstand several changes in economic conditions and sustain itself, the poultry farm density would need to be ∼0.3 houses/mi2. Smaller plants would need either a higher energy price or some kind of subsidy to be economically feasible.

Economic evaluation of sol–gel based film coating scheme for HTS materials

Under the sponsorship of the US Department of Energy (USDOE), the University of Tennessee Space Institute (UTSI) carried out an engineering evaluation of various options to manufacture long lengths of high-temperature superconductor (HTS) wire/tape. As a result, the leading candidates to apply buffer and/or YBCO (HTS) materials were identified as based on metal organic decomposition (MOD), sol–gel, metal organics chemical vapour deposition (MOCVD) and pulsed laser deposition (PLD). Earlier, Chapman had developed economics for manufacturing schemes based on MOCVD, e-beam and PLD. Using his approach, preliminary economics for a sol–gel based manufacturing scheme has been estimated. In this paper, major findings from our economic evaluation of the sol–gel based film coating scheme are reported.

Statistically designed experimental study of sol–gel-based film coating scheme for high-temperature superconductor and buffer materials and related processing cost evaluation

At the University of Tennessee Space Institute (UTSI), processing factors that influence the epitaxial growth of LaAlO 3 (LAO) on cubic-textured nickel substrates via sol–gel route were investigated using a Taguchi L12 experimental design. Through experimental data collected on omega FWHM, phi FWHM, and composition of orientations, a set of models was generated to characterize the epitaxial growth response to various processing factors. These factors included thermal processing time, temperature, atmosphere, nickel surface roughness, degree of precursor hydrolysis, withdrawal rate, and precursor solution concentration. Based on the results appropriate processing conditions were then identified to produce the greatest degree of epitaxial growth as defined by the non-dimensional term. In addition, preliminary processing cost was developed and compared with the other leading schemes based on methods such as evaporative electron beam, pulsed laser deposition, and metal organics chemical vapor deposition.

KINETICS AND ECONOMICS OF CATALYTIC STEAM GASIFICATION OF BROILER LITTER

In the U.S. in 1996, approximately 7.6 billion broiler chickens were produced. This number has risen continuously over the last few years, with more than 75% of the production coming from the southeastern U.S. Because of the significant growth in broiler production, the amount of litter produced is substantial. Unfortunately, much of the litter is not used properly for fertilizer and ends up polluting rivers and surface waters. Because of decreased availability of land and potential federal regulations, appropriate actions must be taken to find a better way to handle this material. Recently, catalytic steam gasification has been considered as an alternative option to manage broiler litter. The process requires an alkali metal or alkaline earth metal salt and steam to convert the feedstock to a fuel gas consisting primarily of carbon monoxide, carbon dioxide, hydrogen, and methane. The gas may be used as a possible energy source or chemical feedstock. Broiler litter provides a good feedstock for catalytic steam gasification. Litter contains potassium and several other alkali metal salts that can be used as catalyst. If the inherent salts are not sufficient, additional sources, such as naturally occurring langbeinite and potassium carbonate, can be used with minimum additional cost. Broiler litter, with low sulfur content, produces low quantities of unwanted hydrogen sulfide. Moisture present in the wet litter can also provide the steam for gasification, and the solid residue left after gasification can be used as a fertilizer or in cement/concrete manufacturing. Previous bench–scale experiments, at the University of Tennessee Space Institute, (UTSI), showed the technical and economic viability of the steam gasification concept. In the present study, this past work was extended by experimentally determining the optimum conditions for steam gasification as well as by estimating the preliminary economics of a stationary steam gasification system to produce low to medium Btu fuel gas. Results are presented in this article.

High-Temperature Combustion of Pyrolyzed Char Containing Calcium Sulfide

In response to the United States Department of Energy's (U.S. DOE) national research program called “Combustion 2000,” the High Performance Power System (HIPPS) scheme was developed by the Foster Wheeler Development Corporation (FWDC). The HIPPS involved pyrolyzing a high sulfur-containing coal in the presence of limestone sorbent to capture sulfur as CaS and then combusting the resulting char containing spent and unspent sorbent and coal-ash with the fuel gas (mostly CO, H2, and CH4) in a high-temperature furnace called HITAF to drive the steam cycle. To maintain the overall energy efficiency of the HIPPS scheme and to meet the stringent limits on SO2-emissions established in the “Combustion 2000 program, it was necessary to minimize and avoid any SO2-evolution in the HITAF while combusting the CaS-containing pyrolyzed char. To determine the fate of sulfur during combustion of this pyrolyzed char, under a partial support from FWDC, the University of Tennessee Space Institute (UTSI), carried out a small ...

A Fixed Grid Method for Capturing the Motion of Self-Intersecting Wavefronts and Related PDEs

Moving surfaces that self-intersect arise naturally in the geometric optics model of wavefront motion. Standard ray tracing techniques can be used to compute these motions, but they lose resolution as rays diverge. In this paper we develop numerical methods that maintain uniform spatial resolution of the front at all times. Our approach is a fixed grid, wavefront capturing formulation based on the Dynamic Surface Extension method of Steinhoff and Fan (Technical report, University of Tennessee Space Institute). The new methods can treat arbitrarily complicated self intersecting fronts, as well as refraction, reflection, and focusing. We also develop methods for curvature-dependent front motions and the motion of filaments. We validate our methods with numerical experiments.

Bench scale evaluation of batch mode dip-coating of sol-gel LaAlO/sub 3/ buffer material

In a joint program between the University of Tennessee Space Institute (UTSI) and Oak Ridge National Laboratory (ORNL), thin films of lanthanum aluminate (LAO) were formed on [100] strontium titanate (STO) single crystals and on biaxially textured nickel by dip-coating from sol-gel precursors and then annealing. XRD texture measurements were used to evaluate coating parameters including substrate withdrawal speed, degree of hydrolysis, and thermal processing temperature, duration, and atmosphere. LAO films on the order of 1000 thick showed 100% biaxial epitaxy on STO single crystals but only about 50% in-plane epitaxy on nickel. An increase in substrate withdrawal velocity resulted in thicker films. On STO film texture degraded with increased film thickness, but on nickel this effect was not noted, being obscured as a result of the rather poor and variable texture of the nickel substrate used. LAO on STO texture was improved by increases, within the ranges investigated, in the degree of hydrolysis, and in the thermal processing time, temperature, and oxygen concentration. No impediments to production scale-up were found.

99/00730 High performance power system development including scaling considerations

A High-Performance Power System (HIPPS) is being developed under the sponsorship of the United States Department of Energy, Pittsburgh Energy Technology Center (PETC). This system is a coal-fired combined cycle that uses a High Temperature Advanced Furnace (HITAF) to transfer much of the heat to the air- and steam-working fluids. Systems of this type are capable of ovr 47% efficiency (HHV). The Foster Wheeler design uses a pyrolyzation process to convert the coal into fuel gas and char. Having these two fuels available allows the design of a totally coal fueled HIPPS with currently available materials. Foster Wheeler Development corporation (FWDC) is leading a team of companies in the development of this power generation system. The team member companies are AlliedSignal Inc., Bechtel Corporation, Foster Wheeler Energy Corporation, University of Tennessee Space Institute and Westinghouse Electric Corporation. Massachusetts Institute of Technology (MIT) and Cornell University are working on a separately funded DOE project titled The Scale-Up of Large Pressurized Fluidized Beds for Advanced Coal-Fired power processes. The work being done in this project will be used to support the scale up of results from the pyrolyzer testing.

98/00518 Characteristics of char combustion in a high temperature advanced furnace for the high performance power system

A high performance power system (HIPPS) with a thermal-to-electric conversion efficiency of more than 47% is being developed by Foster Wheeler Development Corporation under the sponsorship of the United States Department of Energy-Pittsburgh Energy Technology Center. This system is a coal-fired combined cycle system that employs a high temperature advanced furnace (HITAF) to transfer the heat to the air and steam working fluids. In the HIPPS plant, pulverized coal and sorbent are fed into the pyrolyzer where the coal is partially gasified to produce a low-Btu fuel gas and combustible char. The fuel gas is supplied to the gas turbine combustor and the char is burned in the HITAF. This paper examines char combustion in the HITAF. It presents laboratory characterization of char combustion and numerical simulation of char combustion in a sub-scale test combustor. The laboratory characterization tests are conducted to determine the char ignition index, relative fuel reactivity, and drop-tube furnace performance. Sub-scale furnace tests are planned at Foster Wheeler`s Combustion and Environmental Test Facility (CETF) and University of Tennessee Space Institute`s combustion test facility, the firing rate at both facilities being 10 MW{sub t} (35 MMBtu/hr). Numerical simulation of char combustion at the Foster Wheeler CETF ismore » performed using a state-of-the-art furnace combustion computational fluid dynamics (CFD) code. The CFD modeling of furnace char combustion is a three-dimensional Eulerian representation of turbulent reacting gas flow with a Lagrangian simulation of char particle conservation equations. Char particles interact with the continuum gas flow field via mass, momentum and energy exchanges. Radiative heat transfer and pollutant formation mechanisms are included in the CFD model. The results of the laboratory bench-scale tests to characterize the char and CFD simulation of a sub-scale test combustor are detailed in the paper.« less

Destruction of Low Levels of Volatile Organic Compounds in Dry Air Streams by an Electron-Beam Generated Plasma

The destruction of parts per million (ppm) levels of volatile organic compounds in a dry air stream by high–energy electron–beam irradiation has been investigated in a pilot plant at the University of Tennessee Space Institute, Tullahoma, Tennessee. In a series of experiments, dry air contaminated with various VOCs in the concentration range of 50–1000 ppm were treated in the UTSI pilot plant to determine the extent of destruction at various electronbeam dose levels. The destruction removal efficiency was determined as a function of the electron beam irradiation dose. The results suggest a charge transfer reaction as the major decomposition mechanism. A theoretical foundation of the process, along with a simple first–generation reaction kinetics model, a summary of the results from the pilot plant flow reactor, and a preliminary cost analysis for a fullscale detoxification plant using currently available electronbeam gun technology are presented in this paper.

Anion-Exchange Resin-Based Desulfurization and Dechlorination of Spent Sorbent Material

Emissions of acid gases such as SO{sub 2} and HCl/Cl{sub 2} from energy conversion or waste incineration facilities are unacceptable. Alkali metal sorbents can remove these acid gases more efficiently than the lime/limestone type sorbents used in the conventional flue gas desulfurization (FGD) systems. It is desirable that the spent sorbent materials obtained from such emissions control systems be converted to sulfur- and chlorine-free forms, so that they can be reused. The weak-base, anion-exchange resin-based desulfurization concept, developed and tested at the University of Tennessee Space Institute (UTSI), can also simultaneously remove sulfur- and chlorine-containing species from such spent sorbent materials. Under the U.5. Department of Energy`s (DOE) sponsorship, bench scale studies have been carried out to evaluate the feasibility of removing sulfur- and chlorine-containing species using this resin-based concept. Preliminary cost estimates for a regeneration scheme employing reactivated alkali metal-based spent sorbent material using the ion-exchange resin-based concept seem attractive and comparable to currently available options. 22 refs., 6 figs., 10 tabs.

Integration architecture of expert systems, neural networks, hypertext, and multimedia can provide competitive opportunities for industrial applications

Abstract This paper promotes the idea of integration of computer software technologies; such as, expert systems, neural networks, hypertext, multimedia, and graphics user interface (GUI), to an unique hybrid system that increase market opportunities and competitiveness. The goal is to present ingredients of a business strategy that can ensure the capability to provide long-term competitiveness for industrial applications. Concepts for development integration and flexibility, prototype system transferring, teaming, and other consideration for winning, evolving at The University of Tennessee Space Institute (UTSI) and the Center for Space and Applied Research (CSTAR), are presented to amplify on salient aspects of competitiveness.

Velocity limiting magnetohydrodynamic effects in railgun plasma armatures

The results of a four-year theoretical and experimental research program in railgun armature physics at the University of Tennessee Space Institute are reviewed with an emphasis on understanding how the magnetohydrodynamic (MHD) flowfield and electromagnetic interactions limit the velocity in plasma and hybrid armature railguns. The understanding of the 3D plasma armature flowfield has been developed through a combination of highly instrumented railgun experiments, secondary arc performance models, and 2D MHD calculations. These 2D calculations are only qualitative in nature, but they provide insight into the complex armature flow and indicate that the formation of secondary armatures, ablation drag, and primary armature preparation are interrelated. Experimental evidence suggests that 3D MHD flow effects are very important in controlling these phenomena. >

Improved Version of Anion-exchange Resin-based Desulfurization Process for Alkali Metal Sulfates

At The University of Tennessee Space Institute (UTSI), a low-temperature low-cost sorbent/seed regeneration scheme has been developed and tested at the bench scale level in which commercially available weak base, anion-exchange resins are used to remove soluble sulfate ions from aqueous solutions containing alkali metal sulfates. The earlier UTSI scheme has now been improved and simplified further by carrying out the resin exhaustion and carbonation steps simultaneously under moderate CO 2 pressure