Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation (open access)

Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation

While numerous techniques exist for remediation of contaminant plumes in groundwater or near the soil surface, remediation methods in the deep vadose zone are less established due to complex transport dynamics and sparse microbial populations. There is a lack of knowledge on how physical and hydrologic features of the vadose zone control microbial growth and colonization in response to nutrient delivery during bioremediation. Yet pollution in the vadose zone poses a serious threat to the groundwater resources lying deeper in the sediment. While the contaminants may be slowly degraded by native microbial communities, microbial degradation rates rarely keep pace with the spread of the pollutant. It is crucial to increase indigenous microbial degradation in the vadose zone to combat groundwater contamination.
Date: January 26, 2004
Creator: Brokman, Fred; Selker, John & Rockhold, Mark
Object Type: Report
System: The UNT Digital Library
Recent results from CDF (open access)

Recent results from CDF

The authors report on the recent heavy-quark results from CDF in Run IIa. They focus on a selection of mature analyses that demonstrate the capabilities of the experiment to extract interesting physics from the data. A few of the results presented have already been submitted for publication and papers are being prepared for most of the others.
Date: January 26, 2004
Creator: Harr, R.
Object Type: Article
System: The UNT Digital Library
Fast Neutral Pressure Gauges in NSTX (open access)

Fast Neutral Pressure Gauges in NSTX

Successful operation in NSTX of two prototype fast-response micro ionization gauges during plasma operations has motivated us to install five gauges at different toroidal and poloidal locations to measure the edge neutral pressure and its dependence on the type of discharge (L-mode, H-mode, CHI) and the fueling method and location. The edge neutral pressure is also used as an input to the transport analysis codes TRANSP and DEGAS-2. The modified PDX-type Penning gauges are well suited for pressure measurements in the NSTX divertor where the toroidal field is relatively high. Behind the NSTX outer divertor plates where the field is lower, an unshielded fast ion gauge of a new design has been installed. This gauge was developed after laboratory testing of several different designs in a vacuum chamber with applied magnetic fields.
Date: April 26, 2004
Creator: Raman, R.; Kugel, H. W.; Gernhardt, R.; Provost, T.; Jarboe, T. R. & Soukhanovskii, V.
Object Type: Report
System: The UNT Digital Library
A first-generation prototype dynamic residential window (open access)

A first-generation prototype dynamic residential window

We present the concept for a ''smart'' highly efficient dynamic window that maximizes solar heat gain during the heating season and minimizes solar heat gain during the cooling season in residential buildings. We describe a prototype dynamic window that relies on an internal shade, which deploys automatically in response to solar radiation and temperature. This prototype was built at Lawrence Berkeley National Laboratory from commercially available ''off-the-shelf'' components. It is a stand-alone, standard-size product, so it can be easily installed in place of standard window products. Our design shows promise for near-term commercialization. Improving thermal performance of this prototype by incorporating commercially available highly efficient glazing technologies could result in the first window that could be suitable for use in zero-energy homes. The unit's predictable deployment of shading could help capture energy savings that are not possible with manual shading. Installation of dynamically shaded windows in the field will allow researchers to better quantify the energy effects of shades, which could lead to increased efficiency in the sizing of heating, ventilation, and air conditioning equipment for residences.
Date: October 26, 2004
Creator: Kohler, Christian; Goudey, Howdy & Arasteh, Dariush
Object Type: Report
System: The UNT Digital Library
A Novel Membrane Reactor for Direct Hydrogen Production From Coal Annual Report (open access)

A Novel Membrane Reactor for Direct Hydrogen Production From Coal Annual Report

Gas Technology Institute is developing a novel concept of membrane gasifier for high efficiency, clean and low cost production of hydrogen from coal. The concept incorporates a hydrogen-selective membrane within a gasification reactor for direct extraction of hydrogen from coal-derived synthesis gases. The objective of this project is to determine the technical and economic feasibility of this concept by screening, testing and identifying potential candidate membranes under high temperature, high pressure, and harsh environments of the coal gasification conditions. The best performing membranes will be selected for preliminary reactor design and cost estimates. To evaluate the performances of the candidate membranes under the gasification conditions, a high temperature/high pressure hydrogen permeation unit has been constructed in this project. The unit is designed to operate at temperatures up to 1100 C and pressures to 60 atm for evaluation of ceramic membranes such as mixed ionic conducting membrane. The unit was fully commissioned and is operational. Several perovskite membranes based on the formulations of BCN (BaCe{sub 0.8}Nd{sub 0.2}O{sub 3-x}) and BCY (BaCe{sub 0.8}Y{sub 0.2}O{sub 3-x}) were prepared by GTI and tested in the new permeation unit. These membranes were fabricated by either uniaxial pressing or tape casting technique with thickness ranging from …
Date: October 26, 2004
Creator: Doong, Shain; Ong, Estela; Atroshenko, Mike; Lau, Francis & Roberts, Mike
Object Type: Report
System: The UNT Digital Library
WABASH RIVER INTEGRATED METHANOL AND POWER PRODUCTION FROM CLEAN COAL TECHNOLGIES (IMPPCCT) (open access)

WABASH RIVER INTEGRATED METHANOL AND POWER PRODUCTION FROM CLEAN COAL TECHNOLGIES (IMPPCCT)

The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project is evaluating integrated electrical power generation and methanol production through clean coal technologies. The project is under the leadership of ConocoPhillips Company (COP), after it acquired Gasification Engineering Corporation (GEC) and the E-Gas gasification technology from Global Energy in July 2003. The project has completed Phase I, and is currently in Phase II of development. The two project phases include: (1) Feasibility study and conceptual design for an integrated demonstration facility at Global Energy's existing Wabash River Energy Limited (WREL) plant in West Terre Haute, Indiana, and for a fence-line commercial embodiment plants (CEP) operated at Dow Chemical or Dow Corning chemical plant locations; and (2) Research, development, and testing (RD&T) to define any technology gaps or critical design and integration issues. The Phase I of this project was supported by a multi-industry team consisting of Air Products and Chemicals, Inc., Dow Chemical Company, Dow Corning Corporation, Methanex Corporation, and Siemens Westinghouse Power Corporation, while Phase II is supported by Gas Technology Institute, TDA Research Inc., and Nucon International, Inc. The WREL integrated gasification combined cycle (IGCC) facility was designed, constructed, and operated under a project …
Date: March 26, 2004
Creator: Tsang, Albert C.
Object Type: Report
System: The UNT Digital Library
Active control for turbulent premixed flame simulations (open access)

Active control for turbulent premixed flame simulations

Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.
Date: March 26, 2004
Creator: Bell, John B.; Day, Marcus S.; Grcar, Joseph F. & Lijewski, Michael J.
Object Type: Article
System: The UNT Digital Library
INTELLIGENT MONITORING SYSTEM WITH HIGH TEMPERATURE DISTRIBUTED FIBEROPTIC SENSOR FOR POWER PLANT COMBUSTION PROCESSES (open access)

INTELLIGENT MONITORING SYSTEM WITH HIGH TEMPERATURE DISTRIBUTED FIBEROPTIC SENSOR FOR POWER PLANT COMBUSTION PROCESSES

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, improvement was made on the performance of in-fiber grating fabricated in single crystal sapphire fibers, test was performed on the grating performance of single crystal sapphire fiber with new fabrication methods, and the fabricated grating was applied to high temperature sensor. Under Task 2, models obtained from 3-D modeling of the Demonstration Boiler were used to …
Date: December 26, 2004
Creator: Lee, Kwang Y.; Yin, Stuart S. & Boheman, Andre
Object Type: Report
System: The UNT Digital Library
Heavy flavor production at the Tevatron (open access)

Heavy flavor production at the Tevatron

Using a subset of the current Run II data, the CDF and D0 have performed several measurements on heavy flavor production. In this paper, we present a new measurement of prompt charm meson production by CDF. We also report the latest CDF II measurements of inclusive J/{Psi} production and b-production without requirement of minimum transverse momentum on J/{Psi} and b-quark. They are the first measurements of the total inclusive J/{Psi} and b quark cross section in the central rapidity region at a hadron collider. The results of J/{Psi} cross section as a function of rapidity, and b-jet production cross section measured by D0 are also reviewed.
Date: February 26, 2004
Creator: Chen, Chunhui
Object Type: Article
System: The UNT Digital Library
Virtual data in CMS production (open access)

Virtual data in CMS production

Initial applications of the GriPhyN Chimera Virtual Data System have been performed within the context of CMS Production of Monte Carlo Simulated Data. The GriPhyN Chimera system consists of four primary components: (1) a Virtual Data Language, which is used to describe virtual data products, (2) a Virtual Data Catalog, which is used to store virtual data entries, (3) an Abstract Planner, which resolves all dependencies of a particular virtual data product and forms a location and existence independent plan, (4) a Concrete Planner, which maps an abstract, logical plan onto concrete, physical grid resources accounting for staging in/out files and publishing results to a replica location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual data products using the Virtual Data Language. Subsequently, a prototype workflow manager, known as WorkRunner, is used to schedule the instantiation of virtual data products across a grid.
Date: August 26, 2004
Creator: Arbree, A.
Object Type: Article
System: The UNT Digital Library
Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants (open access)

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

During this quarter, work was focused on testing layered composite membranes under varying feed stream flow rates at high pressure. By optimizing conditions, H{sub 2} permeation rates as high as 423 mL {center_dot} min{sup -1} {center_dot} cm{sup -2} at 440 C were measured. Membrane stability was investigated by comparison to composite alloy membranes. Permeation of alloyed membranes showed a strong dependence on the alloying element. Impedance analysis was used to investigate bulk and grain boundary conductivity in cermets. Thin film cermet deposition procedures were developed, hydrogen dissociation catalysts were evaluated, and hydrogen separation unit scale-up issues were addressed.
Date: July 26, 2004
Creator: Evenson, Carl R.; Sammells, Anthony F.; Mackay, Richard; Treglio, Richard; Rolfe, Sara L.; Blair, Richard et al.
Object Type: Report
System: The UNT Digital Library
2003 Chemical Engineering Division annual technical report. (open access)

2003 Chemical Engineering Division annual technical report.

The Chemical Engineering Division is one of six divisions within the Engineering Research Directorate at Argonne National Laboratory, one of the U.S. government's oldest and largest research laboratories. The University of Chicago oversees the laboratory on behalf of the U.S. Department of Energy (DOE). Argonne's mission is to conduct basic scientific research, to operate national scientific facilities, to enhance the nation's energy resources, to promote national security, and to develop better ways to manage environmental problems. Argonne has the further responsibility of strengthening the nation's technology base by developing innovative technology and transferring it to industry. The Division is a diverse early-stage engineering organization, specializing in the treatment of spent nuclear fuel, development of advanced electrochemical power sources, and management of both high- and low-level nuclear wastes. Additionally, the Division operates the Analytical Chemistry Laboratory, which provides a broad range of analytical services to Argonne and other organizations. The Division is multidisciplinary. Its people have formal training in chemistry; physics; materials science; and electrical, mechanical, chemical, and nuclear engineering. They are specialists in electrochemistry, ceramics, metallurgy, catalysis, materials characterization, nuclear magnetic resonance, repository science, and the nuclear fuel cycle. Our staff have experience working in and collaborating with university, industry …
Date: April 26, 2004
Creator: Lewis, D.; Graziano, D.; Miller, J. F. & Vandegrift, G.
Object Type: Report
System: The UNT Digital Library
Variational formulation of the Gardner's restacking algorithm (open access)

Variational formulation of the Gardner's restacking algorithm

The incompressibility of the phase flow of Hamiltonian wave-plasma interactions restrains the class of realizable wave-driven transformations of the particle distribution. After the interaction, the distribution remains composed of the original phase-space elements, or local densities, which are only rearranged (''restacked'') by the wave. A variational formalism is developed to study the corresponding limitations on the energy and momentum transfer. A case of particular interest is a toroidal plasma immersed in a dc magnetic field. The restacking algorithm by Gardner [Phys. Fluids 6, 839 (1963)] is formulated precisely. The minimum energy state for a plasma with a given current is determined
Date: April 26, 2004
Creator: Dodin, I. Y. & Fisch, N. J.
Object Type: Report
System: The UNT Digital Library
MCRUNJOB: A High energy physics workflow planner for grid production processing (open access)

MCRUNJOB: A High energy physics workflow planner for grid production processing

McRunjob is a powerful grid workflow manager used to manage the generation of large numbers of production processing jobs in High Energy Physics. In use at both the DZero and CMS experiments, McRunjob has been used to manage large Monte Carlo production processing since 1999 and is being extended to uses in regular production processing for analysis and reconstruction. Described at CHEP 2001, McRunjob converts core metadata into jobs submittable in a variety of environments. The powerful core metadata description language includes methods for converting the metadata into persistent forms, job descriptions, multi-step workflows, and data provenance information. The language features allow for structure in the metadata by including full expressions, namespaces, functional dependencies, site specific parameters in a grid environment, and ontological definitions. It also has simple control structures for parallelization of large jobs. McRunjob features a modular design which allows for easy expansion to new job description languages or new application level tasks.
Date: August 26, 2004
Creator: Graham, Gregory E.
Object Type: Article
System: The UNT Digital Library
Rating energy efficiency and sustainability in laboratories: Results and lessons from the Labs21 program (open access)

Rating energy efficiency and sustainability in laboratories: Results and lessons from the Labs21 program

Laboratories are very energy intensive, with significant opportunities for improved efficiency. However, their inherent complexity and variety makes benchmarking of their energy and environmental performance a unique and challenging task. Furthermore, laboratories have a myriad of health and safety requirements that significantly affect energy use, adding complexity to their benchmarking. The Labs21 program, a joint program of the US EPA and US DOE, has developed two resources specifically for assessing laboratory energy and environmental performance: (1) An energy benchmarking tool which allows users to compare laboratories using a standard set of building and system level energy use metrics. (2) The Environmental Performance Criteria (EPC) a point-based rating system that builds on the LEED(TM) green building rating system, designed to score overall environmental performance. In this paper, for each of these tools we present the underlying methodology and results from their use. For the benchmarking tool, we contrast our approach, which includes a simulation model-based component, with those used for other building types. We also present selected results from data collection and analysis of about 40 private and public sector laboratory facilities. In the case of the EPC, we describe variations from the LEED standard, focusing on the energy credits. Finally, …
Date: May 26, 2004
Creator: Mathew, Paul; Sartor, Dale; van Geet, Otto & Reilly, Sue
Object Type: Article
System: The UNT Digital Library
Calcium Carbonate Production by Coccolithophorid Algae in Long Term, Carbon Dioxide Sequestration (open access)

Calcium Carbonate Production by Coccolithophorid Algae in Long Term, Carbon Dioxide Sequestration

Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids single-celled, marine algae that are the major global producers of calcium carbonate to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could …
Date: April 26, 2004
Creator: Fabry, V. J.
Object Type: Report
System: The UNT Digital Library
Radiation shielding calculations for MuCool test area at Fermilab (open access)

Radiation shielding calculations for MuCool test area at Fermilab

The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets being developed for cooling intense muon beams. In this shielding study the results of Monte Carlo radiation shielding calculations performed using the MARS14 code for the MuCool Test Area and including the downstream portion of the target hall and berm around it, access pit, service building, and parking lot are presented and discussed within the context of the proposed MTA experimental configuration.
Date: May 26, 2004
Creator: Rakhno, Igor & Johnstone, Carol
Object Type: Report
System: The UNT Digital Library
Hydrogen Production in Radioactive Solutions in the Defense Waste Processing Facility (open access)

Hydrogen Production in Radioactive Solutions in the Defense Waste Processing Facility

In the radioactive slurries and solutions to be processed in the Defense Waste Processing Facility (DWPF), hydrogen will be produced continuously by radiolysis. This production results from alpha, beta, and gamma rays from decay of radionuclides in the slurries and solutions interacting with the water. More than 1000 research reports have published data concerning this radiolytic production. The results of these studies have been reviewed in a comprehensive monograph. Information about radiolytic hydrogen production from the different process tanks is necessary to determine air purge rates necessary to prevent flammable mixtures from accumulating in the vapor spaces above these tanks. Radiolytic hydrogen production rates are usually presented in terms of G values or molecules of hydrogen produced per 100ev of radioactive decay energy absorbed by the slurry or solution. With the G value for hydrogen production, G(H2), for a particular slurry and the concentrations of radioactive species in that slurry, the rate of H2 production for that slurry can be calculated. An earlier investigation estimated that the maximum rate that hydrogen could be produced from the sludge slurry stream to the DWPF is with a G value of 0.45 molecules per 100ev of radioactive decay energy sorbed by the slurry.
Date: May 26, 2004
Creator: CRAWFORD, CHARLES L.
Object Type: Report
System: The UNT Digital Library
Neptunium Disposal to the Savannah River Site Tank Farm (open access)

Neptunium Disposal to the Savannah River Site Tank Farm

Researchers investigated the neutralization of an acidic neptunium solution from a Savannah River Site (SRS) processing canyon and the properties of the resulting slurry to determine the feasibility of disposal in the SRS tank farm. The acidic solution displayed no properties that precluded the proposed disposal route. Neutralization of the acidic neptunium forms a 4 wt per cent slurry of precipitated metal hydroxides. The insoluble solids consist largely of iron (92 per cent) and neptunium hydroxides (2 per cent). The concentration of soluble neptunium remaining after neutralization equaled much less than previous solubility measurements predicted. Researchers used an apparatus similar to an Ostwald-type viscometer to estimate the consistency of the neptunium slurry with the solids present. The yield stress and consistency of the 4 wt per cent slurry will allow transfer through the tank farm, although concentration of the insoluble solids above 4 wt per cent may cause significant problems due to increased consistency and yield stress. The consistency of the 4 wt per cent slurry is 7.6 centipoise (cP) with a yield stress less than 1 Pascal (Pa). The neptunium slurry, when combined with actual washed radioactive sludge, slightly reduces the yield stress and consistency of the sludge and …
Date: February 26, 2004
Creator: Walker, D. D.
Object Type: Article
System: The UNT Digital Library
Geologic Framework Model (GFM2000) (open access)

Geologic Framework Model (GFM2000)

The purpose of this report is to document the geologic framework model, version GFM2000 with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, and the differences between GFM2000 and previous versions. The version number of this model reflects the year during which the model was constructed. This model supersedes the previous model version, documented in Geologic Framework Model (GFM 3.1) (CRWMS M&O 2000 [DIRS 138860]). The geologic framework model represents a three-dimensional interpretation of the geology surrounding the location of the monitored geologic repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain. The geologic framework model encompasses and is limited to an area of 65 square miles (168 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the geologic framework model (shown in Figure 1-1) were chosen to encompass the exploratory boreholes and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The upper surface of the model is made up of the surface topography and the depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. …
Date: August 26, 2004
Creator: Vogt, T.
Object Type: Report
System: The UNT Digital Library
Phylogenetic & Physiological Profiling of Microbial Communities of Contaminated Soils/Sediments: Identifying Microbial consortia... (open access)

Phylogenetic & Physiological Profiling of Microbial Communities of Contaminated Soils/Sediments: Identifying Microbial consortia...

The goals of this study were: (1) survey the microbial community in soil samples from a site contaminated with heavy metals using new rapid molecular techniques that are culture-independent; (2) identify phylogenetic signatures of microbial populations that correlate with metal ion contamination; and (3) cultivate these diagnostic strains using traditional as well as novel cultivation techniques in order to identify organisms that may be of value in site evaluation/management or bioremediation.
Date: May 26, 2004
Creator: Marsh, Terence L.
Object Type: Report
System: The UNT Digital Library
Quantum leaps in philosophy of mind: Reply to Bourget'scritique (open access)

Quantum leaps in philosophy of mind: Reply to Bourget'scritique

David Bourget has raised some conceptual and technical objections to my development of von Neumann's treatment of the Copenhagen idea that the purely physical process described by the Schroedinger equation must be supplemented by a psychophysical process called the choice of the experiment by Bohr and Process 1 by von Neumann. I answer here each of Bourget's objections.
Date: July 26, 2004
Creator: Stapp, Henry P.
Object Type: Article
System: The UNT Digital Library
Stabilization of Sawtooth Oscillations by the Circulating Energetic Ions (open access)

Stabilization of Sawtooth Oscillations by the Circulating Energetic Ions

The influence of the well-circulating energetic ions on the ideal kink instability and semi-collisional tearing mode are studied. It is found that the precession of these ions can be a key factor that affects the instability: it can lead to the stabilization of the mentioned instabilities, the effect being weakly dependent on the direction of the injection. The developed theory is consistent with the experimental observations of the stabilization of sawtooth oscillations during the negative-ion-based neutral beam injection in JT-60U.
Date: May 26, 2004
Creator: Kolesnichenko, Ya.I.; Marchenko, V.S. & R.B.White
Object Type: Report
System: The UNT Digital Library
Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers (open access)

Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers

OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The …
Date: March 26, 2004
Creator: Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan & Adinolfi, Pierangelo
Object Type: Report
System: The UNT Digital Library