WorldWideScience

Sample records for model laboratory combustor

  1. Combustor Modelling

    Science.gov (United States)

    1980-02-01

    a teuto 014aceo 0-oiuato 4 ajj 210- I 14 *Experiments l~~lamCID - l2 C15 model+ Aida ditane &Gray medium K .2 a Experiments hont target n-IO a0 deawa...possibilita di valutazione dello scambio termico in focolai di caldaie per ricaldamento"I Atti E Rassegna Tecnica Societa ingegneri e arc~hitetti in Torino

  2. Modelling of Biomass Combustor : Final assignment energy from biomass

    NARCIS (Netherlands)

    Ammerlaan, R.; Van den Hill, E.J.; Kaas, A.W.S.; Verburg, M.W.

    2010-01-01

    In this study a 1.1 MW fluidized bed combustor is modeled. A literature study is performed on aspects which determine the characteristics of the combustor. A model is set up and calculations for the design of the Fluidized Bed Combustor (FBC) are performed. Characteristics are calculated for the

  3. Emissions from laboratory combustor tests of manufactured wood products

    Energy Technology Data Exchange (ETDEWEB)

    Wilkening, R.; Evans, M.; Ragland, K. [Univ. of Wisconsin, Madison, WI (United States); Baker, A. [USDA Forest Products Lab., Madison, WI (United States)

    1993-12-31

    Manufactured wood products contain wood, wood fiber, and materials added during manufacture of the product. Manufacturing residues and the used products are burned in a furnace or boiler instead of landfilling. Emissions from combustion of these products contain additional compounds from the combustion of non-wood material which have not been adequately characterized to specify the best combustion conditions, emissions control equipment, and disposal procedures. Total hydrocarbons, formaldehyde, higher aldehydes and carbon monoxide emissions from aspen flakeboard and aspen cubes were measured in a 76 mm i.d. by 1.5 m long fixed bed combustor as a function of excess oxygen, and temperature. Emissions of hydrocarbons, aldehydes and CO from flakeboard and from clean aspen were very sensitive to average combustor temperature and excess oxygen. Hydrocarbon and aldehyde emissions below 10 ppM were achieved with 5% excess oxygen and 1,200{degrees}C average temperature for aspen flakeboard and 1,100{degrees}C for clean aspen at a 0.9 s residence time. When the average temperature decreased below these levels, the emissions increased rapidly. For example, at 950{degrees}C and 5% excess oxygen the formaldehyde emissions were over 1,000 ppM. These laboratory tests reinforce the need to carefully control the temperature and excess oxygen in full-scale wood combustors.

  4. Numerical optimization of laboratory combustor geometry for NO suppression

    International Nuclear Information System (INIS)

    Mazaheri, Karim; Shakeri, Alireza

    2016-01-01

    Highlights: • A five-step kinetics for NO and CO prediction is extracted from GRI-3.0 mechanism. • Accuracy and applicability of this kinetics for numerical optimization were shown. • Optimized geometry for a combustor was determined using the combined process. • NO emission from optimized geometry is found 10.3% lower than the basis geometry. - Abstract: In this article, geometry optimization of a jet stirred reactor (JSR) combustor has been carried out for minimum NO emissions in methane oxidation using a combined numerical algorithm based on computational fluid dynamics (CFD) and differential evolution (DE) optimization. The optimization algorithm is also used to find a fairly accurate reduced mechanism. The combustion kinetics is based on a five-step mechanism with 17 unknowns which is obtained using an optimization DE algorithm for a PSR–PFR reactor based on GRI-3.0 full mechanism. The optimization design variables are the unknowns of the five-step mechanism and the cost function is the concentration difference of pollutants obtained from the 5-step mechanism and the full mechanism. To validate the flow solver and the chemical kinetics, the computed NO at the outlet of the JSR is compared with experiments. To optimize the geometry of a combustor, the JSR combustor geometry is modeled using three parameters (i.e., design variables). An integrated approach using a flow solver and the DE optimization algorithm produces the lowest NO concentrations. Results show that the exhaust NO emission for the optimized geometry is 10.3% lower than the original geometry, while the inlet temperature of the working fluid and the concentration of O 2 are operating constraints. In addition, the concentration of CO pollutant is also much less than the original chamber.

  5. Computational model of a whole tree combustor

    Energy Technology Data Exchange (ETDEWEB)

    Bryden, K.M.; Ragland, K.W. [Univ. of Wisconsin, Madison, WI (United States)

    1993-12-31

    A preliminary computational model has been developed for the whole tree combustor and compared to test results. In the simulation model presented hardwood logs, 15 cm in diameter are burned in a 4 m deep fuel bed. Solid and gas temperature, solid and gas velocity, CO, CO{sub 2}, H{sub 2}O, HC and O{sub 2} profiles are calculated. This deep, fixed bed combustor obtains high energy release rates per unit area due to the high inlet air velocity and extended reaction zone. The lowest portion of the overall bed is an oxidizing region and the remainder of the bed acts as a gasification and drying region. The overfire air region completes the combustion. Approximately 40% of the energy is released in the lower oxidizing region. The wood consumption rate obtained from the computational model is 4,110 kg/m{sup 2}-hr which matches well the consumption rate of 3,770 kg/m{sup 2}-hr observed during the peak test period of the Aurora, MN test. The predicted heat release rate is 16 MW/m{sup 2} (5.0*10{sup 6} Btu/hr-ft{sup 2}).

  6. Life assessment of combustor liner using unified constitutive models

    Science.gov (United States)

    Tong, M. T.; Thompson, R. L.

    1988-01-01

    Hot section components of gas turbine engines are subject to severe thermomechanical loads during each mission cycle. Inelastic deformation can be induced in localized regions leading to eventual fatigue cracking. Assessment of durability requires reasonably accurate calculation of the structural response at the critical location for crack initiation. In recent years nonlinear finite element computer codes have become available for calculating inelastic structural response under cyclic loading. NASA-Lewis sponsored the development of unified constitutive material models and their implementation in nonlinear finite element computer codes for the structural analysis of hot section components. These unified models were evaluated with regard to their effect on the life prediction of a hot section component. The component considered was a gas turbine engine combustor liner. A typical engine mission cycle was used for the thermal and structural analyses. The analyses were performed on a CRAY computer using the MARC finite element code. The results were compared with laboratory test results, in terms of crack initiation lives.

  7. Thermoacoustic analysis of the dynamic pressure inside a model combustor during limit cycle oscillations

    NARCIS (Netherlands)

    Alemela, P.R.; Roman Casado, J.C.; Tarband Veeraraghavan, S.K.; Kok, Jacobus B.W.

    2013-01-01

    In this work comprehensive experimental and numerical studies incorporating the most relevant physical mechanisms causing limit cycle pressure and combustion rate oscillations (LCO) in a laboratory scale combustor will be discussed. The strong interaction between the aerodynamics-combustion-acoustic

  8. Development of an analytical model to assess fuel property effects on combustor performance

    Science.gov (United States)

    Sutton, R. D.; Troth, D. L.; Miles, G. A.; Riddlebaugh, S. M.

    1987-01-01

    A generalized first-order computer model has been developed in order to analytically evaluate the potential effect of alternative fuels' effects on gas turbine combustors. The model assesses the size, configuration, combustion reliability, and durability of the combustors required to meet performance and emission standards while operating on a broad range of fuels. Predictions predicated on combustor flow-field determinations by the model indicate that fuel chemistry, as defined by hydrogen content, exerts a significant influence on flame retardation, liner wall temperature, and smoke emission.

  9. An Engineering Model for Prediction of Waste Incineration in a Dump Combustor

    National Research Council Canada - National Science Library

    Arunajatesan, S

    1997-01-01

    An engineering model that can be used to obtain predictions of axial distributions of temperature and species concentrations in complex flows has been formulated and applied to waste incineration in a dump combustor...

  10. Analysis of a high-temperature coal combustor according to a one-dimensional flow model

    Energy Technology Data Exchange (ETDEWEB)

    Chung, P M; Smith, R S

    1977-10-01

    A steady state, one-dimensional analysis for a high temperature coal combustor is presented. An existing solution of solid fuel ignition is employed to describe the ignition of the coal particles. A one-dimensional flow model with radiative heat loss is then constructed to describe the subsequent vaporization of ash and devolatilization, combustion, and gasification of the coal. Combustion is considered to take place either at a flame sheet in the diffusion layer surrounding each particle or at the particle surface. The combustion products are considered to be redistributed in the main gas stream of the combustor according to simplified chemical equilibrium criteria. A simplified devolatilization rate law is formulated, which incorporates in a tractable manner the various competing reactions within the coal particle. Data are presented for the variation of temperatures and mass fractions with position in the combustor and for the influence of various parameters on combustor performance.

  11. Flashback behavior in a model swirl combustor at elevated pressure

    Science.gov (United States)

    Ranjan, Rakesh; Ebi, Dominik; Clemens, Noel

    2014-11-01

    Understanding of combustion physics at high pressure is essential for safe and efficient operation of gas turbine combustors. A new optically-accessible elevated pressure combustion facility has been developed for this purpose. The modular design of the chamber allows applying various optical diagnostic techniques and the installation of different types of combustors. In the current study, the effect of pressure on boundary layer flashback in lean-premixed swirl flames is investigated. Mixtures of hydrogen and methane at different equivalence ratios are tested. High-speed chemiluminescence imaging is employed to study the upstream flame propagation inside the mixing tube, which allows comparison to previous results of flashback at atmospheric pressure.

  12. Parametric Modeling Investigation of a Radially-Staged Low-Emission Aviation Combustor

    Science.gov (United States)

    Heath, Christopher M.

    2016-01-01

    Aviation gas-turbine combustion demands high efficiency, wide operability and minimal trace gas emissions. Performance critical design parameters include injector geometry, combustor layout, fuel-air mixing and engine cycle conditions. The present investigation explores these factors and their impact on a radially staged low-emission aviation combustor sized for a next-generation 24,000-lbf-thrust engine. By coupling multi-fidelity computational tools, a design exploration was performed using a parameterized annular combustor sector at projected 100% takeoff power conditions. Design objectives included nitrogen oxide emission indices and overall combustor pressure loss. From the design space, an optimal configuration was selected and simulated at 7.1, 30 and 85% part-power operation, corresponding to landing-takeoff cycle idle, approach and climb segments. All results were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Species concentrations were solved directly using a reduced 19-step reaction mechanism for Jet-A. Turbulence closure was obtained using a nonlinear K-epsilon model. This research demonstrates revolutionary combustor design exploration enabled by multi-fidelity physics-based simulation.

  13. Flow aerodynamics modeling of an MHD swirl combustor - calculations and experimental verification

    International Nuclear Information System (INIS)

    Gupta, A.K.; Beer, J.M.; Louis, J.F.; Busnaina, A.A.; Lilley, D.G.

    1981-01-01

    This paper describes a computer code for calculating the flow dynamics of constant density flow in the second stage trumpet shaped nozzle section of a two stage MHD swirl combustor for application to a disk generator. The primitive pressure-velocity variable, finite difference computer code has been developed to allow the computation of inert nonreacting turbulent swirling flows in an axisymmetric MHD model swirl combustor. The method and program involve a staggered grid system for axial and radial velocities, and a line relaxation technique for efficient solution of the equations. Tue produces as output the flow field map of the non-dimensional stream function, axial and swirl velocity. 19 refs

  14. Investigation of Methane Oxy-Fuel Combustion in a Swirl-Stabilised Gas Turbine Model Combustor

    Directory of Open Access Journals (Sweden)

    Mao Li

    2017-05-01

    Full Text Available CO2 has a strong impact on both operability and emission behaviours in gas turbine combustors. In the present study, an atmospheric, preheated, swirl-stabilised optical gas turbine model combustor rig was employed. The primary objectives were to analyse the influence of CO2 on the fundamental characteristics of combustion, lean blowout (LBO limits, CO emission and flame structures. CO2 dilution effects were examined with three preheating temperatures (396.15, 431.15, and 466.15 K. The fundamental combustion characteristics were studied utilising chemical kinetic simulations. To study the influence of CO2 on the operational range of the combustor, equivalence ratio (Ф was varied from stoichiometric conditions to the LBO limits. CO emissions were measured at the exit of the combustor using a water-cooled probe over the entire operational range. The flame structures and locations were characterised by performing CH chemiluminescence imaging. The inverse Abel transformation was used to analyse the CH distribution on the axisymmetric plane of the combustor. Chemical kinetic modelling indicated that the CO2 resulted in a lower reaction rate compared with the CH4/air flame. Fundamental combustion properties such as laminar flame speed, ignition delay time and blowout residence time were found to be affected by CO2. The experimental results revealed that CO2 dilution resulted in a narrower operational range for the equivalence ratio. It was also found that CO2 had a strong inhibiting effect on CO burnout, which led to a higher concentration of CO in the combustion exhaust. CH chemiluminescence showed that the CO2 dilution did not have a significant impact on the flame structure.

  15. Sampling related issues in pod-based model reduction of simplified circulating fluidised bed combustor model

    Directory of Open Access Journals (Sweden)

    Bizon Katarzyna

    2015-09-01

    Full Text Available Over the last decades the method of proper orthogonal decomposition (POD has been successfully employed for reduced order modelling (ROM in many applications, including distributed parameter models of chemical reactors. Nevertheless, there are still a number of issues that need further investigation. Among them, the policy of the collection of representative ensemble of experimental or simulation data, being a starting and perhaps most crucial point of the POD-based model reduction procedure. This paper summarises the theoretical background of the POD method and briefly discusses the sampling issue. Next, the reduction procedure is applied to an idealised model of circulating fluidised bed combustor (CFBC. Results obtained confirm that a proper choice of the sampling strategy is essential for the modes convergence however, even low number of observations can be sufficient for the determination of the faithful dynamical ROM.

  16. Reduced Order Modeling of Combustion Instability in a Gas Turbine Model Combustor

    Science.gov (United States)

    Arnold-Medabalimi, Nicholas; Huang, Cheng; Duraisamy, Karthik

    2017-11-01

    Hydrocarbon fuel based propulsion systems are expected to remain relevant in aerospace vehicles for the foreseeable future. Design of these devices is complicated by combustion instabilities. The capability to model and predict these effects at reduced computational cost is a requirement for both design and control of these devices. This work focuses on computational studies on a dual swirl model gas turbine combustor in the context of reduced order model development. Full fidelity simulations are performed utilizing URANS and Hybrid RANS-LES with finite rate chemistry. Following this, data decomposition techniques are used to extract a reduced basis representation of the unsteady flow field. These bases are first used to identify sensor locations to guide experimental interrogations and controller feedback. Following this, initial results on developing a control-oriented reduced order model (ROM) will be presented. The capability of the ROM will be further assessed based on different operating conditions and geometric configurations.

  17. Parameterised Model of 2D Combustor Exit Flow Conditions for High-Pressure Turbine Simulations

    Directory of Open Access Journals (Sweden)

    Marius Schneider

    2017-12-01

    Full Text Available An algorithm is presented generating a complete set of inlet boundary conditions for Reynolds-averaged Navier–Stokes computational fluid dynamics (RANS CFD of high-pressure turbines to investigate their interaction with lean and rich burn combustors. The method shall contribute to understanding the sensitivities of turbine aerothermal performance in a systematic approach. The boundary conditions are based on a set of input parameters controlling velocity, temperature, and turbulence fields. All other quantities are derived from operating conditions and additional modelling assumptions. The algorithm is coupled with a CFD solver by applying the generated profiles as inlet boundary conditions. The successive steps to derive consistent flow profiles are described and results are validated against flow fields extracted from combustor CFD.

  18. A numerical study of mixing and combustion in hypervelocity flows through a scramjet combustor model

    Science.gov (United States)

    Krishamurthy, Ramesh

    1993-01-01

    Interest in high speed, air-breathing propulsion systems such as scramjets has revived in recent years fueled to a large extent by the National Aerospace Plane (NASP) program. These vehicles are expected to fly trans-atmospheric and as a consequence, the Mach number level within the engine/combustor would be rather high (M greater than 5). Ground based testing of such scramjet engines requires a facility that can not only achieve the right Mach number, but also have the proper pressures and temperatures to simulate the combustion processes. At present, only pulse type facilities can provide such high enthalpy flows. The newest of these is the free-piston shock tunnel, T5 located at GALCIT. Recently, a generic combustor model was tested in T5, and the experimental data from that study is analyzed in the present report. The available experimental data from T5 are essentially the static pressures on the injection wall and the one opposite to it. Thus, a principal aim of the present study was to validate the available experimental data by using a proven CFD tool and then investigate the performance characteristics of the combustor model, such as, the mixing efficiency and combustion efficiency. For this purpose, in this study, the code GASP has been used.

  19. Modeling the integration of thermoelectrics in anode exhaust combustors for waste heat recovery in fuel cell systems

    Science.gov (United States)

    Maghdouri Moghaddam, Anita

    Recently developed small-scale hydrocarbon-fueled fuel cell systems for portable power under 1 kW have overall system efficiencies typically no higher than 30-35%. This study explores the possibility of using of thermoelectric waste heat recovery in anode exhaust combustors to improve the fuel cell system efficiencies by as much as 4-5% points and further to reduce required battery power during system start-up. Two models were used to explore this. The first model simulated an integrated SOFC system with a simplified catalytic combustor model with TEs integrated between the combustor and air preheating channels for waste heat recovery. This model provided the basis for assessing how much additional power can achieve during SOFC operation as a function of fuel cell operating conditions. Results for the SOFC system indicate that while the TEs may recover as much as 4% of the total fuel energy into the system, their benefit is reduced in part because they reduce the waste heat transferred back to the incoming air stream and thereby lower the SOFC operating temperatures and operating efficiencies. A second model transient model of a TE-integrated catalytic combustor explored the performance of the TEs during transient start-up of the combustor. This model incorporated more detailed catalytic combustion chemistry and enhanced cooling air fin heat transfer to show the dynamic heating of the integrated combustor. This detailed model provided a basis for exploring combustor designs and showed the importance of adequate reactant preheating when burning exhaust from a reformer during start-up for the TEs to produce significant power to reduce the size of system batteries for start-up.

  20. Laboratory of Biological Modeling

    Data.gov (United States)

    Federal Laboratory Consortium — The Laboratory of Biological Modeling is defined by both its methodologies and its areas of application. We use mathematical modeling in many forms and apply it to a...

  1. Current Status of Post-combustor Trace Chemistry Modeling and Simulation at NASA Glenn Research Center

    Science.gov (United States)

    Wey, Thomas; Liu, Nan-Suey

    2003-01-01

    The overall objective of the current effort at NASA GRC is to evaluate, develop, and apply methodologies suitable for modeling intra-engine trace chemical changes over post combustor flow path relevant to the pollutant emissions from aircraft engines. At the present time, the focus is the high pressure turbine environment. At first, the trace chemistry model of CNEWT were implemented into GLENN-HT as well as NCC. Then, CNEWT, CGLENN-HT, and NCC were applied to the trace species evolution in a cascade of Cambridge University's No. 2 rotor and in a turbine vane passage. In general, the results from these different codes provide similar features. However, the details of some of the quantities of interest can be sensitive to the differences of these codes. This report summaries the implementation effort and presents the comparison of the No. 2 rotor results obtained from these different codes. The comparison of the turbine vane passage results is reported elsewhere. In addition to the implementation of trace chemistry model into existing CFD codes, several pre/post-processing tools that can handle the manipulations of the geometry, the unstructured and structured grids as well as the CFD solutions also have been enhanced and seamlessly tied with NCC, CGLENN-HT, and CNEWT. Thus, a complete CFD package consisting of pre/post-processing tools and flow solvers suitable for post-combustor intra-engine trace chemistry study is assembled.

  2. HAZARDOUS WASTE INCINERATION: THE IN-SITU CAPTURE OF LEAD BY SORBENTS IN A LABORATORY DOWNFLOW COMBUSTOR

    Science.gov (United States)

    The paper discusses experiments on a 17-kW downflow combustor to determine how sorbent injection into the postflame influenced the particle size distribution of a lead (Pb) aerosol formed from a surrogate Pb-containing waste. n the absence of chlorine (CI), the Pb aerosol size di...

  3. Preliminary study of NO{sub x}, CO, and lean blowoff in a piloted-lean premixed combustor. Part 2: Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J.C.; Mello, J.P.; Mellor, A.M. [Vanderbilt Univ., Nashville, TN (United States). Combustion and Propulsion Group; Malte, P.C. [Univ. of Washington, Seattle, WA (United States). Dept. of Mechanical Engineering

    1996-05-01

    The characteristic time model (CTM) is a semi-empirical model for gas turbine emissions and performance. The CTM represents the essence of the dominant physical subprocesses related to combustor performance in terms of characteristic times. Properly formulated, these characteristic times account for variations in combustor geometry, fuel characteristics, and operating conditions. In this work, the capability of the CTM to correlate the piloted-LP NO{sub x}, CO and blowoff data described in part 1 of this paper is assessed.

  4. Impact of ethane and propane variation in natural gas on the performance of a model gas turbine combustor

    OpenAIRE

    Flores, RM; McDonell, VG; Samuelsen, GS

    2003-01-01

    In the area of stationary power generation, there exists a growing interest in understanding the role that gaseous fuel composition plays on the performance of natural gas-fired gas turbine systems. In this study, an atmospherically fired model gas turbine combustor with a fuel flexible fuel/air premixer is employed to investigate the impact of significant amounts of ethane and propane addition into a baseline natural gas fuel supply. The impacts of these various fuel compositions, in terms o...

  5. Mercury emissions during cofiring of sub-bituminous coal and biomass (chicken waste, wood, coffee residue, and tobacco stalk) in a laboratory-scale fluidized bed combustor.

    Science.gov (United States)

    Cao, Yan; Zhou, Hongcang; Fan, Junjie; Zhao, Houyin; Zhou, Tuo; Hack, Pauline; Chan, Chia-Chun; Liou, Jian-Chang; Pan, Wei-Ping

    2008-12-15

    Four types of biomass (chicken waste, wood pellets, coffee residue, and tobacco stalks) were cofired at 30 wt % with a U.S. sub-bituminous coal (Powder River Basin Coal) in a laboratory-scale fluidized bed combustor. A cyclone, followed by a quartz filter, was used for fly ash removal during tests. The temperatures of the cyclone and filter were controlled at 250 and 150 degrees C, respectively. Mercury speciation and emissions during cofiring were investigated using a semicontinuous mercury monitor, which was certified using ASTM standard Ontario Hydra Method. Test results indicated mercury emissions were strongly correlative to the gaseous chlorine concentrations, but not necessarily correlative to the chlorine contents in cofiring fuels. Mercury emissions could be reduced by 35% during firing of sub-bituminous coal using only a quartz filter. Cofiring high-chlorine fuel, such as chicken waste (Cl = 22340 wppm), could largely reduce mercury emissions by over 80%. When low-chlorine biomass, such as wood pellets (Cl = 132 wppm) and coffee residue (Cl = 134 wppm), is cofired, mercury emissions could only be reduced by about 50%. Cofiring tobacco stalks with higher chlorine content (Cl = 4237 wppm) did not significantly reduce mercury emissions. This was also true when limestone was added while cofiring coal and chicken waste because the gaseous chlorine was reduced in the freeboard of the fluidized bed combustor, where the temperature was generally below 650 degrees C without addition of the secondary air. Gaseous speciated mercury in flue gas after a quartz filter indicated the occurrence of about 50% of total gaseous mercury to be the elemental mercury for cofiring chicken waste, but occurrence of above 90% of the elemental mercury for all other cases. Both the higher content of alkali metal oxides or alkali earth metal oxides in tested biomass and the occurrence of temperatures lower than 650 degrees C in the upper part of the fluidized bed combustor seemed to be

  6. Experimental investigation on combustion performance of cavity-strut injection of supercritical kerosene in supersonic model combustor

    Science.gov (United States)

    Sun, Ming-bo; Zhong, Zhan; Liang, Jian-han; Wang, Hong-bo

    2016-10-01

    Supersonic combustion with cavity-strut injection of supercritical kerosene in a model scramjet engine was experimentally investigated in Mach 2.92 facility with the stagnation temperatures of approximately 1430 K. Static pressure distribution in the axial direction was determined using pressure transducers installed along the centerline of the model combustor top walls. High speed imaging camera was used to capture flame luminosity and combustion region distribution. Multi-cavities were used to and stabilize the combustion in the supersonic combustor. Intrusive injection by thin struts was used to enhance the fuel-air mixing. Supercritical kerosene at temperatures of approximately 780 K and various pressures was prepared using a heat exchanger driven by the hot gas from a pre-burner and injected at equivalence ratios of approximately 1.0. In the experiments, combustor performances with different strut injection schemes were investigated and compared to direct wall injection scheme based on the measured static pressure distributions, the specific thrust increments and the images obtained by high-speed imaging camera. The experimental results showed that the injection by thin struts could obtain an enhanced mixing in the field but could not acquire a steady flame when mixing field cannot well match cavity separation region. There is no significant difference on performance between different schemes since the unsteady intermittent and oscillating flame leads to no actual combustion efficiency improvement.

  7. A model combustor for studying a reacting jet in an oscillating crossflow

    Science.gov (United States)

    Fugger, Christopher A.; Gejji, Rohan M.; Portillo, J. Enrique; Yu, Yen; Lucht, Robert P.; Anderson, William E.

    2017-06-01

    This paper discusses a novel model combustion experiment that was built for studying the structure and dynamics of a reacting jet in an unsteady crossflow. A natural-gas-fired dump combustor is used to generate and sustain an acoustically oscillating vitiated flow that serves as the crossflow for transverse jet injection. Unlike most other techniques that are limited in operating pressure or acoustic amplitude, this method of generating an unsteady flow field is demonstrated at a pressure of 10 atm with peak-to-peak oscillation amplitudes approaching 20% of the mean pressure. An optically accessible test section designed for these conditions provides access for advanced laser and optical diagnostic measurements. Detailed measurements provide insight into the complex acoustic-hydrodynamic-combustion coupling processes and offer high-quality, high-resolution validation data for numerical simulations. Careful instrumentation port design considerations for the higher amplitude acoustics are detailed. As a whole, this paper focuses on select representative segments of the experiment operational space that highlight our strategy of providing an oscillatory flowfield. This includes presenting the acoustic operational space such as acoustic amplitudes, frequencies, and mode shapes. Select imaging results are then reported to support our strategies capability to produce high-fidelity measurements.

  8. A model combustor for studying a reacting jet in an oscillating crossflow.

    Science.gov (United States)

    Fugger, Christopher A; Gejji, Rohan M; Portillo, J Enrique; Yu, Yen; Lucht, Robert P; Anderson, William E

    2017-06-01

    This paper discusses a novel model combustion experiment that was built for studying the structure and dynamics of a reacting jet in an unsteady crossflow. A natural-gas-fired dump combustor is used to generate and sustain an acoustically oscillating vitiated flow that serves as the crossflow for transverse jet injection. Unlike most other techniques that are limited in operating pressure or acoustic amplitude, this method of generating an unsteady flow field is demonstrated at a pressure of 10 atm with peak-to-peak oscillation amplitudes approaching 20% of the mean pressure. An optically accessible test section designed for these conditions provides access for advanced laser and optical diagnostic measurements. Detailed measurements provide insight into the complex acoustic-hydrodynamic-combustion coupling processes and offer high-quality, high-resolution validation data for numerical simulations. Careful instrumentation port design considerations for the higher amplitude acoustics are detailed. As a whole, this paper focuses on select representative segments of the experiment operational space that highlight our strategy of providing an oscillatory flowfield. This includes presenting the acoustic operational space such as acoustic amplitudes, frequencies, and mode shapes. Select imaging results are then reported to support our strategies capability to produce high-fidelity measurements.

  9. A Priori Analysis of a Compressible Flamelet Model using RANS Data for a Dual-Mode Scramjet Combustor

    Science.gov (United States)

    Quinlan, Jesse R.; Drozda, Tomasz G.; McDaniel, James C.; Lacaze, Guilhem; Oefelein, Joseph

    2015-01-01

    In an effort to make large eddy simulation of hydrocarbon-fueled scramjet combustors more computationally accessible using realistic chemical reaction mechanisms, a compressible flamelet/progress variable (FPV) model was proposed that extends current FPV model formulations to high-speed, compressible flows. Development of this model relied on observations garnered from an a priori analysis of the Reynolds-Averaged Navier-Stokes (RANS) data obtained for the Hypersonic International Flight Research and Experimentation (HI-FiRE) dual-mode scramjet combustor. The RANS data were obtained using a reduced chemical mechanism for the combustion of a JP-7 surrogate and were validated using avail- able experimental data. These RANS data were then post-processed to obtain, in an a priori fashion, the scalar fields corresponding to an FPV-based modeling approach. In the current work, in addition to the proposed compressible flamelet model, a standard incompressible FPV model was also considered. Several candidate progress variables were investigated for their ability to recover static temperature and major and minor product species. The effects of pressure and temperature on the tabulated progress variable source term were characterized, and model coupling terms embedded in the Reynolds- averaged Navier-Stokes equations were studied. Finally, results for the novel compressible flamelet/progress variable model were presented to demonstrate the improvement attained by modeling the effects of pressure and flamelet boundary conditions on the combustion.

  10. Improved Modeling of Finite-Rate Turbulent Combustion Processes in Research Combustors

    Science.gov (United States)

    VanOverbeke, Thomas J.

    1998-01-01

    The objective of this thesis is to further develop and test a stochastic model of turbulent combustion in recirculating flows. There is a requirement to increase the accuracy of multi-dimensional combustion predictions. As turbulence affects reaction rates, this interaction must be more accurately evaluated. In this work a more physically correct way of handling the interaction of turbulence on combustion is further developed and tested. As turbulence involves randomness, stochastic modeling is used. Averaged values such as temperature and species concentration are found by integrating the probability density function (pdf) over the range of the scalar. The model in this work does not assume the pdf type, but solves for the evolution of the pdf using the Monte Carlo solution technique. The model is further developed by including a more robust reaction solver, by using accurate thermodynamics and by more accurate transport elements. The stochastic method is used with Semi-Implicit Method for Pressure-Linked Equations. The SIMPLE method is used to solve for velocity, pressure, turbulent kinetic energy and dissipation. The pdf solver solves for temperature and species concentration. Thus, the method is partially familiar to combustor engineers. The method is compared to benchmark experimental data and baseline calculations. The baseline method was tested on isothermal flows, evaporating sprays and combusting sprays. Pdf and baseline predictions were performed for three diffusion flames and one premixed flame. The pdf method predicted lower combustion rates than the baseline method in agreement with the data, except for the premixed flame. The baseline and stochastic predictions bounded the experimental data for the premixed flame. The use of a continuous mixing model or relax to mean mixing model had little effect on the prediction of average temperature. Two grids were used in a hydrogen diffusion flame simulation. Grid density did not effect the predictions except

  11. NONEQUILIBRIUM SULFUR CAPTURE & RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR

    Energy Technology Data Exchange (ETDEWEB)

    Bert Zauderer

    2003-04-21

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. The reacted particles impact and melt in the liquid slag layer on the combustor wall by the centrifugal force of the swirling combustion gases. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Prior analyses and laboratory scale data indicated that for Coal Tech's 20 MMBtu/hour, air-cooled, slagging coal combustor slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to validate this sulfur-in-slag model in a group of combustor tests. A total of 36 days of testing on the combustor were completed during the period of performance of this project. This was more that double the 16 test days that were required in the original work statement. The extra tests were made possible by cost saving innovations that were made in the operation of the combustor test facility and in additional investment of Coal Tech resources in the test effort. The original project plan called for two groups of tests. The first group of tests involved the injection of calcium sulfate particles in the form of gypsum or plaster of Paris with the coal into the 20 MMBtu/hour-combustor. The second group of tests consisted of the entire two-step process, in which lime or limestone is co-injected with coal and reacts with the sulfur gas released during combustion to form calcium sulfate particles that impact and dissolve in the slag layer. Since this sulfur capture process has been validated in numerous prior tests in this combustor, the primary effort in the present project was on achieving the high slag flow rates needed to retain the sulfur in the slag.

  12. On the Role of Chemical Kinetics Modeling in the LES of Premixed Bluff Body and Backward-Facing Step Combustors

    KAUST Repository

    Chakroun, Nadim W.

    2017-01-05

    Recirculating flows in the wake of a bluff body, behind a sudden expansion or down-stream of a swirler, are pivotal for anchoring a flame and expanding the stability range. The size and structure of these recirculation zones and the accurate prediction of the length of these zones is a very important characteristic that computational simulations should have. Large eddy simulation (LES) techniques with an appropriate combustion model and reaction mechanism afford a balance between computational complexity and predictive accuracy. In this study, propane/air mixtures were simulated in a bluff-body stabilized combustor based on the Volvo test case and also in a backward-facing step combustor. The main goal is to investigate the role of the chemical mechanism and the accuracy of estimating the extinction strain rate on the prediction of important ow features such as recirculation zones. Two 2-step mechanisms were employed, one which gave reasonable extinction strain rates and another modi ed 2-step mechanism where it grossly over-predicted the values. This modified mechanism under-predicted recirculation zone lengths compared to the original mechanism and had worse agreement with experiments in both geometries. While the recirculation zone lengths predicted by both reduced mechanisms in the step combustor scale linearly with the extinction strain rate, the scaling curves do not match experimental results as none of the simpli ed mechanisms produce extinction strain rates that are consistent with those predicted by the comprehensive mechanisms. We conclude that it is very important that a chemical mechanism is able to correctly predict extinction strain rates if it is to be used in CFD simulations.

  13. Experimental and numerical analysis of natural bio and syngas swirl flames in a model gas turbine combustor

    Science.gov (United States)

    Iqbal, S.; Benim, A. C.; Fischer, S.; Joos, F.; Kluβ, D.; Wiedermann, A.

    2016-10-01

    Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally. In the investigation, an emphasis is placed upon the external flue gas recirculation, which is a promising technology for increasing the efficiency of the carbon capture and storage process, which, however, can change the combustion behaviour significantly. A further emphasis is placed upon the investigation of alternative fuels such as biogas and syngas in comparison to the conventional natural gas. Flames are also investigated numerically using the open source CFD software OpenFOAM. In the numerical simulations, a laminar flamelet model based on mixture fraction and reaction progress variable is adopted. As turbulence model, the SST model is used within a URANS concept. Computational results are compared with the experimental data, where a fair agreement is observed.

  14. Combustor and combustor screech mitigation methods

    Science.gov (United States)

    Kim, Kwanwoo; Johnson, Thomas Edward; Uhm, Jong Ho; Kraemer, Gilbert Otto

    2014-05-27

    The present application provides for a combustor for use with a gas turbine engine. The combustor may include a cap member and a number of fuel nozzles extending through the cap member. One or more of the fuel nozzles may be provided in a non-flush position with respect to the cap member.

  15. Experimental results showing the internal three-component velocity field and outlet temperature contours for a model gas turbine combustor

    CSIR Research Space (South Africa)

    Meyers, BC

    2011-09-01

    Full Text Available A three-component flow field inside a can-type, forward flow experimental combustor was measured under non-reacting conditions. The combustor was run at atmospheric conditions with the air flow supplied from a fan and the outlet was straight...

  16. 5 kHz thermometry in a swirl-stabilized gas turbine model combustor using chirped probe pulse femtosecond CARS. Part 1: Temporally resolved swirl-flame thermometry

    KAUST Repository

    Dennis, Claresta N.

    2016-06-20

    Single-laser-shot temperature measurements at 5 kHz were performed in a gas turbine model combustor using femtosecond (fs) coherent anti-Stokes Raman scattering (CARS). The combustor was operated at two conditions; one exhibiting a low level of thermoacoustic instability and the other a high level of instability. Measurements were performed at 73 locations within each flame in order to resolve the spatial flame structure and compare to previously published studies. The measurement procedures, including the procedure for calibrating the laser system parameters, are discussed in detail. Despite the high turbulence levels in the combustor, signals were obtained on virtually every laser shot, and these signals were strong enough for spectral fitting analysis for determination of flames temperatures. The spatial resolution of the single-laser shot temperature measurements was approximately 600 µm, the precision was approximately ±2%, and the estimated accuracy was approximately ±3%. The dynamic range was sufficient for temperature measurements ranging from 300 K to 2200 K, although some detector saturation was observed for low temperature spectra. These results demonstrate the usefulness of fs-CARS for the investigation of highly turbulent combustion phenomena. In a companion paper, the time-resolved fs CARS data are analyzed to provide insight into the temporal dynamics of the gas turbine model combustor flow field.

  17. Analytical and experimental investigations of gas turbine model combustor acoustics operated at atmospheric pressure

    Science.gov (United States)

    Richecoeur, Franck; Schuller, Thierry; Lamraoui, Ammar; Ducruix, Sébastien

    2013-01-01

    When coupled to acoustics, unsteady heat release oscillations may cause recurrent problems in many combustion chambers, potentially leading to dramatic damages to the structure. Accumulation of acoustic energy around the eigenmodes of the combustor results from the resonant coupling between pressure disturbances in the flame region with synchronized heat release rate perturbations. Predicting these frequencies and the corresponding sound pressure field is a key issue to design passive or active control systems to prevent the growth of these instabilities. In this study, an acoustically controlled combustion test bench CESAM is used to stabilize a partially premixed swirling propane-air flame. In the premixing tube, reactants are injected tangentially to generate the swirling flow, the flame being stabilized in the combustion chamber by a sudden expansion of the cross section. The premixer backplane is equipped with an Impedance Control System (ICS) allowing to adjust the acoustic reflection coefficient at this location. Acoustics of the coupled-cavity system formed by the premixer and the combustion chamber is investigated analytically by taking into account the measured acoustic impedances at the premixer backplane and in the feeding lines. The chamber length is also modified to examine the effects of the geometry on these predictions. It is shown that the premixer and combustion chamber can be considered as acoustically decoupled for small values of the acoustic coupling index, defined in the article. This offers flexible solutions to control the pressure distribution within the combustor, except when these frequencies match. When the frequencies are close to each other, only the analysis of the damping of the different cavities enables to indicate whether the system is coupled or not. Modifying either the acoustic coupling index or the damping values featuring the same frequency appears then as alternative solutions to decouple cavities.

  18. In-situ laser spectroscopy of CO, Ch4, and H2O in a particle laden laboratory-scale fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Lackner Maximilian

    2002-01-01

    Full Text Available The pyrolysis, devolatilization and char combustion of bituminous coal and biomass (beechwood, firwood were investigated in a laboratory-scale fluidized bed combustor by tunable diode laser spectroscopy. Individual fuel particles were suspended in the freeboard of the unit. The bed temperature was 800 °C, the oxygen partial pressure 0 to 20 kPa (0-10 vol.%. Two Fabry Perot type tunable near infrared diode lasers were deployed for quantitative in-situ species concentration measurements. CH4 and CO were measured simultaneously during devolatilization and char combustion in-situ 10 mm above the surface of the fuel particles as well as H2O using laser spectroscopy. Sand particles were passing the probing laser beam path. Besides the resonant absorption of the laser light by CO, CH4 and H2O severe and strongly transient non-resonant attenuation by partial blocking of the beam and beam steering effects occurred. By wavelength tuning the two laser sources, species concentrations could be determined. The measured absorbances had to be corrected for the real temperature measured at the position of the probing laser beam. In addition, CO, CO2 and O2 were determined ex-situ by con ventional methods. A spatial profile inside the FBC of major species (CH4, CO, CO2, O, H, OH was calculated using a chemical kinetics program for a single fuel particle in a plug flow reactor geometry. The results were compared to the experimental findings. Good agreement was found. Tunable diode laser spectroscopy was found to be an apt method of determining quantitative species concentrations of multiple gases in a high temperature multi phase environment.

  19. An experimental study of interacting swirl flows in a model gas turbine combustor

    Science.gov (United States)

    Vishwanath, Rahul B.; Tilak, Paidipati Mallikarjuna; Chaudhuri, Swetaprovo

    2018-03-01

    In this experimental work, we analyze the flow structures emerging from the mutual interaction between adjacent swirling flows at variable degrees of swirl, issued into a semi-confined chamber, as it could happen in a three cup sector of an annular premixed combustor of a modern gas turbine engine. Stereoscopic particle image velocimetry ( sPIV) is used to characterize both the non-reacting and reacting flow fields in the central diametrical (vertical) plane of the swirlers and the corresponding transverse (horizontal) planes at different heights above the swirlers. A central swirling flow with a fixed swirl vane angle is allowed to interact with its neighboring flows of varied swirl levels, with constant inlet bulk flow velocity through the central port. It is found that the presence of straight jets with zero swirl or co-rotating swirling jets with increasing swirl on both sides of the central swirling jet, significantly alters its structures. As such, an increase in the amount of swirl in the neighboring flows increases the recirculation levels in central swirling flow leading to a bubble-type vortex breakdown, not formed otherwise. It is shown with the aid of Helmholtz decomposition that the transition from conical to bubble-type breakdown is captured well by the radial momentum induced by the azimuthal vorticity. Simultaneous sPIV and OH-planar laser-induced fluorescence (PLIF) are employed to identify the influence of the neighboring jets on the reacting vortex breakdown states. Significant changes in the vortex breakdown size and structure are observed due to variation in swirl levels of the neighboring jets alongside reaction and concomitant flow dilatation.

  20. Variable volume combustor

    Science.gov (United States)

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  1. Electrically charged small soot particles in the exhaust of an aircraft gas-turbine engine combustor: comparison of model and experiment

    Science.gov (United States)

    Sorokin, A.; Arnold, F.

    The emission of electrically charged soot particles by an aircraft gas-turbine combustor is investigated using a theoretical model. Particular emphasis is placed on the influence of the fuel sulfur content (FSC). The model considers the production of primary "combustion" electrons and ions in the flame zone and their following interaction with molecular oxygen, sulfur-bearing molecules (e.g. O 2, SO 2, SO 3, etc.) and soot particles. The soot particle size distribution is approximated by two different populations of mono-dispersed large and small soot particles with diameters of 20-30 and 5-7 nm, respectively. The effect of thermal ionization of soot and its interaction with electrons and positive and negative ions is included in the model. The computed positive and negative chemiion (CI) concentrations at the combustor exit and relative fractions of small neutral and charged soot particles were found to be in satisfactory agreement with experimental data. The results show that the FSC indeed may influence the concentration of negative CI at low fuel flow into combustor. Importantly the simulation indicates a very efficient mutual interaction of electrons and ions with soot particles with a large effect on both ion and charged soot particle concentrations. This result may be interpreted as a possible indirect effect of FSC on the growth and size distribution of soot particles.

  2. Wall temperature measurements at elevated pressures and high temperatures in sooting flames in a gas turbine model combustor

    Science.gov (United States)

    Nau, Patrick; Yin, Zhiyao; Geigle, Klaus Peter; Meier, Wolfgang

    2017-12-01

    Wall temperatures were measured with thermographic phosphors on the quartz walls of a model combustor in ethylene/air swirl flames at 3 bar. Three operating conditions were investigated with different stoichiometries and with or without additional injection of oxidation air downstream of the primary combustion zone. YAG:Eu and YAG:Dy were used to cover a total temperature range of 1000-1800 K. Measurements were challenging due to the high thermal background from soot and window degradation at high temperatures. The heat flux through the windows was estimated from the temperature gradient between the in- and outside of the windows. Differences in temperature and heat flux density profiles for the investigated cases can be explained very well with the previously measured differences in flame temperatures and flame shapes. The heat loss relative to thermal load is quite similar for all investigated flames (15-16%). The results complement previous measurements in these flames to investigate soot formation and oxidation. It is expected, that the data set is a valuable input for numerical simulations of these flames.

  3. Dual-Mode Combustor

    Science.gov (United States)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  4. A simplified model of nitric oxide emission from a circulating fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, J.; Basu, P. [Technical University of Nova Scotia, Halifax, NS (Canada)

    1995-10-01

    A simplified mathematical model leading to a closed form of solution is developed for estimation of nitric oxide emission from a coal fired circulating fluidized bed (CFB) furnace. The furnace is divided into two sections: a lower section below and an upper section above the secondary air injection level. Reactions in the cyclone and the return leg are neglected. Furnace dimensions, coal feed rate, coal composition and furnace temperature are inputs to the model which was validated against several pilot scale and commercial units. Experimental results from two pilot plants and two commercial power plants agree with model predictions. A sensitivity analysis was carried out using the model to examine the effect of different operating parameters and coal properties on the overall NO emission from the furnace. It was found that excess air and furnace temperature are most important factors influencing the NO emission level. The primary to secondary air ratio influences the NO emission level reasonably. Properties of coal are other factors which affect the NO emission to a large extent. The model, though it involves some simplification, predicts the overall emission of NO with a level of accuracy accepted in commercial operation. 27 refs., 8 figs., 2 tabs.

  5. Steam reformer with catalytic combustor

    Science.gov (United States)

    Voecks, Gerald E. (Inventor)

    1990-01-01

    A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

  6. Effects of background noises on nonlinear dynamics of a modelled thermoacoustic combustor.

    Science.gov (United States)

    Li, Xinyan; Zhao, Dan; Li, Xuan

    2018-01-01

    In this work, the effects of background noises on nonlinear dynamics of a modelled standing-wave thermoacoustic system with subcritical Hopf bifurcation behaviors are studied. These noises include (1) pressure-coupled (acoustic), (2) velocity-coupled (flow), and (3) external combustion noise. It is found that these three types of background noises play important, but different roles in changing the hysteresis width and stability boundary. In addition, the stochastic transition from stability to instability is investigated, as the noise intensity is varied. Two different stochastic P-bifurcations are identified. One is related to a craterlike probability density distribution. The other is associated with a probability density distribution characterized with two peaks and one trough. With each type of noise affecting the system's stochastic behaviors being evaluated, the effect of two different types of noises is then studied. It is shown that the combined noises (types 1 and 2) cannot only destabilize global stable thermoacoustic system, but also stabilize linearly unstable system. This depends strongly on the superimposition form of the two types of noises. In addition, when the thermoacoustic system is disturbed by the combined noise (types 3 and 1 or types 3 and 2), the transition process is dominated by the combustion noise.

  7. Geoacoustic Physical Model Fabrication Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Fabricates three-dimensional rough surfaces (e.g., fractals, ripples) out of materials such as PVC or wax to simulate the roughness properties associated...

  8. Combustion of biomass-derived, low caloric value, fuel gas in a gasturbine combustor

    Energy Technology Data Exchange (ETDEWEB)

    Andries, J.; Hoppesteyn, P.D.J.; Hein, K.R.G. [Technische Univ. Delf (Netherlands)

    1998-09-01

    The use of biomass and biomass/coal mixtures to produce electricity and heat reduces the net emissions of CO{sub 2}, contributes to the restructuring of the agricultural sector, helps to reduce the waste problem and saves finite fossil fuel reserves. Pressurised fluidised bed gasification followed by an adequate gas cleaning system, a gas turbine and a steam turbine, is a potential attractive way to convert biomass and biomass/coal mixtures. To develop and validate mathematical models, which can be used to design and operate Biomass-fired Integrated Gasification Combined Cycle (BIGCC) systems, a Process Development Unit (PPDU) with a maximum thermal capacity of 1.5 MW{sub th}, located at the Laboratory for Thermal Power Engineering of the Delft University of Technology in The Netherlands is being used. The combustor forms an integral part of this facility. Recirculated flue gas is used to cool the wall of the combustor. (orig.)

  9. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    W. R. Laster; E. Anoshkina

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy's National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1 - Implementation Plan, Phase 2 - Validation Testing and Phase 3 - Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  10. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Laster, W. R.; Anoshkina, E.

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy’s National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1- Implementation Plan, Phase 2- Validation Testing and Phase 3 – Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  11. Active Combustion Control for Aircraft Gas-Turbine Engines-Experimental Results for an Advanced, Low-Emissions Combustor Prototype

    Science.gov (United States)

    DeLaat, John C.; Kopasakis, George; Saus, Joseph R.; Chang, Clarence T.; Wey, Changlie

    2012-01-01

    Lean combustion concepts for aircraft engine combustors are prone to combustion instabilities. Mitigation of instabilities is an enabling technology for these low-emissions combustors. NASA Glenn Research Center s prior activity has demonstrated active control to suppress a high-frequency combustion instability in a combustor rig designed to emulate an actual aircraft engine instability experience with a conventional, rich-front-end combustor. The current effort is developing further understanding of the problem specifically as applied to future lean-burning, very low-emissions combustors. A prototype advanced, low-emissions aircraft engine combustor with a combustion instability has been identified and previous work has characterized the dynamic behavior of that combustor prototype. The combustor exhibits thermoacoustic instabilities that are related to increasing fuel flow and that potentially prevent full-power operation. A simplified, non-linear oscillator model and a more physics-based sectored 1-D dynamic model have been developed to capture the combustor prototype s instability behavior. Utilizing these models, the NASA Adaptive Sliding Phasor Average Control (ASPAC) instability control method has been updated for the low-emissions combustor prototype. Active combustion instability suppression using the ASPAC control method has been demonstrated experimentally with this combustor prototype in a NASA combustion test cell operating at engine pressures, temperatures, and flows. A high-frequency fuel valve was utilized to perturb the combustor fuel flow. Successful instability suppression was shown using a dynamic pressure sensor in the combustor for controller feedback. Instability control was also shown with a pressure feedback sensor in the lower temperature region upstream of the combustor. It was also demonstrated that the controller can prevent the instability from occurring while combustor operation was transitioning from a stable, low-power condition to

  12. Thermal Fluid Analysis of the Combustor Test Setup for a US Army Research Laboratory (ARL) Liquid-Fueled Thermophotovoltaic Power Source Demonstrator

    Science.gov (United States)

    2015-09-01

    500 °C.1 Figure 1 describes the primary components of a TPV system : a heat source, an emitter, and a photovoltaic converter. The heat source...Research Laboratory (ARL) is combustion-based thermophotovoltaic (TPV) power sources. Combustion can be used to convert fuel to heat a surface to...8 Properties of the user-defined Inconel 6004 ...........................................7 Fig. 9 Specific heat vs. temperature for the user

  13. Advances in measurements and simulation of gas-particle flows and coal combustion in burners/combustors

    International Nuclear Information System (INIS)

    Zhou, L X

    2009-01-01

    Innovative coal combustors were developed, and measurement and simulation of gas-particle flows and coal combustion in such combustors were done in the Department of Engineering Mechanics, Tsinghua University. LDV/PDPA measurements are made to understand the behavior of turbulent gas-particle flows in coal combustors. Coal combustion test was done for the non-slagging cyclone coal combustor. The full two-fluid model developed by the present author was used to simulate turbulent gas-particle flows, coal combustion and NO x formation. It is found by measurements and simulation that the optimum design can give large-size recirculation zones for improving the combustion performance for all the combustors. The combustion test shows that the nonslagging coal combustor can burn 3-5mm coal particles with good combustion efficiency and low NO emission. Simulation in comparison with experiments indicates that the swirl number can significantly affect the NO formation in the swirl coal combustor.

  14. Energy laboratory data and model directory

    Science.gov (United States)

    Lahiri, S.; Carson, J.

    1981-07-01

    Over the past several years M.I.T. faculty, staff, and students have produced a substantial body of research and analysis relating to the production, conversion,, and use of energy in domestic and international markets. Much of this research takes the form of models and associated data bases that have enduring value in policy studies (models) and in supporting related research and modeling efforts (date). For such models and data it is important to ensure that the useful life cycle does not end with the conclusion of the research project. This directory is an important step in extending the usefulness of models and data bases available at the M.I.T. Energy Laboratory. It will be updated from time to time to include new models and data bases that have been developed, or significant changes that have occurred.

  15. Micro-mixer/combustor

    KAUST Repository

    Badra, Jihad Ahmad

    2014-09-18

    A micro-mixer/combustor to mix fuel and oxidant streams into combustible mixtures where flames resulting from combustion of the mixture can be sustained inside its combustion chamber is provided. The present design is particularly suitable for diffusion flames. In various aspects the present design mixes the fuel and oxidant streams prior to entering a combustion chamber. The combustion chamber is designed to prevent excess pressure to build up within the combustion chamber, which build up can cause instabilities in the flame. A restriction in the inlet to the combustion chamber from the mixing chamber forces the incoming streams to converge while introducing minor pressure drop. In one or more aspects, heat from combustion products exhausted from the combustion chamber may be used to provide heat to at least one of fuel passing through the fuel inlet channel, oxidant passing through the oxidant inlet channel, the mixing chamber, or the combustion chamber. In one or more aspects, an ignition strip may be positioned in the combustion chamber to sustain a flame without preheating.

  16. Combustor and method for distributing fuel in the combustor

    Science.gov (United States)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; York, William David

    2016-04-26

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface. A plurality of tubes extends from the upstream surface through the downstream surface, and each tube provides fluid communication through the tube bundle. A baffle extends axially inside the tube bundle between adjacent tubes. A method for distributing fuel in a combustor includes flowing a fuel into a fuel plenum defined at least in part by an upstream surface, a downstream surface, a shroud, and a plurality of tubes that extend from the upstream surface to the downstream surface. The method further includes impinging the fuel against a baffle that extends axially inside the fuel plenum between adjacent tubes.

  17. Laboratory constraints on models of earthquake recurrence

    Science.gov (United States)

    Beeler, Nicholas M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian D.; Goldsby, David L.

    2014-01-01

    In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip rate-dependent process that also determines the size of the stress drop [Dieterich, 1979; Ruina, 1983] and as a consequence, stress drop varies weakly but systematically with loading rate [e.g., Gu and Wong, 1991; Karner and Marone, 2000; McLaskey et al., 2012]. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. As follows from the previous studies referred to above, experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a non-linear slip-predictable model. The fault’s rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence co-vary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability and successive stress drops are strongly correlated indicating a ‘memory’ of prior slip history that extends over at least one recurrence cycle.

  18. Non-linear dynamics in pulse combustor: A review

    Indian Academy of Sciences (India)

    the regime of periodic behaviour, and (iii) using the dynamic characteristics to predict events like extinction. 2. Dynamic characterization using mathematical model. Pulse combustor consists of a combustion chamber that is often modelled as a well- stirred reactor due to intense mixing with a tailpipe extending from one end.

  19. Coal desulfurization in a rotary kiln combustor

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, J.T. Jr.

    1990-08-15

    BCR National Laboratory (BCRNL) has initiated a project aimed at evaluating the technical and economic feasibility of using a rotary kiln, suitably modified, to burn Pennsylvania anthracite wastes, co-fired with high-sulfur bituminous coal. Limestone will be injected into the kiln for sulfur control, to determine whether high sulfur capture levels can be achieved with high sorbent utilization. The principal objectives of this work are: (1) to prove the feasibility of burning anthracite refuse, with co-firing of high-sulfur bituminous coal and with limestone injection for sulfur emissions control, in a rotary kiln fitted with a Universal Energy International (UEI) air injector system; (2) to determine the emissions levels of SO{sub x} and NO{sub x} and specifically to identify the Ca/S ratios that are required to meet New Source Performance Standards; (3) to evaluate the technical and economic merits of a commercial rotary kiln combustor in comparison to fluidized bed combustors; and, (4) to ascertain the need for further work, including additional combustion tests, prior to commercial application, and to recommend accordingly a detailed program towards this end.

  20. Software Engineering Laboratory (SEL) cleanroom process model

    Science.gov (United States)

    Green, Scott; Basili, Victor; Godfrey, Sally; Mcgarry, Frank; Pajerski, Rose; Waligora, Sharon

    1991-01-01

    The Software Engineering Laboratory (SEL) cleanroom process model is described. The term 'cleanroom' originates in the integrated circuit (IC) production process, where IC's are assembled in dust free 'clean rooms' to prevent the destructive effects of dust. When applying the clean room methodology to the development of software systems, the primary focus is on software defect prevention rather than defect removal. The model is based on data and analysis from previous cleanroom efforts within the SEL and is tailored to serve as a guideline in applying the methodology to future production software efforts. The phases that are part of the process model life cycle from the delivery of requirements to the start of acceptance testing are described. For each defined phase, a set of specific activities is discussed, and the appropriate data flow is described. Pertinent managerial issues, key similarities and differences between the SEL's cleanroom process model and the standard development approach used on SEL projects, and significant lessons learned from prior cleanroom projects are presented. It is intended that the process model described here will be further tailored as additional SEL cleanroom projects are analyzed.

  1. Effect of ramp-cavity on hydrogen fueled scramjet combustor

    Directory of Open Access Journals (Sweden)

    J.V.S. Moorthy

    2014-03-01

    Full Text Available Sustained combustion and optimization of combustor are the two challenges being faced by combustion scientists working in the area of supersonic combustion. Thorough mixing, lower stagnation pressure losses, positive thrust and sustained combustion are the key issues in the field of supersonic combustion. Special fluid mechanism is required to achieve good mixing. To induce such mechanisms in supersonic inflows, the fuel injectors should be critically shaped incurring less flow losses. Present investigations are focused on the effect of fuel injection scheme on a model scramjet combustor performance. Ramps at supersonic flow generate axial vortices that help in macro-mixing of fuel with air. Interaction of shocks generated by ramps with the fuel stream generates boro-clinic torque at the air & liquid fuel interface, enhancing micro-mixing. Recirculation zones present in cavities increase the residence time of the combustible mixture. Making use of the advantageous features of both, a ramp-cavity combustor is designed. The combustor has two sections. First, constant height section consists of a backward facing step followed by ramps and cavities on both the top and bottom walls. The ramps are located alternately on top and bottom walls. The complete combustor width is utilized for the cavities. The second section of the combustor is diverging area section. This is provided to avoid thermal choking. In the present work gaseous hydrogen is considered as fuel. This study was mainly focused on the mixing characteristics of four different fuel injection locations. It was found that injecting fuel upstream of the ramp was beneficial from fuel spread point of view.

  2. Multiscale Software Tool for Controls Prototyping in Supersonic Combustors

    National Research Council Canada - National Science Library

    Pindera, M

    2004-01-01

    .... In Phase I we have developed a proof-of-concept version of such a tool. We have developed a model-free direct control strategy with on-line training and demonstrated its capabilities in controlling isolator unstart in a hypersonic combustor...

  3. Combustion of Syngas Fuel in Gas Turbine Can Combustor

    Directory of Open Access Journals (Sweden)

    Chaouki Ghenai

    2010-01-01

    Full Text Available Numerical investigation of the combustion of syngas fuel mixture in gas turbine can combustor is presented in this paper. The objective is to understand the impact of the variability in the alternative fuel composition and heating value on combustion performance and emissions. The gas turbine can combustor is designed to burn the fuel efficiently, reduce the emissions, and lower the wall temperature. Syngas mixtures with different fuel compositions are produced through different coal and biomass gasification process technologies. The composition of the fuel burned in can combustor was changed from natural gas (methane to syngas fuel with hydrogen to carbon monoxide (H2/CO volume ratio ranging from 0.63 to 2.36. The mathematical models used for syngas fuel combustion consist of the k-ε model for turbulent flow, mixture fractions/PDF model for nonpremixed gas combustion, and P-1 radiation model. The effect of syngas fuel composition and lower heating value on the flame shape, gas temperature, mass of carbon dioxide (CO2 and nitrogen oxides (NOx per unit of energy generation is presented in this paper. The results obtained in this study show the change in gas turbine can combustor performance with the same power generation when natural gas or methane fuel is replaced by syngas fuels.

  4. Evaluation of a Liquid-Fueled Pulse Detonation Engine Combustor

    National Research Council Canada - National Science Library

    Forster, David

    1998-01-01

    ... for use in the combustor. The chosen atomizer was installed in the combustor geometries and then analyzed over a range of combustor conditions to measure deflagration to detonation transition (DDT...

  5. Aviation Shipboard Operations Modeling and Simulation (ASOMS) Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose:It is the mission of the Aviation Shipboard Operations Modeling and Simulation (ASOMS) Laboratory to provide a means by which to virtually duplicate products...

  6. Hydrogen injection scheme influence on flow structure in supersonic combustor of constant cross-section

    Science.gov (United States)

    Starov, A. V.; Goldfeld, M. A.

    2017-10-01

    The efficiency of using two variants of hydrogen injection (distributed and non-distributed injection from vertical pylons) is experimentally investigated. The tests are performed in the attached pipeline regime with the Mach number at the model combustor entrance M=2. The combustion chamber has a backward-facing step at the entrance and slotted channels for combustion stabilization. The tested variants of injection differ basically by the shapes of the fuel jets and, correspondingly, by the hydrogen distribution over the combustor. As a result, distributed injection is found to provide faster ignition, upstream displacement of the elevated pressure region, and more intense combustion over the entire combustor volume.

  7. DLE combustor exceeds performance guarantees

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, John; Leonard, Gary [GE Marine and Industrial Engines, Evendale, OH (United States)

    1995-05-01

    The 50MW Gent power station in Belgium started operating in 1994 using General Electric`s high efficiency LM6000 gas turbine. This article describes performance testing of the new Dry Low Emissions (DLE) combustion system fitted to the aeroderivative gas turbine, which has allowed the combined cycle, cogeneration facility to function at full-power, with low emissions of nitrogen oxides, carbon monoxide, and unburned hydrocarbons. Conventional combustion systems are compared to the new premixed lean combustor used here. (UK)

  8. Experimental and Computational Study of Trapped Vortex Combustor Sector Rig with High-Speed Diffuser Flow

    Directory of Open Access Journals (Sweden)

    R. C. Hendricks

    2001-01-01

    Full Text Available The Trapped Vortex Combustor (TVC potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO performance. Computational fluid dynamics (CFD simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

  9. Maximising mentorship: Variations in laboratory mentorship models implemented in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Phoebe Nzombe

    2014-11-01

    Full Text Available Background: Laboratory mentorship has proven to be an effective tool in building capacity and assisting laboratories in establishing quality management systems. The Zimbabwean Ministry of Health and Child Welfare implemented four mentorship models in 19 laboratories in conjunction with the Strengthening Laboratory Management Toward Accreditation (SLMTA programme. Objectives: This study outlines how the different models were implemented, cost involved per model and results achieved. Methods: Eleven of the laboratories had been trained previously in SLMTA (Cohort I. They were assigned to one of three mentorship models based on programmatic considerations: Laboratory Manager Mentorship (Model 1, four laboratories; One Week per Month Mentorship (Model 2, four laboratories; and Cyclical Embedded Mentorship (Model 3, three laboratories. The remaining eight laboratories (Cohort II were enrolled in Cyclical Embedded Mentorship incorporated with SLMTA training (Model 4. Progress was evaluated using a standardised audit checklist. Results: At SLMTA baseline, Model 1–3 laboratories had a median score of 30%. After SLMTA, at mentorship baseline, they had a median score of 54%. At the post-mentorship audit they reached a median score of 75%. Each of the three mentorship models for Cohort I had similar median improvements from pre- to post-mentorship (17 percentage points for Model 1, 23 for Model 2 and 25 for Model 3; p > 0.10 for each comparison. The eight Model 4 laboratories had a median baseline score of 24%; after mentorship, their median score increased to 63%. Median improvements from pre-SLMTA to post-mentorship were similar for all four models. Conclusion: Several mentorship models can be considered by countries depending on the available resources for their accreditation implementation plan.

  10. A professional development model for medical laboratory scientists working in the microbiology laboratory.

    Science.gov (United States)

    Amerson, Megan H; Pulido, Lila; Garza, Melinda N; Ali, Faheem A; Greenhill, Brandy; Einspahr, Christopher L; Yarsa, Joseph; Sood, Pramilla K; Hu, Peter C

    2012-01-01

    The University of Texas M.D. Anderson Cancer Center, Division of Pathology and Laboratory Medicine is committed to providing the best pathology and medicine through: state-of-the art techniques, progressive ground-breaking research, education and training for the clinical diagnosis and research of cancer and related diseases. After surveying the laboratory staff and other hospital professionals, the Department administrators and Human Resource generalists developed a professional development model for Microbiology to support laboratory skills, behavior, certification, and continual education within its staff. This model sets high standards for the laboratory professionals to allow the labs to work at their fullest potential; it provides organization to training technologists based on complete laboratory needs instead of training technologists in individual areas in which more training is required if the laboratory needs them to work in other areas. This model is a working example for all microbiology based laboratories who want to set high standards and want their staff to be acknowledged for demonstrated excellence and professional development in the laboratory. The PDM model is designed to focus on the needs of the laboratory as well as the laboratory professionals.

  11. The total laboratory solution: a new laboratory E-business model based on a vertical laboratory meta-network.

    Science.gov (United States)

    Friedman, B A

    2001-08-01

    Major forces are now reshaping all businesses on a global basis, including the healthcare and clinical laboratory industries. One of the major forces at work is information technology (IT), which now provides the opportunity to create a new economic and business model for the clinical laboratory industry based on the creation of an integrated vertical meta-network, referred to here as the "total laboratory solution" (TLS). Participants at the most basic level of such a network would include a hospital-based laboratory, a reference laboratory, a laboratory information system/application service provider/laboratory portal vendor, an in vitro diagnostic manufacturer, and a pharmaceutical/biotechnology manufacturer. It is suggested that each of these participants would add value to the network primarily in its area of core competency. Subvariants of such a network have evolved over recent years, but a TLS comprising all or most of these participants does not exist at this time. Although the TLS, enabled by IT and closely akin to the various e-businesses that are now taking shape, offers many advantages from a theoretical perspective over the current laboratory business model, its success will depend largely on (a) market forces, (b) how the collaborative networks are organized and managed, and (c) whether the network can offer healthcare organizations higher quality testing services at lower cost. If the concept is successful, new demands will be placed on hospital-based laboratory professionals to shift the range of professional services that they offer toward clinical consulting, integration of laboratory information from multiple sources, and laboratory information management. These information management and integration tasks can only increase in complexity in the future as new genomic and proteomics testing modalities are developed and come on-line in clinical laboratories.

  12. A Design Methodology for Rapid Implementation of Active Control Systems Across Lean Direct Injection Combustor Platforms

    Science.gov (United States)

    Baumann, William T.; Saunders, William R.; Vandsburger, Uri; Saus, Joseph (Technical Monitor)

    2003-01-01

    The VACCG team is comprised of engineers at Virginia Tech who specialize in the subject areas of combustion physics, chemical kinetics, dynamics and controls, and signal processing. Currently, the team's work on this NRA research grant is designed to determine key factors that influence combustion control performance through a blend of theoretical and experimental investigations targeting design and demonstration of active control for three different combustors. To validiate the accuracy of conclusions about control effectiveness, a sequence of experimental verifications on increasingly complex lean, direct injection combustors is underway. During the work period January 1, 2002 through October 15, 2002, work has focused on two different laboratory-scale combustors that allow access for a wide variety of measurements. As the grant work proceeds, one key goal will be to obtain certain knowledge about a particular combustor process using a minimum of sophisticated measurements, due to the practical limitations of measurements on full-scale combustors. In the second year, results obtained in the first year will be validated on test combustors to be identified in the first quarter of that year. In the third year, it is proposed to validate the results at more realistic pressure and power levels by utilizing the facilities at the Glenn Research Center.

  13. Flame stabilization and mixing characteristics in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Bobba, Mohan K.

    A novel combustor design, referred to as the Stagnation Point Reverse-Flow (SPRF) combustor, was recently developed that is able to operate stably at very lean fuel-air mixtures and with low NOx emissions even when the fuel and air are not premixed before entering the combustor. The primary objective of this work is to elucidate the underlying physics behind the excellent stability and emissions performance of the SPRF combustor. The approach is to experimentally characterize velocities, species mixing, heat release and flame structure in an atmospheric pressure SPRF combustor with the help of various optical diagnostic techniques: OH PLIF, chemiluminescence imaging, PIV and Spontaneous Raman Scattering. Results indicate that the combustor is primarily stabilized in a region downstream of the injector that is characterized by low average velocities and high turbulence levels; this is also the region where most of the heat release occurs. High turbulence levels in the shear layer lead to increased product entrainment levels, elevating the reaction rates and thereby enhancing the combustor stability. The effect of product entrainment on chemical timescales and the flame structure is illustrated with simple reactor models. Although reactants are found to burn in a highly preheated (1300 K) and turbulent environment due to mixing with hot product gases, the residence times are sufficiently long compared to the ignition timescales such that the reactants do not autoignite. Turbulent flame structure analysis indicates that the flame is primarily in the thin reaction zones regime throughout the combustor, and it tends to become more flamelet like with increasing distance from the injector. Fuel-air mixing measurements in case of non-premixed operation indicate that the fuel is shielded from hot products until it is fully mixed with air, providing nearly premixed performance without the safety issues associated with premixing. The reduction in NOx emissions in the SPRF

  14. Optical measurements of soot size and number density in a complex flow, swirl-stabilized combustor

    Science.gov (United States)

    Samuelsen, G. S.; Wood, C. P.; Jackson, T. A.

    1984-01-01

    In-flame optical measurements of soot particulates in a turbulent, recirculating (i.e., complex flow) model laboratory combustor are described. A nonintrusive optical probe based on large angle (60 deg, 20 deg) intensity ratio scattering was used to yield a point measurement of particulate in the size range of 0.08 to 0.38 micrometers. The performance of the optical technique was evaluated, and an exploratory assessment of the spatial distribution of soot was conducted with attention to fuel molecular structure, fuel loading, and a smoke-suppressant additive (ferrocene). Isooctane and mixtures of isooctane with various ring and aromatic compounds blended to yield the smoke point of a JP-8 stock were prevaporized and introduced through a hollow cone nozzle. The addition of ring compounds to the base isooctane substantially changed the distribution of soot and increased the overall emission by 300%. The production of soot was substantially reduced by a decrease in fuel loading, and marginally reduced or not affected by the additive depending on fuel structure. The optical technique is a potentially powerful tool for providing the experimental evidence necessary to understand the processes of soot formation and burnout in complex flows typical of gas turbine combustors. However, scanning electron micrographs of extracted sample established that the technique is limited to the large particle wing of the soot size distribution, and optical and electronic processing can induce biasing and uncertainties which must be understood and controlled before the potential of the technique can be fulfilled.

  15. Experimental investigation and mathematical modelling of the combustion of brown coal, refuse and mixed fuels in a circulating fluidized bed combustor; Experimentelle Untersuchung und mathematische Modellierung der Verbrennung von Braunkohle, Abfallstoffen und Mischbrennstoffen in einer zirkulierenden Wirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Brunne, T.; Hiller, A. [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik; Albrecht, J. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany); Quang, N. [Polytechnic Inst., Danang (Viet Nam)

    1998-09-01

    Extensive experiments on combustion of biological materials and residues in fluidized bed combustors and dust combustors have been carried out at the Department of Power Plant Engineering of Dresden University since the early nineties. Particular interest was taken in mixing brown coal with sewage sludge, sugar pulp and waste wood. The experiments were supplemented by modelling in a research project funded jointly by the BMBF and Messrs. Lurgi since early 1997. A combustion cell model designed by Siegen University is being modified for the new mixed fuels, and preliminary investigations were carried out on a batch reactor while the modelling work was continued. (orig.) [Deutsch] An dem Lehrstuhl fuer Kraftwerkstechnik der TU Dresden werden seit Anfang der 90-iger Jahre umfangreiche experimentelle Untersuchungen zur Verbrennung von Bio- und Reststoffen in Wirbelschicht- und Staubfeuerungen durchgefuehrt. Dabei war vor allem die Zufeuerung dieser Stoffe in Waermeerzeugeranlagen auf Braunkohlenbasis von besonderem Interesse. Experimentell konnte nachgewiesen werden, dass sowohl Biobrennstoffe als auch Abfaelle in zirkulierenden Wirbelschichtfeuerungen umweltschonend zur Waermeerzeugung eingesetzt werden koennen. Als Beispiel wird das an Hand von Braunkohle-Klaerschlammgemischen sowie Bagasse- und Holz-Braunkohlegemischen gezeigt. Neben den experimentellen Untersuchungen bietet die Modellierung der Verbrennungsvorgaenge ein geeignetes Mittel um Voraussagen zu anderen Mischungsanteilen sowie anderen geometrischen Abmessungen machen zu koennen. Seit Anfang 1997 wird dazu ein vom BMBF und der Firma Lurgi gefoerdertes Forschungsvorhaben bearbeitet. Ein von der Universitaet Gesamthochschule Siegen fuer die Braunkohleverbrennung konzipiertes Zellenmodell wird auf die neuen Brennstoffgemische erweitert. Da grundsaetzlich andere Stoffzusammensetzungen vorliegen, wurden an einem Batch-Reaktor Voruntersuchungen zum Pyrolyseverhalten der Brennstoffe durchgefuehrt. Erste

  16. An Integrated Biochemistry Laboratory, Including Molecular Modeling

    Science.gov (United States)

    Hall, Adele J. Wolfson Mona L.; Branham, Thomas R.

    1996-11-01

    ) experience with methods of protein purification; (iii) incorporation of appropriate controls into experiments; (iv) use of basic statistics in data analysis; (v) writing papers and grant proposals in accepted scientific style; (vi) peer review; (vii) oral presentation of results and proposals; and (viii) introduction to molecular modeling. Figure 1 illustrates the modular nature of the lab curriculum. Elements from each of the exercises can be separated and treated as stand-alone exercises, or combined into short or long projects. We have been able to offer the opportunity to use sophisticated molecular modeling in the final module through funding from an NSF-ILI grant. However, many of the benefits of the research proposal can be achieved with other computer programs, or even by literature survey alone. Figure 1.Design of project-based biochemistry laboratory. Modules (projects, or portions of projects) are indicated as boxes. Each of these can be treated independently, or used as part of a larger project. Solid lines indicate some suggested paths from one module to the next. The skills and knowledge required for protein purification and design are developed in three units: (i) an introduction to critical assays needed to monitor degree of purification, including an evaluation of assay parameters; (ii) partial purification by ion-exchange techniques; and (iii) preparation of a grant proposal on protein design by mutagenesis. Brief descriptions of each of these units follow, with experimental details of each project at the end of this paper. Assays for Lysozyme Activity and Protein Concentration (4 weeks) The assays mastered during the first unit are a necessary tool for determining the purity of the enzyme during the second unit on purification by ion exchange. These assays allow an introduction to the concept of specific activity (units of enzyme activity per milligram of total protein) as a measure of purity. In this first sequence, students learn a turbidimetric assay

  17. Experimental study on the heavy-duty gas turbine combustor

    International Nuclear Information System (INIS)

    Antonovsky, V.; Ahn, Kook Young

    2000-01-01

    The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed in the scale 1:1. The model experiments were executed at a pressure smaller than in the real gas turbine. The combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure, and NOx emission were measured at partial and full load for both model and on-site testing. The comparison of these items of information, received on similar modes in the stand and field tests, has allowed the development of a method of calculation and the improvement of gas turbine combustors

  18. Comparison of empirical models and laboratory saturated hydraulic ...

    African Journals Online (AJOL)

    Numerous methods for estimating soil saturated hydraulic conductivity exist, which range from direct measurement in the laboratory to models that use only basic soil properties. A study was conducted to compare laboratory saturated hydraulic conductivity (Ksat) measurement and that estimated from empirical models.

  19. A smart model for clinical laboratory personnel development.

    Science.gov (United States)

    Sirisali, Kulnaree; Manochiopinij, Sudarat; Leelahakul, Pairoj; Vattanaviboon, Phantip; Wonglumsom, Wijit; Sirisali, Sophon

    2010-11-01

    To become a quality clinical laboratory, personnel development is the most important factor. In order to achieve this goal, it should emphasize that clinical laboratory is not only a testing laboratory; it must be a knowledge-based service laboratory. A smart model for clinical laboratory personnel development under the Human Asset Development (HAD) program had been launched since 2003. To strengthen the competency of clinical laboratory personnel, an appropriate model was developed and apply to the clinical laboratory personnel. Medical technologist who currently worked in clinical laboratory participated in this study. The proposed model consisted of 3 phases. 1) The knowledge providing via update and refresher courses. 2) Application of learned knowledge to practice under close supervision. 3) Training on special topic and self oriented research activity. The outcome of 5 years project was evaluated. After the first phase, they were able to identify and solve their own troublesome under ours close supervision. There were 25 projects presented within 3 years. The last phase, they were very constructive. Nine projects of self created had been presented. Those projects contained clear objectives and were able to implement. The smart model for clinical laboratory personnel development leaded to many self created projects in a few years. Thus, this implies its important role in human resource development that should be continued. The keys index of success were ours strong intention, with providing motivation and periodically encouragement to the participants, and keep going on consistently.

  20. Investigation and demonstration of a rich combustor cold-start device for alcohol-fueled engines

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, J W; Irick, D K [Univ. of Tennessee, Knoxville, TN (United States)

    1998-04-01

    The authors have completed a study in which they investigated the use of a rich combustor to aid in cold starting spark-ignition engines fueled with either neat ethanol or neat methanol. The rich combustor burns the alcohol fuel outside the engine under fuel-rich conditions to produce a combustible product stream that is fed to the engine for cold starting. The rich combustor approach significantly extends the cold starting capability of alcohol-fueled engines. A design tool was developed that simulates the operation of the combustor and couples it to an engine/vehicle model. This tool allows the user to determine the fuel requirements of the rich combustor as the vehicle executes a given driving mission. The design tool was used to design and fabricate a rich combustor for use on a 2.8 L automotive engine. The system was tested using a unique cold room that allows the engine to be coupled to an electric dynamometer. The engine was fitted with an aftermarket engine control system that permitted the fuel flow to the rich combustor to be programmed as a function of engine speed and intake manifold pressure. Testing indicated that reliable cold starts were achieved on both neat methanol and neat ethanol at temperatures as low as {minus}20 C. Although starts were experienced at temperatures as low as {minus}30 C, these were erratic. They believe that an important factor at the very low temperatures is the balance between the high mechanical friction of the engine and the low energy density of the combustible mixture fed to the engine from the rich combustor.

  1. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    NARCIS (Netherlands)

    Thy, P.; Jenkins, B.M.; Williams, R.B.; Lesher, C.E.; Bakker, R.R.

    2010-01-01

    Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run durations

  2. Model of supercapacitor with laboratory verification

    Directory of Open Access Journals (Sweden)

    Simić Mitar S.

    2014-01-01

    Full Text Available In this paper historical development and most important production technologies of supercapacitors are presented. Simple model of supecapacitor based on parameters obtained from manufacturer's datasheet is also realized. Purposed model is verified with charge, discharge and self-discharge tests with obtained results close to experimental.

  3. ISS Destiny Laboratory Smoke Detection Model

    Science.gov (United States)

    Brooker, John E.; Urban, David L.; Ruff, Gary A.

    2007-01-01

    Smoke transport and detection were modeled numerically in the ISS Destiny module using the NIST, Fire Dynamics Simulator code. The airflows in Destiny were modeled using the existing flow conditions and the module geometry included obstructions that simulate the currently installed hardware on orbit. The smoke source was modeled as a 0.152 by 0.152 m region that emitted smoke particulate ranging from 1.46 to 8.47 mg/s. In the module domain, the smoke source was placed in the center of each Destiny rack location and the model was run to determine the time required for the two smoke detectors to alarm. Overall the detection times were dominated by the circumferential flow, the axial flow from the intermodule ventilation and the smoke source strength.

  4. Modeling human influenza infection in the laboratory

    Directory of Open Access Journals (Sweden)

    Radigan KA

    2015-08-01

    Full Text Available Kathryn A Radigan,1 Alexander V Misharin,2 Monica Chi,1 GR Scott Budinger11Division of Pulmonary and Critical Care Medicine, 2Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USAAbstract: Influenza is the leading cause of death from an infectious cause. Because of its clinical importance, many investigators use animal models to understand the biologic mechanisms of influenza A virus replication, the immune response to the virus, and the efficacy of novel therapies. This review will focus on the biosafety, biosecurity, and ethical concerns that must be considered in pursuing influenza research, in addition to focusing on the two animal models – mice and ferrets – most frequently used by researchers as models of human influenza infection.Keywords: mice, ferret, influenza, animal model, biosafety

  5. Combustor assembly in a gas turbine engine

    Science.gov (United States)

    Wiebe, David J; Fox, Timothy A

    2013-02-19

    A combustor assembly in a gas turbine engine. The combustor assembly includes a combustor device coupled to a main engine casing, a first fuel injection system, a transition duct, and an intermediate duct. The combustor device includes a flow sleeve for receiving pressurized air and a liner disposed radially inwardly from the flow sleeve. The first fuel injection system provides fuel that is ignited with the pressurized air creating first working gases. The intermediate duct is disposed between the liner and the transition duct and defines a path for the first working gases to flow from the liner to the transition duct. An intermediate duct inlet portion is associated with a liner outlet and allows movement between the intermediate duct and the liner. An intermediate duct outlet portion is associated with a transition duct inlet section and allows movement between the intermediate duct and the transition duct.

  6. CFD analysis of a scramjet combustor with cavity based flame holders

    Science.gov (United States)

    Kummitha, Obula Reddy; Pandey, Krishna Murari; Gupta, Rajat

    2018-03-01

    Numerical analysis of a scramjet combustor with different cavity flame holders has been carried out using ANSYS 16 - FLUENT tool. In this research article the internal fluid flow behaviour of the scramjet combustor with different cavity based flame holders have been discussed in detail. Two dimensional Reynolds-Averaged Navier-Stokes governing(RANS) equations and shear stress turbulence (SST) k - ω model along with finite rate/eddy dissipation chemistry turbulence have been considered for modelling chemical reacting flows. Due to the advantage of less computational time, global one step reaction mechanism has been used for combustion modelling of hydrogen and air. The performance of the scramjet combustor with two different cavities namely spherical and step cavity has been compared with the standard DLR scramjet. From the comparison of numerical results, it is found that the development of recirculation regions and additional shock waves from the edge of cavity flame holder is increased. And also it is observed that with the cavity flame holder the residence time of air in the scramjet combustor is also increased and achieved stabilized combustion. From this research analysis, it has been found that the mixing and combustion efficiency of scramjet combustor with step cavity design is optimum as compared to other models.

  7. Terminology Modeling for an Enterprise Laboratory Orders Catalog

    Science.gov (United States)

    Zhou, Li; Goldberg, Howard; Pabbathi, Deepika; Wright, Adam; Goldman, Debora S.; Van Putten, Cheryl; Barley, Amanda; Rocha, Roberto A.

    2009-01-01

    Laboratory test orders are used in a variety of clinical information systems at Partners HealthCare. At present, each site at Partners manages its own set of laboratory orders with locally defined codes. Our current plan is to implement an enterprise catalog, where laboratory test orders are mapped to reference terminologies and codes from different sites are mapped to each other. This paper describes the terminology modeling effort that preceded the implementation of the enterprise laboratory orders catalog. In particular, we present our experience in adapting HL7’s “Common Terminology Services 2 – Upper Level Class Model” as a terminology metamodel for guiding the development of fully specified laboratory orders and related services. PMID:20351950

  8. Web Based Laboratory Task-Submitter Application Model

    Directory of Open Access Journals (Sweden)

    Soetam Rizky Wicaksono

    2010-04-01

    Full Text Available Teaching learning process in laboratory is obligatory in engineering education especially for course in information technology (IT. To make laboratory activities become more interesting for the students, lecturers must build application-based exercise for the student, but after students accomplished their short exercise, it is found that lecturers got difficulty to compile and grade all the exercises. This paper is based on the idea how to overcome the problem above, in order to make activities in the laboratory comfortable for both lectures and student. It is expected that the lectures will able to fully control all practical activity and save the time automatically. To make approach to solve the problem in IT, a modeling process must be conducted first. There for, firstly, this paper explain the model approach for the problem above, then the IT design for practices in laboratory is described. The IT design to overcome the problem has been effectively applied in the real teaching learning process.

  9. Clinical laboratory as an economic model for business performance analysis

    Science.gov (United States)

    Buljanović, Vikica; Patajac, Hrvoje; Petrovečki, Mladen

    2011-01-01

    Aim To perform SWOT (strengths, weaknesses, opportunities, and threats) analysis of a clinical laboratory as an economic model that may be used to improve business performance of laboratories by removing weaknesses, minimizing threats, and using external opportunities and internal strengths. Methods Impact of possible threats to and weaknesses of the Clinical Laboratory at Našice General County Hospital business performance and use of strengths and opportunities to improve operating profit were simulated using models created on the basis of SWOT analysis results. The operating profit as a measure of profitability of the clinical laboratory was defined as total revenue minus total expenses and presented using a profit and loss account. Changes in the input parameters in the profit and loss account for 2008 were determined using opportunities and potential threats, and economic sensitivity analysis was made by using changes in the key parameters. The profit and loss account and economic sensitivity analysis were tools for quantifying the impact of changes in the revenues and expenses on the business operations of clinical laboratory. Results Results of simulation models showed that operational profit of €470 723 in 2008 could be reduced to only €21 542 if all possible threats became a reality and current weaknesses remained the same. Also, operational gain could be increased to €535 804 if laboratory strengths and opportunities were utilized. If both the opportunities and threats became a reality, the operational profit would decrease by €384 465. Conclusion The operational profit of the clinical laboratory could be significantly reduced if all threats became a reality and the current weaknesses remained the same. The operational profit could be increased by utilizing strengths and opportunities as much as possible. This type of modeling may be used to monitor business operations of any clinical laboratory and improve its financial situation by

  10. Clinical laboratory as an economic model for business performance analysis.

    Science.gov (United States)

    Buljanović, Vikica; Patajac, Hrvoje; Petrovecki, Mladen

    2011-08-15

    To perform SWOT (strengths, weaknesses, opportunities, and threats) analysis of a clinical laboratory as an economic model that may be used to improve business performance of laboratories by removing weaknesses, minimizing threats, and using external opportunities and internal strengths. Impact of possible threats to and weaknesses of the Clinical Laboratory at Našice General County Hospital business performance and use of strengths and opportunities to improve operating profit were simulated using models created on the basis of SWOT analysis results. The operating profit as a measure of profitability of the clinical laboratory was defined as total revenue minus total expenses and presented using a profit and loss account. Changes in the input parameters in the profit and loss account for 2008 were determined using opportunities and potential threats, and economic sensitivity analysis was made by using changes in the key parameters. The profit and loss account and economic sensitivity analysis were tools for quantifying the impact of changes in the revenues and expenses on the business operations of clinical laboratory. Results of simulation models showed that operational profit of €470 723 in 2008 could be reduced to only €21 542 if all possible threats became a reality and current weaknesses remained the same. Also, operational gain could be increased to €535 804 if laboratory strengths and opportunities were utilized. If both the opportunities and threats became a reality, the operational profit would decrease by €384 465. The operational profit of the clinical laboratory could be significantly reduced if all threats became a reality and the current weaknesses remained the same. The operational profit could be increased by utilizing strengths and opportunities as much as possible. This type of modeling may be used to monitor business operations of any clinical laboratory and improve its financial situation by implementing changes in the next fiscal

  11. Dynamic Data-Driven Prediction of Lean Blowout in a Swirl-Stabilized Combustor

    Directory of Open Access Journals (Sweden)

    Soumalya Sarkar

    2015-09-01

    Full Text Available This paper addresses dynamic data-driven prediction of lean blowout (LBO phenomena in confined combustion processes, which are prevalent in many physical applications (e.g., land-based and aircraft gas-turbine engines. The underlying concept is built upon pattern classification and is validated for LBO prediction with time series of chemiluminescence sensor data from a laboratory-scale swirl-stabilized dump combustor. The proposed method of LBO prediction makes use of the theory of symbolic dynamics, where (finite-length time series data are partitioned to produce symbol strings that, in turn, generate a special class of probabilistic finite state automata (PFSA. These PFSA, called D-Markov machines, have a deterministic algebraic structure and their states are represented by symbol blocks of length D or less, where D is a positive integer. The D-Markov machines are constructed in two steps: (i state splitting, i.e., the states are split based on their information contents, and (ii state merging, i.e., two or more states (of possibly different lengths are merged together to form a new state without any significant loss of the embedded information. The modeling complexity (e.g., number of states of a D-Markov machine model is observed to be drastically reduced as the combustor approaches LBO. An anomaly measure, based on Kullback-Leibler divergence, is constructed to predict the proximity of LBO. The problem of LBO prediction is posed in a pattern classification setting and the underlying algorithms have been tested on experimental data at different extents of fuel-air premixing and fuel/air ratio. It is shown that, over a wide range of fuel-air premixing, D-Markov machines with D > 1 perform better as predictors of LBO than those with D = 1.

  12. Performance of low-Btu fuel gas turbine combustors

    Energy Technology Data Exchange (ETDEWEB)

    Bevan, S.; Bowen, J.H.; Feitelberg, A.S.; Hung, S.L.; Lacey, M.A.; Manning, K.S.

    1995-11-01

    This reports on a project to develop low BTU gas fuel nozzle for use in large gas turbine combustors using multiple fuel nozzles. A rich-quench-lean combustor is described here which reduces the amount of NO{sub x} produced by the combustion of the low BTU gas. The combustor incorporates a converging rich stage combustor liner, which separates the rich stage recirculation zones from the quench stage and lean stage air.

  13. Dental Biofilm and Laboratory Microbial Culture Models for Cariology Research

    Directory of Open Access Journals (Sweden)

    Ollie Yiru Yu

    2017-06-01

    Full Text Available Dental caries form through a complex interaction over time among dental plaque, fermentable carbohydrate, and host factors (including teeth and saliva. As a key factor, dental plaque or biofilm substantially influence the characteristic of the carious lesions. Laboratory microbial culture models are often used because they provide a controllable and constant environment for cariology research. Moreover, they do not have ethical problems associated with clinical studies. The design of the microbial culture model varies from simple to sophisticated according to the purpose of the investigation. Each model is a compromise between the reality of the oral cavity and the simplification of the model. Researchers, however, can still obtain meaningful and useful results from the models they select. Laboratory microbial culture models can be categorized into a closed system and an open system. Models in the closed system have a finite supply of nutrients, and are also simple and cost-effective. Models in the open system enabled the supply of a fresh culture medium and the removal of metabolites and spent culture liquid simultaneously. They provide better regulation of the biofilm growth rate than the models in the closed system. This review paper gives an overview of the dental plaque biofilm and laboratory microbial culture models used for cariology research.

  14. Computational simulation of multi-strut central lobed injection of hydrogen in a scramjet combustor

    Directory of Open Access Journals (Sweden)

    Gautam Choubey

    2016-09-01

    Full Text Available Multi-strut injection is an approach to increase the overall performance of Scramjet while reducing the risk of thermal choking in a supersonic combustor. Hence computational simulation of Scramjet combustor at Mach 2.5 through multiple central lobed struts (three struts have been presented and discussed in the present research article. The geometry and model used here is slight modification of the DLR (German Aerospace Center scramjet model. Present results show that the presence of three struts injector improves the performance of scramjet combustor as compared to single strut injector. The combustion efficiency is also found to be highest in case of three strut fuel injection system. In order to validate the results, the numerical data for single strut injection is compared with experimental result which is taken from the literature.

  15. Simulations of NOx Emissions from Low Emissions Discrete Jet Injector Combustor Tests

    Science.gov (United States)

    Ajmani, Kumud; Breisacher, Kevin

    2014-01-01

    An experimental and computational study was conducted to evaluate the performance and emissions characteristics of a candidate Lean Direct Injection (LDI) combustor configuration with a mix of simplex and airblast injectors. The National Combustion Code (NCC) was used to predict the experimentally measured EINOx emissions for test conditions representing low power, medium power, and high-power engine cycle conditions. Of the six cases modeled with the NCC using a reduced-kinetics finite-rate mechanism and lagrangian spray modeling, reasonable predictions of combustor exit temperature and EINOx were obtained at two high-power cycle conditions.

  16. Combustion oscillation study in a kerosene fueled rocket-based combined-cycle engine combustor

    Science.gov (United States)

    Huang, Zhi-Wei; He, Guo-Qiang; Qin, Fei; Xue, Rui; Wei, Xiang-Geng; Shi, Lei

    2016-12-01

    This study reports the combustion oscillation features in a three-dimensional (3D) rocket-based combined-cycle (RBCC) engine combustor under flight Mach number (Mflight) 3.0 conditions both experimentally and numerically. Experiment is performed on a direct-connect ground test facility, which measures the wall pressure along the flow-path. High-speed imaging of the flame luminosity and schlieren is carried out at exit of the primary rocket. Compressible reactive large eddy simulation (LES) with reduced chemical kinetics of a surrogate model for kerosene is performed to further understand the combustion oscillation mechanisms in the combustor. LES results are validated with experimental data by the time-averaged and root mean square (RMS) pressure values, and show acceptable agreement. Effects of the primary rocket jet on pressure oscillation in the combustor are analyzed. Relation of the high speed rocket jet oscillation, which is thought to among the most probable sources of combustion oscillation, with the RBCC combustor is recognized. Results reveal that the unsteady over-expanded rocket jet has significant impacts on the combustion oscillation feature of the RBCC combustor, which is different from a thermo-acoustics type oscillation. The rocket jet/air inflow physical interactions under different rocket jet expansion degrees are experimentally studied.

  17. Effects of Cavity Configurations on Flameholding and Performances of Kerosene Fueled Scramjet Combustor

    Science.gov (United States)

    Shi, Deyong; Song, Wenyan; Wang, Yuhang; Wang, Yanhua

    2017-08-01

    In this work, the effects of cavity flameholder configurations on flameholding and performances of kerosene fueled scramjet combustor were studied experimentally and numerically. For experiments, a directly connected ground facility was used and clean high enthalpy air, with a total temperature of 800 K and a total pressure of 800 Kpa, was provided by an electricity resistance heater. To investigate the effects of cavity configurations on flameholding capacity and reacting-flow characteristics, three different flameholders, one single cavity flameholder and two tandem cavity flameholders, were used in experiments. For the two combustors with tandem cavity flameholders, the location and configurations of its up-stream cavity were same with the single cavity flameholder, and the length-to-depth ratios for down-stream cavities were 9 and 11 respectively. The experimental results showed that stabilize kerosene combustion were achieved for combustor with tandem cavity flameholders mounted, and none for that with single cavity flameholder. The none-reacting and reacting flows of combustor models with tandem cavity flameholders were compared and studied with numerical and experimental results. The results showed that higher combustion efficiencies and pressure recovery ratios were achieved for the combustor with down-stream cavity length-to-depth ratio of 9.

  18. Fuel property effects on USAF gas turbine engine combustors and afterburners

    Science.gov (United States)

    Reeves, C. M.

    1984-01-01

    Since the early 1970s, the cost and availability of aircraft fuel have changed drastically. These problems prompted a program to evaluate the effects of broadened specification fuels on current and future aircraft engine combustors employed by the USAF. Phase 1 of this program was to test a set of fuels having a broad range of chemical and physical properties in a select group of gas turbine engine combustors currently in use by the USAF. The fuels ranged from JP4 to Diesel Fuel number two (DF2) with hydrogen content ranging from 14.5 percent down to 12 percent by weight, density ranging from 752 kg/sq m to 837 kg/sq m, and viscosity ranging from 0.830 sq mm/s to 3.245 sq mm/s. In addition, there was a broad range of aromatic content and physical properties attained by using Gulf Mineral Seal Oil, Xylene Bottoms, and 2040 Solvent as blending agents in JP4, JP5, JP8, and DF2. The objective of Phase 2 was to develop simple correlations and models of fuel effects on combustor performance and durability. The major variables of concern were fuel chemical and physical properties, combustor design factors, and combustor operating conditions.

  19. Diesel engine catalytic combustor system. [aircraft engines

    Science.gov (United States)

    Ream, L. W. (Inventor)

    1984-01-01

    A low compression turbocharged diesel engine is provided in which the turbocharger can be operated independently of the engine to power auxiliary equipment. Fuel and air are burned in a catalytic combustor to drive the turbine wheel of turbine section which is initially caused to rotate by starter motor. By opening a flapper value, compressed air from the blower section is directed to catalytic combustor when it is heated and expanded, serving to drive the turbine wheel and also to heat the catalytic element. To start, engine valve is closed, combustion is terminated in catalytic combustor, and the valve is then opened to utilize air from the blower for the air driven motor. When the engine starts, the constituents in its exhaust gas react in the catalytic element and the heat generated provides additional energy for the turbine section.

  20. An experimental study of the stable and unstable operation of an LPP gas turbine combustor

    Science.gov (United States)

    Dhanuka, Sulabh Kumar

    A study was performed to better understand the stable operation of an LPP combustor and formulate a mechanism behind the unstable operation. A unique combustor facility was developed at the University of Michigan that incorporates the latest injector developed by GE Aircraft Engines and enables operation at elevated pressures with preheated air at flow-rates reflective of actual conditions. The large optical access has enabled the use of a multitude of state-of-the-art laser diagnostics such as PIV and PLIF, and has shed invaluable light not only into the GE injector specifically but also into gas turbine combustors in general. Results from Particle Imaging Velocimetry (PIV) have illustrated the role of velocity, instantaneous vortices, and key recirculation zones that are all critical to the combustor's operation. It was found that considerable differences exist between the iso-thermal and reacting flows, and between the instantaneous and mean flow fields. To image the flame, Planar Laser Induced Fluorescence (PLIF) of the formaldehyde radical was successfully utilized for the first time in a Jet-A flame. Parameters regarding the flame's location and structure have been obtained that assist in interpreting the velocity results. These results have also shown that some of the fuel injected from the main fuel injectors actually reacts in the diffusion flame of the pilot. The unstable operation of the combustor was studied in depth to obtain the stability limits of the combustor, behavior of the flame dynamics, and frequencies of the oscillations. Results from simultaneous pressure and high speed chemiluminescence images have shown that the low frequency dynamics can be characterized as flashback oscillations. The results have also shown that the stability of the combustor can be explained by simple and well established premixed flame stability mechanisms. This study has allowed the development of a model that describes the instability mechanism and accurately

  1. Investigations on the Influence of the In-Stream Pylon and Strut on the Performance of a Scramjet Combustor

    Directory of Open Access Journals (Sweden)

    Hao Ouyang

    2014-01-01

    Full Text Available The influence of the in-stream pylon and strut on the performance of scramjet combustor was experimentally and numerically investigated. The experiments were conducted with a direct-connect supersonic model combustor equipped with multiple cavities. The entrance parameter of combustor corresponds to scramjet flight Mach number 4.0 with a total temperature of 947 K. The research results show that, compared with the scramjet combustor without pylon and strut, the wall pressure and the thrust of the scramjet increase due to the improvement of mixing and combustion effect due to the pylon and strut. The total pressure loss caused by the strut is considerable whereas pylon influence is slight.

  2. Experimental study on combustion modes and thrust performance of a staged-combustor of the scramjet with dual-strut

    Science.gov (United States)

    Yang, Qingchun; Chetehouna, Khaled; Gascoin, Nicolas; Bao, Wen

    2016-05-01

    To enable the scramjet operate in a wider flight Mach number, a staged-combustor with dual-strut is introduced to hold more heat release at low flight Mach conditions. The behavior of mode transition was examined using a direct-connect model scramjet experiment along with pressure measurements. The typical operating modes of the staged-combustor are analyzed. Fuel injection scheme has a significant effect on the combustor operating modes, particularly for the supersonic combustion mode. Thrust performances of the combustor with different combustion modes and fuel distributions are reported in this paper. The first-staged strut injection has a better engine performance in the operation of subsonic combustion mode. On the contrast, the second-staged strut injection has a better engine performance in the operation of supersonic combustion mode.

  3. Variable volume combustor with aerodynamic support struts

    Science.gov (United States)

    Ostebee, Heath Michael; Johnson, Thomas Edward; Stewart, Jason Thurman; Keener, Christopher Paul

    2017-03-07

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and providing the flow of fuel therethrough. The support struts may include an aerodynamic contoured shape so as to distribute evenly a flow of air to the micro-mixer fuel nozzles.

  4. E-laboratories : agent-based modeling of electricity markets.

    Energy Technology Data Exchange (ETDEWEB)

    North, M.; Conzelmann, G.; Koritarov, V.; Macal, C.; Thimmapuram, P.; Veselka, T.

    2002-05-03

    Electricity markets are complex adaptive systems that operate under a wide range of rules that span a variety of time scales. These rules are imposed both from above by society and below by physics. Many electricity markets are undergoing or are about to undergo a transition from centrally regulated systems to decentralized markets. Furthermore, several electricity markets have recently undergone this transition with extremely unsatisfactory results, most notably in California. These high stakes transitions require the introduction of largely untested regulatory structures. Suitable laboratories that can be used to test regulatory structures before they are applied to real systems are needed. Agent-based models can provide such electronic laboratories or ''e-laboratories.'' To better understand the requirements of an electricity market e-laboratory, a live electricity market simulation was created. This experience helped to shape the development of the Electricity Market Complex Adaptive Systems (EMCAS) model. To explore EMCAS' potential as an e-laboratory, several variations of the live simulation were created. These variations probed the possible effects of changing power plant outages and price setting rules on electricity market prices.

  5. Single particle behaviour in circulating fluidized bed combustors

    DEFF Research Database (Denmark)

    Erik Weinell, Claus

    1994-01-01

    of fuel particles in a boiler. A cold pilot scale model of a circulating fluidized bed combustor was used. Here sand was recirculated by means of air. Pressure measurements along the riser determined suspension density. A radioactive tracking facility to determined the dynamic picture of the particle...... trajectories in the simulated boiler. In the splash zone, closest to the secondary air inlet an exponential decay in the solids suspension density with the riser height was observed. A transport zone was characterized by an exponential decay in the solids suspension but with a smaller decay constant...

  6. Steam Reformer With Fibrous Catalytic Combustor

    Science.gov (United States)

    Voecks, Gerald E.

    1987-01-01

    Proposed steam-reforming reactor derives heat from internal combustion on fibrous catalyst. Supplies of fuel and air to combustor controlled to meet demand for heat for steam-reforming reaction. Enables use of less expensive reactor-tube material by limiting temperature to value safe for material yet not so low as to reduce reactor efficiency.

  7. Modeling of secondary organic aerosol yields from laboratory chamber data

    Directory of Open Access Journals (Sweden)

    M. N. Chan

    2009-08-01

    Full Text Available Laboratory chamber data serve as the basis for constraining models of secondary organic aerosol (SOA formation. Current models fall into three categories: empirical two-product (Odum, product-specific, and volatility basis set. The product-specific and volatility basis set models are applied here to represent laboratory data on the ozonolysis of α-pinene under dry, dark, and low-NOx conditions in the presence of ammonium sulfate seed aerosol. Using five major identified products, the model is fit to the chamber data. From the optimal fitting, SOA oxygen-to-carbon (O/C and hydrogen-to-carbon (H/C ratios are modeled. The discrepancy between measured H/C ratios and those based on the oxidation products used in the model fitting suggests the potential importance of particle-phase reactions. Data fitting is also carried out using the volatility basis set, wherein oxidation products are parsed into volatility bins. The product-specific model is most likely hindered by lack of explicit inclusion of particle-phase accretion compounds. While prospects for identification of the majority of SOA products for major volatile organic compounds (VOCs classes remain promising, for the near future empirical product or volatility basis set models remain the approaches of choice.

  8. Three Dimensional CFD Analysis of the GTX Combustor

    Science.gov (United States)

    Steffen, C. J., Jr.; Bond, R. B.; Edwards, J. R.

    2002-01-01

    The annular combustor geometry of a combined-cycle engine has been analyzed with three-dimensional computational fluid dynamics. Both subsonic combustion and supersonic combustion flowfields have been simulated. The subsonic combustion analysis was executed in conjunction with a direct-connect test rig. Two cold-flow and one hot-flow results are presented. The simulations compare favorably with the test data for the two cold flow calculations; the hot-flow data was not yet available. The hot-flow simulation Indicates that the conventional ejector-ramjet cycle would not provide adequate mixing at the conditions tested. The supersonic combustion ramjet flowfield was simulated with frozen chemistry model. A five-parameter test matrix was specified, according to statistical design-of-experiments theory. Twenty-seven separate simulations were used to assemble surrogate models for combustor mixing efficiency and total pressure recovery. Scramjet injector design parameters (injector angle, location, and fuel split) as well as mission variables (total fuel mass flow and freestream Mach number) were included in the analysis. A promising injector design has been identified that provides good mixing characteristics with low total pressure losses. The surrogate models can be used to develop performance maps of different injector designs. Several complex three-way variable interactions appear within the dataset that are not adequately resolved with the current statistical analysis.

  9. Bioethanol combustion in an industrial gas turbine combustor: simulations and experiments

    NARCIS (Netherlands)

    Sallevelt, J.L.H.P.; Pozarlik, Artur Krzysztof; Beran, Martin; Axelsson, L.; Brem, Gerrit

    2014-01-01

    Combustion tests with bioethanol and diesel as a reference have been performed in OPRA's 2 MWe class OP16 gas turbine combustor. The main purposes of this work are to investigate the combustion quality of ethanol with respect to diesel and to validate the developed CFD model for ethanol spray

  10. Overview of experimental measurements in a generic can-type gas turbine combustor

    CSIR Research Space (South Africa)

    Meyers, BC

    2009-11-01

    Full Text Available Due to CFD Shortfalls, experimental data on gas turbine combustors is required to obtain insight into the combustion and flow mechanisms as well as for simulation and model validation and evaluation. The temperature and velocity fields of a generic...

  11. Experimental and numerical simulation for swirl flow in a combustor

    Science.gov (United States)

    Dulin, V. M.; Markovich, D. M.; Minakov, A. V.; Hanjalic, K.; Chikishev, L. M.

    2013-12-01

    Results of the experimental and numerical simulation for swirl flow in combustion of a lean methane-air mixture in a model combustor at atmospheric pressure are represented. The panoramic method for the flow velocity measurement and the calculation by a large eddy method were used for the investigation of the nonstationary turbulent flow. The numerical modeling for the breakdown of the vortex core of the flow and the topology of large-scale vortex structures forming in it showed the close fit to the experiment. The analysis of obtained data showed that for the case of the intensive swirl of the flow as well as in the case of the flow without combustion, dynamics of the flow with combustion was determined by the global azimuthal instability mode corresponding to the intensive precession of the vortex core. The flame had the similar characteristics of the stability and compactness in the case of stabilization by the low swirl; however, velocity pulsations in the flow corresponded to the development of only local instability modes. Thus, the other kind of vortex breakdown in the case of the low swirl, for which the central recirculation zone is lacking, is not only favorable in view of the reduction of the NO x emission, but also remains a possibility for the effective use of the active control method for the flow and combustion. In particular, the given result may be used for the elimination of the thermoacoustic resonance in combustors.

  12. Behavioral effects of nerve agents: laboratory animal models

    International Nuclear Information System (INIS)

    Myers, T. M.

    2009-01-01

    Diverse and often subtle behavioral consequences have been reported for humans exposed to nerve agents. Laboratory studies of nerve agent exposure offer rigorous control over important variables, but species other than man must be used. Nonhuman primate models offer the best means of identifying the toxic nervous system effects of nerve agent insult and the countermeasures best capable of preventing or attenuating these effects. Comprehensive behavioral models must evaluate preservation and recovery of function as well as new learning ability. The throughput and sensitivity of the tests chosen are important considerations. A few nonhuman primate studies will be discussed to elaborate recent successes, current limitations, and future directions.(author)

  13. The combustion of refuse derived fuel on a ''Nordfab'' biomass combustor at Leonard Ironside Ltd

    Energy Technology Data Exchange (ETDEWEB)

    Fells, A.R.

    1991-08-01

    Warren Spring Laboratory has been assessing the performance of a Nordfab biofuel combustor fitted with a Danstoker boiler rated at 4.5MW (100% MCR), when firing Easiburn refuse derived fuel. The unit is situated at Leonard Ironside Ltd, a market gardening business near Lyminge Kent. A number of operational problems were encountered with the system, namely excessive fuel consumption and intermittent production of a persistent acrid plume. A trials history is given with details of monitoring methods used. The results of the test work show the reciprocating grate to be unsuitable for continuous firing of refuse derived fuel. The performance of the Nordfab combustor when burning refuse derived fuel is compared with two other units using similar fuel bed transport systems. These are the coking stoker and the Dantrim biofuel combustor. (author).

  14. Strengthening Laboratory Management Toward Accreditation, A Model Program for Pathology Laboratory Improvement.

    Science.gov (United States)

    Andiric, Linda R; Chavez, Lawrence A; Johnson, Mira; Landgraf, Kenneth; Milner, Danny A

    2018-03-01

    The Strengthening Laboratory Management Toward Accreditation (SLMTA) program and subsequent Stepwise Laboratory Quality Improvement Process Toward Accreditation (SLIPTA) checklist were a response to the need for high-quality laboratories to combat the human immunodeficiency virus (HIV) epidemic and provide patients with the highest-quality care. The two tools work together to create a culture of quality in laboratories and allow the identification of gaps. The ultimate goal for any laboratory is to achieve a standard benchmark for quality and these programs have been highly successful in initially affecting the HIV epidemic but continuously improving laboratory quality across all diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Flood Water Crossing: Laboratory Model Investigations for Water Velocity Reductions

    Directory of Open Access Journals (Sweden)

    Kasnon N.

    2014-01-01

    Full Text Available The occurrence of floods may give a negative impact towards road traffic in terms of difficulties in mobilizing traffic as well as causing damage to the vehicles, which later cause them to be stuck in the traffic and trigger traffic problems. The high velocity of water flows occur when there is no existence of objects capable of diffusing the water velocity on the road surface. The shape, orientation and size of the object to be placed beside the road as a diffuser are important for the effective flow attenuation of water. In order to investigate the water flow, a laboratory experiment was set up and models were constructed to study the flow velocity reduction. The velocity of water before and after passing through the diffuser objects was investigated. This paper focuses on laboratory experiments to determine the flow velocity of the water using sensors before and after passing through two best diffuser objects chosen from a previous flow pattern experiment.

  16. Large Engine Technology Program. Task 22: Variable Geometry Concepts for Rich-Quench-Lean Combustors

    Science.gov (United States)

    Tacina, Robert R. (Technical Monitor); Cohen, J. M.; Padget, F. C.; Kwoka, D.; Wang, Q.; Lohmann, R. P.

    2005-01-01

    The objective of the task reported herein was to define, evaluate, and optimize variable geometry concepts suitable for use with a Rich-Quench-Lean (RQL) combustor. The specific intent was to identify approaches that would satisfy High Speed Civil Transport (HSCT) cycle operational requirements with regard to fuel-air ratio turndown capability, ignition, and stability margin without compromising the stringent emissions, performance, and reliability goals that this combustor would have to achieve. Four potential configurations were identified and three of these were refined and tested in a high-pressure modular RQL combustor rig. The tools used in the evolution of these concepts included models built with rapid fabrication techniques that were tested for airflow characteristics to confirm sizing and airflow management capability, spray patternation, and atomization characterization tests of these models and studies that were supported by Computational Fluid Dynamics analyses. Combustion tests were performed with each of the concepts at supersonic cruise conditions and at other critical conditions in the flight envelope, including the transition points of the variable geometry system, to identify performance, emissions, and operability impacts. Based upon the cold flow characterization, emissions results, acoustic behavior observed during the tests and consideration of mechanical, reliability, and implementation issues, the tri-swirler configuration was selected as the best variable geometry concept for incorporation in the RQL combustor evolution efforts for the HSCT.

  17. Method for controlling incineration in combustor for radioactive wastes

    International Nuclear Information System (INIS)

    Takaoku, Y.; Uehara, A.

    1991-01-01

    This invention relates to a method for controlling incineration in a combustor for low-level radioactive wastes. In particular, it relates to a method for economizing in the consumption of supplemental fuel while maintaining a stable incineration state by controlling the amount of fuel and of radioactive wastes fed to the combustor. The amount of fuel supplied is determined by the outlet gas temperature of the combustor. (L.L.)

  18. Low NOx Fuel Flexible Combustor Integration Project Overview

    Science.gov (United States)

    Walton, Joanne C.; Chang, Clarence T.; Lee, Chi-Ming; Kramer, Stephen

    2015-01-01

    The Integrated Technology Demonstration (ITD) 40A Low NOx Fuel Flexible Combustor Integration development is being conducted as part of the NASA Environmentally Responsible Aviation (ERA) Project. Phase 2 of this effort began in 2012 and will end in 2015. This document describes the ERA goals, how the fuel flexible combustor integration development fulfills the ERA combustor goals, and outlines the work to be conducted during project execution.

  19. Design and implementation of a generalized laboratory data model

    Directory of Open Access Journals (Sweden)

    Nhan Mike

    2007-09-01

    Full Text Available Abstract Background Investigators in the biological sciences continue to exploit laboratory automation methods and have dramatically increased the rates at which they can generate data. In many environments, the methods themselves also evolve in a rapid and fluid manner. These observations point to the importance of robust information management systems in the modern laboratory. Designing and implementing such systems is non-trivial and it appears that in many cases a database project ultimately proves unserviceable. Results We describe a general modeling framework for laboratory data and its implementation as an information management system. The model utilizes several abstraction techniques, focusing especially on the concepts of inheritance and meta-data. Traditional approaches commingle event-oriented data with regular entity data in ad hoc ways. Instead, we define distinct regular entity and event schemas, but fully integrate these via a standardized interface. The design allows straightforward definition of a "processing pipeline" as a sequence of events, obviating the need for separate workflow management systems. A layer above the event-oriented schema integrates events into a workflow by defining "processing directives", which act as automated project managers of items in the system. Directives can be added or modified in an almost trivial fashion, i.e., without the need for schema modification or re-certification of applications. Association between regular entities and events is managed via simple "many-to-many" relationships. We describe the programming interface, as well as techniques for handling input/output, process control, and state transitions. Conclusion The implementation described here has served as the Washington University Genome Sequencing Center's primary information system for several years. It handles all transactions underlying a throughput rate of about 9 million sequencing reactions of various kinds per month and

  20. High pressure MHD coal combustors investigation, phase 2

    Science.gov (United States)

    Iwata, H.; Hamberg, R.

    1981-05-01

    A high pressure MHD coal combustor was investigated. The purpose was to acquire basic design and support engineering data through systematic combustion experiments at the 10 and 20 thermal megawatt size and to design a 50 MW/sub t/ combustor. This combustor is to produce an electrically conductive plasma generated by the direct combustion of pulverized coal with hot oxygen enriched vitiated air that is seeded with potassium carbonate. Vitiated air and oxygen are used as the oxidizer, however, preheated air will ultimately be used as the oxidizer in coal fired MHD combustors.

  1. Flame Propagation in a Dump Combustor with Shear Layer Excitation

    Data.gov (United States)

    National Aeronautics and Space Administration — This experimentation looks to investigate the use of fluidic oscillators to attenuate combustion instability in a naturally unstable rocket combustor. Since...

  2. Low pollution combustor designs for CTOL engines - Results of the Experimental Clean Combustor Program

    Science.gov (United States)

    Roberts, R.; Peduzzi, A.; Niedzwiecki, R. W.

    1976-01-01

    The NASA/Pratt & Whitney Aircraft Experimental Clean Combustor Program is a multi-year, major contract effort. Primary program objectives are the generation of combustor technology for development of advanced commercial CTOL engines with lower exhaust emissions than current aircraft and demonstration of this technology in a full-scale JT9D engine in 1976. This paper describes the pollution and performance goals, Phase I and II test results, and the Phase III combustor hardware, pollution sampling techniques, and test plans. Best results were obtained with the Vorbix concept which employs multiple burning zones and improved fuel preparation and distribution. Substantial reductions were achieved in all pollutant categories, meeting the 1979 EPA standards for NOx, THC, and smoke when extrapolated to JT9D cycle conditions. The Vorbix concept additionally demonstrated the capability for acceptable altitude relight and did not appear to have unsolvable durability or exit temperature distribution problems.

  3. Evaluation of a laboratory model of human head impact biomechanics.

    Science.gov (United States)

    Hernandez, Fidel; Shull, Peter B; Camarillo, David B

    2015-09-18

    This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests (~100 Hz) than field impacts (~10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Laboratory Plasma Source as an MHD Model for Astrophysical Jets

    Science.gov (United States)

    Mayo, Robert M.

    1997-01-01

    The significance of the work described herein lies in the demonstration of Magnetized Coaxial Plasma Gun (MCG) devices like CPS-1 to produce energetic laboratory magneto-flows with embedded magnetic fields that can be used as a simulation tool to study flow interaction dynamic of jet flows, to demonstrate the magnetic acceleration and collimation of flows with primarily toroidal fields, and study cross field transport in turbulent accreting flows. Since plasma produced in MCG devices have magnetic topology and MHD flow regime similarity to stellar and extragalactic jets, we expect that careful investigation of these flows in the laboratory will reveal fundamental physical mechanisms influencing astrophysical flows. Discussion in the next section (sec.2) focuses on recent results describing collimation, leading flow surface interaction layers, and turbulent accretion. The primary objectives for a new three year effort would involve the development and deployment of novel electrostatic, magnetic, and visible plasma diagnostic techniques to measure plasma and flow parameters of the CPS-1 device in the flow chamber downstream of the plasma source to study, (1) mass ejection, morphology, and collimation and stability of energetic outflows, (2) the effects of external magnetization on collimation and stability, (3) the interaction of such flows with background neutral gas, the generation of visible emission in such interaction, and effect of neutral clouds on jet flow dynamics, and (4) the cross magnetic field transport of turbulent accreting flows. The applicability of existing laboratory plasma facilities to the study of stellar and extragalactic plasma should be exploited to elucidate underlying physical mechanisms that cannot be ascertained though astrophysical observation, and provide baseline to a wide variety of proposed models, MHD and otherwise. The work proposed herin represents a continued effort on a novel approach in relating laboratory experiments to

  5. Compact Combustor Integrated (CI) with Compressor and Turbine for Perspective Turbojet Engine

    Science.gov (United States)

    Strokin, V. N.; Volkov, S. A.; Ljashenko, V. P.; Popov, V. I.; Startzev, A. N.; Nigmatullin, R. Z.; Shilova, T. V.; Belikov, U. V.

    2017-11-01

    For several years, CIAM has conducted comprehensive work on the development the combustor integrated (CI) with air swirling. This project involved an integrated development of three components: diffuser, combustion chamber and nozzle guide vanes of turbine to reduce their length and, respectively, the length of the engine and obtain high performance elements with low emissions of harmful substances. The new frontal device was proposed for CI combustor. The design optimization of this type combustor was conducted in the compartments and in a full-size combustion chamber. It was shown the possibility of obtaining high combustion efficiency and low NOx emissions at a short length on cruise condition. By a simplified model of the frontal device it was shown experimentally that the proposed device provided a lighting-up and flame spreading in a wide range of equivalence ratio ER (ER > 0.014) at idling. It was shown that short vane diffuser with moderate swirling ensured high parameters of the combustion chamber. The use of residual swirling of the combustion products at the exit of combustor allows reducing the size, or the number of nozzle guide vanes of the turbine. In General, the use of the swirling of the air stream gives a possibility of total length reduction for all three elements by about 20 – 25 %.

  6. Genetic algorithm to optimize the design of main combustor and gas generator in liquid rocket engines

    Science.gov (United States)

    Son, Min; Ko, Sangho; Koo, Jaye

    2014-06-01

    A genetic algorithm was used to develop optimal design methods for the regenerative cooled combustor and fuel-rich gas generator of a liquid rocket engine. For the combustor design, a chemical equilibrium analysis was applied, and the profile was calculated using Rao's method. One-dimensional heat transfer was assumed along the profile, and cooling channels were designed. For the gas-generator design, non-equilibrium properties were derived from a counterflow analysis, and a vaporization model for the fuel droplet was adopted to calculate residence time. Finally, a genetic algorithm was adopted to optimize the designs. The combustor and gas generator were optimally designed for 30-tonf, 75-tonf, and 150-tonf engines. The optimized combustors demonstrated superior design characteristics when compared with previous non-optimized results. Wall temperatures at the nozzle throat were optimized to satisfy the requirement of 800 K, and specific impulses were maximized. In addition, the target turbine power and a burned-gas temperature of 1000 K were obtained from the optimized gas-generator design.

  7. Operability of an Ejector Enhanced Pulse Combustor in a Gas Turbine Environment

    Science.gov (United States)

    Paxson, Daniel E.; Dougherty, Kevin

    2008-01-01

    A pressure-gain combustor comprised of a mechanically valved, liquid fueled pulsejet, an ejector, and an enclosing shroud, was coupled to a small automotive turbocharger to form a self-aspirating, thrust producing gas turbine engine. The system was constructed in order to investigate issues associated with the interaction of pulsed combustion devices and turbomachinery. Installed instrumentation allowed for sensing of distributed low frequency pressure and temperature, high frequency pressure in the shroud, fuel flow rate, rotational speed, thrust, and laboratory noise. The engine ran successfully and reliably, achieving a sustained thrust of 5 to 6 lbf, and maintaining a rotor speed of approximately 90,000 rpm, with a combustor pressure gain of approximately 4 percent. Numerical simulations of the system without pressure-gain combustion indicated that the turbocharger would not operate. Thus, the new combustor represented a substantial improvement in system performance. Acoustic measurements in the shroud and laboratory indicated turbine stage sound pressure level attenuation of 20 dB. This is consistent with published results from detonative combustion experiments. As expected, the mechanical reed valves suffered considerable damage under the higher pressure and thermal loading characteristics of this system. This result underscores the need for development of more robust valve systems for this application. The efficiency of the turbomachinery components did not appear to be significantly affected by unsteadiness associated with pulsed combustion, though the steady component efficiencies were already low, and thus not expected to be particularly sensitive.

  8. Large Eddy Simulations of a Premixed Jet Combustor Using Flamelet-Generated Manifolds: Effects of Heat Loss and Subgrid-Scale Models

    KAUST Repository

    Hernandez Perez, Francisco E.

    2017-01-05

    Large eddy simulations of a turbulent premixed jet flame in a confined chamber were conducted using the flamelet-generated manifold technique for chemistry tabulation. The configuration is characterized by an off-center nozzle having an inner diameter of 10 mm, supplying a lean methane-air mixture with an equivalence ratio of 0.71 and a mean velocity of 90 m/s, at 573 K and atmospheric pressure. Conductive heat loss is accounted for in the manifold via burner-stabilized flamelets and the subgrid-scale (SGS) turbulencechemistry interaction is modeled via presumed probability density functions. Comparisons between numerical results and measured data show that a considerable improvement in the prediction of temperature is achieved when heat losses are included in the manifold, as compared to the adiabatic one. Additional improvement in the temperature predictions is obtained by incorporating radiative heat losses. Moreover, further enhancements in the LES predictions are achieved by employing SGS models based on transport equations, such as the SGS turbulence kinetic energy equation with dynamic coefficients. While the numerical results display good agreement up to a distance of 4 nozzle diameters downstream of the nozzle exit, the results become less satisfactory along the downstream, suggesting that further improvements in the modeling are required, among which a more accurate model for the SGS variance of progress variable can be relevant.

  9. Radon transport in fractured soil. Laboratory experiments and modelling

    International Nuclear Information System (INIS)

    Hoff, A.

    1997-10-01

    Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs

  10. Leaching of saltstone: Laboratory and field testing and mathematical modeling

    International Nuclear Information System (INIS)

    Grant, M.W.; Langton, C.A.; Oblath, S.B.; Pepper, D.W.; Wallace, R.M.; Wilhite, E.L.; Yau, W.W.F.

    1987-01-01

    A low-level alkaline salt solution will be a byproduct in the processing of high-level waste at the Savannah River Plant (SRP). This solution will be incorporated into a wasteform, saltstone, and disposed of in surface vaults. Laboratory and field leach testing and mathematical modeling have demonstrated the predictability of contaminant release from cement wasteforms. Saltstone disposal in surface vaults will meet the design objective, which is to meet drinking water standards in shallow groundwater at the disposal area boundary. Diffusion is the predominant mechanism for release of contaminants to the environment. Leach testing in unsaturated soil, at soil moisture levels above 1 wt %, has shown no difference in leach rate compared to leaching in distilled water. Field leach testing of three thirty-ton blocks of saltstone in lysimeters has been underway since January 1984. Mathematical models were applied to assess design features for saltstone disposal. One dimensional infinite-composite and semi-infinite analytical models were developed for assessing diffusion of nitrate from saltstone through a cement barrier. Numerical models, both finite element and finite difference, were validated by comparison of model predictions with the saltstone lysimeter results. Validated models were used to assess the long-term performance of the saltstone stored in surface vaults. The maximum concentrations of all contaminants released from saltstone to shallow groundwater are predicted to be below drinking water standards at the disposal area boundary. 5 refs., 11 figs., 5 tabs

  11. [Experimental model of orthotopic uterus transplantation in the laboratory rat].

    Science.gov (United States)

    Ionac, M; Jiga, L; Motoc, A; Lupu, C; Bordoş, D

    2002-01-01

    This study develops and standardizes an experimental model of uterus transplantation in the laboratory rat. Twelve orthotropic uterus transplantation were done. Animals were randomized in three groups. Postoperative survival was 100% and 75% at 72 hours. Recipients were euthanased at 24 hours, 48 hours and 72 hours and the grafts were harvested. Patency of the microsurgical anastomoses was 100% at 24 hours, 63% at 48 hours and 0% at 72 hours. The explanted uterine grafts were fixed in formalize and analyzed under light microscopy. The acute allograft rejection starts during the second day after transplantation. In additional dissection, anatomy of the pelvic region with regard to the topography of the uterus, tube and ovarian vessels was studied. This model of uterus transplantation in rats proposes a standardized tool for further research regarding cellular mechanisms of the acute allograft rejection and, for future, pregnancy of the transplanted uterus.

  12. An Empirical Ultra Wideband Channel Model for Indoor Laboratory Environments

    Directory of Open Access Journals (Sweden)

    A. Abolghasemi

    2009-04-01

    Full Text Available Channel measurement and modeling is an important issue when designing ultra wideband (UWB communication systems. In this paper, the results of some UWB time-domain propagation measurements performed in modern laboratory (Lab environments are presented. The Labs are equipped with many electronic and measurement devices which make them different from other indoor locations like office and residential environments. The measurements have been performed for both line of sight (LOS and non-LOS (NLOS scenarios. The measurement results are used to investigate large-scale channel characteristics and temporal dispersion parameters. The clustering Saleh- Valenzuela (S-V channel impulse response (CIR parameters are investigated based on the measurement data. The small-scale amplitude fading statistics are also studied in the environment. Then, an empirical model is presented for UWB signal transmission in the Lab environment based on the obtained results.

  13. Verification of the karst flow model under laboratory controlled conditions

    Science.gov (United States)

    Gotovac, Hrvoje; Andric, Ivo; Malenica, Luka; Srzic, Veljko

    2016-04-01

    Karst aquifers are very important groundwater resources around the world as well as in coastal part of Croatia. They consist of extremely complex structure defining by slow and laminar porous medium and small fissures and usually fast turbulent conduits/karst channels. Except simple lumped hydrological models that ignore high karst heterogeneity, full hydraulic (distributive) models have been developed exclusively by conventional finite element and finite volume elements considering complete karst heterogeneity structure that improves our understanding of complex processes in karst. Groundwater flow modeling in complex karst aquifers are faced by many difficulties such as a lack of heterogeneity knowledge (especially conduits), resolution of different spatial/temporal scales, connectivity between matrix and conduits, setting of appropriate boundary conditions and many others. Particular problem of karst flow modeling is verification of distributive models under real aquifer conditions due to lack of above-mentioned information. Therefore, we will show here possibility to verify karst flow models under the laboratory controlled conditions. Special 3-D karst flow model (5.6*2.6*2 m) consists of concrete construction, rainfall platform, 74 piezometers, 2 reservoirs and other supply equipment. Model is filled by fine sand (3-D porous matrix) and drainage plastic pipes (1-D conduits). This model enables knowledge of full heterogeneity structure including position of different sand layers as well as conduits location and geometry. Moreover, we know geometry of conduits perforation that enable analysis of interaction between matrix and conduits. In addition, pressure and precipitation distribution and discharge flow rates from both phases can be measured very accurately. These possibilities are not present in real sites what this model makes much more useful for karst flow modeling. Many experiments were performed under different controlled conditions such as different

  14. Characterisation of Interaction between Combustion Dynamics and Equivalence Ratio Oscillations in a Pressurised Combustor

    Directory of Open Access Journals (Sweden)

    Jaap F. van Kampen

    2010-09-01

    Full Text Available In regular operation, all gas turbine combustors have a significant spontaneous noise level induced by the turbulent high power flame. This noise is characteristic for the operation as it is the result of the interaction between turbulence and combustion. Pressure fluctuations may also be generated by thermoacoustic instabilities induced by amplification by the flame of the acoustic field in the combustor. This paper focuses on the characterisation of the latter process, the combustion dynamics, in a pressurized premixed natural gas combustor. In order to predict the thermo-acoustically unstable operating ranges of modern gas-turbines with the use of an acoustic network model, it is essential to determine accurately the flame transfer function. This transfer function gives the relationship between a perturbation upstream of the flame and its combustion response, leading to acoustic forcing. In this paper, the flame transfer function is obtained by experimental means in a combustor test rig. This test rig was built in the framework of the European DESIRE project, and has the ability to perform thermo-acoustic measurements up to an absolute pressure of 5 bars. The maximum power of the setup is 500 kW. The paper presents a method to determine the flame transfer function by factorizing it in six subfunctions. Systematically these subfunctions are determined. With the method presented, acoustic measurements on the steady, unperturbed flame and on the unsteady, actively perturbed flame are performed. The effect of pressure is investigated. The steady measurements are used to provide an acousto-combustion finger print of the combustor. In the unsteady measurements, the flame transfer function is reconstructed from the measured acoustic pressures. These flame transfer functions are compared to transfer functions obtained from a numerical experiment in CFD. Good agreement is obtained.

  15. Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

    Energy Technology Data Exchange (ETDEWEB)

    Ahsan Choudhuri

    2011-03-31

    Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards

  16. Near-zero emissions combustor system for syngas and biofuels

    International Nuclear Information System (INIS)

    Yongho, Kim; Rosocha, Louis

    2010-01-01

    A multi-institutional plasma combustion team was awarded a research project from the DOE/NNSA GIPP (Global Initiative for Prolifereation Prevention) office. The Institute of High Current Electronics (Tomsk, Russia); Leonardo Technologies, Inc. (an American-based industrial partner), in conjunction with the Los Alamos National Laboratory are participating in the project to develop novel plasma assisted combustion technologies. The purpose of this project is to develop prototypes of marketable systems for more stable and cleaner combustion of syngas/biofuels and to demonstrate that this technology can be used for a variety of combustion applications - with a major focus on contemporary gas turbines. In this paper, an overview of the project, along with descriptions of the plasma-based combustors and associated power supplies will be presented. Worldwide, it is recognized that a variety of combustion fuels will be required to meet the needs for supplying gas-turbine engines (electricity generation, propulsion), internal combustion engines (propulsion, transportation), and burners (heat and electricity generation) in the 21st Century. Biofuels and biofuel blends have already been applied to these needs, but experience difficulties in modifications to combustion processes and combustor design and the need for flame stabilization techniques to address current and future environmental and energy-efficiency challenges. In addition, municipal solid waste (MSW) has shown promise as a feedstock for heat and/or electricity-generating plants. However, current combustion techniques that use such fuels have problems with achieving environmentally-acceptable air/exhaust emissions and can also benefit from increased combustion efficiency. This project involves a novel technology (a form of plasma-assisted combustion) that can address the above issues. Plasma-assisted combustion (PAC) is a growing field that is receiving worldwide attention at present. The project is focused on

  17. Combustor nozzle for a fuel-flexible combustion system

    Science.gov (United States)

    Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  18. Variable volume combustor with nested fuel manifold system

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-13

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles, a fuel manifold system in communication with the micro-mixer fuel nozzles to deliver a flow of fuel thereto, and a linear actuator to maneuver the micro-mixer fuel nozzles and the fuel manifold system.

  19. Variable volume combustor with pre-nozzle fuel injection system

    Science.gov (United States)

    Keener, Christopher Paul; Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Ostebee, Heath Michael

    2016-09-06

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of fuel nozzles, a pre-nozzle fuel injection system supporting the fuel nozzles, and a linear actuator to maneuver the fuel nozzles and the pre-nozzle fuel injection system.

  20. Variable volume combustor with a conical liner support

    Science.gov (United States)

    Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Keener, Chrisophter Paul; Ostebee, Heath Michael

    2017-06-27

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a conical liner support supporting the liner.

  1. The design of dapog rice seeder model for laboratory scale

    Science.gov (United States)

    Purba, UI; Rizaldi, T.; Sumono; Sigalingging, R.

    2018-02-01

    The dapog system is seeding rice seeds using a special nursery tray. Rice seedings with dapog systems can produce seedlings in the form of higher quality and uniform seed rolls. This study aims to reduce the cost of making large-scale apparatus by designing models for small-scale and can be used for learning in the laboratory. Parameters observed were soil uniformity, seeds and fertilizers, soil looses, seeds and fertilizers, effective capacity of apparatus, and power requirements. The results showed a high uniformity in soil, seed and fertilizer respectively 92.8%, 1-3 seeds / cm2 and 82%. The scattered materials for soil, seed and fertilizer were respectively 6.23%, 2.7% and 2.23%. The effective capacity of apparatus was 360 boxes / hour with 237.5 kWh of required power.

  2. LLIMAS: Revolutionizing integrating modeling and analysis at MIT Lincoln Laboratory

    Science.gov (United States)

    Doyle, Keith B.; Stoeckel, Gerhard P.; Rey, Justin J.; Bury, Mark E.

    2017-08-01

    MIT Lincoln Laboratory's Integrated Modeling and Analysis Software (LLIMAS) enables the development of novel engineering solutions for advanced prototype systems through unique insights into engineering performance and interdisciplinary behavior to meet challenging size, weight, power, environmental, and performance requirements. LLIMAS is a multidisciplinary design optimization tool that wraps numerical optimization algorithms around an integrated framework of structural, thermal, optical, stray light, and computational fluid dynamics analysis capabilities. LLIMAS software is highly extensible and has developed organically across a variety of technologies including laser communications, directed energy, photometric detectors, chemical sensing, laser radar, and imaging systems. The custom software architecture leverages the capabilities of existing industry standard commercial software and supports the incorporation of internally developed tools. Recent advances in LLIMAS's Structural-Thermal-Optical Performance (STOP), aeromechanical, and aero-optical capabilities as applied to Lincoln prototypes are presented.

  3. System and method for reducing combustion dynamics in a combustor

    Science.gov (United States)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Srinivasan, Shiva; York, William David

    2016-11-29

    A system for reducing combustion dynamics in a combustor includes an end cap that extends radially across the combustor and includes an upstream surface axially separated from a downstream surface. A combustion chamber is downstream of the end cap, and tubes extend from the upstream surface through the downstream surface. Each tube provides fluid communication through the end cap to the combustion chamber. The system further includes means for reducing combustion dynamics in the combustor. A method for reducing combustion dynamics in a combustor includes flowing a working fluid through tubes that extend axially through an end cap that extends radially across the combustor and obstructing at least a portion of the working fluid flowing through a first set of the tubes.

  4. Parametric Design of Injectors for LDI-3 Combustors

    Science.gov (United States)

    Ajmani, Kumud; Mongia, Hukam; Lee, Phil

    2015-01-01

    Application of a partially calibrated National Combustion Code (NCC) for providing guidance in the design of the 3rd generation of the Lean-Direct Injection (LDI) multi-element combustion configuration (LDI-3) is summarized. NCC was used to perform non-reacting and two-phase reacting flow computations on several LDI-3 injector configurations in a single-element and a five-element injector array. All computations were performed with a consistent approach for mesh-generation, turbulence, spray simulations, ignition and chemical kinetics-modeling. Both qualitative and quantitative assessment of the computed flowfield characteristics of the several design options led to selection of an optimal injector LDI- 3 design that met all the requirements including effective area, aerodynamics and fuel-air mixing criteria. Computed LDI-3 emissions (namely, NOx, CO and UHC) will be compared with the prior generation LDI- 2 combustor experimental data at relevant engine cycle conditions.

  5. Laser High-Cycle Thermal Fatigue of Pulse Detonation Engine Combustor Materials Tested

    Science.gov (United States)

    Zhu, Dong-Ming; Fox, Dennis S.; Miller, Robert A.

    2001-01-01

    Pulse detonation engines (PDE's) have received increasing attention for future aerospace propulsion applications. Because the PDE is designed for a high-frequency, intermittent detonation combustion process, extremely high gas temperatures and pressures can be realized under the nearly constant-volume combustion environment. The PDE's can potentially achieve higher thermodynamic cycle efficiency and thrust density in comparison to traditional constant-pressure combustion gas turbine engines (ref. 1). However, the development of these engines requires robust design of the engine components that must endure harsh detonation environments. In particular, the detonation combustor chamber, which is designed to sustain and confine the detonation combustion process, will experience high pressure and temperature pulses with very short durations (refs. 2 and 3). Therefore, it is of great importance to evaluate PDE combustor materials and components under simulated engine temperatures and stress conditions in the laboratory. In this study, a high-cycle thermal fatigue test rig was established at the NASA Glenn Research Center using a 1.5-kW CO2 laser. The high-power laser, operating in the pulsed mode, can be controlled at various pulse energy levels and waveform distributions. The enhanced laser pulses can be used to mimic the time-dependent temperature and pressure waves encountered in a pulsed detonation engine. Under the enhanced laser pulse condition, a maximum 7.5-kW peak power with a duration of approximately 0.1 to 0.2 msec (a spike) can be achieved, followed by a plateau region that has about one-fifth of the maximum power level with several milliseconds duration. The laser thermal fatigue rig has also been developed to adopt flat and rotating tubular specimen configurations for the simulated engine tests. More sophisticated laser optic systems can be used to simulate the spatial distributions of the temperature and shock waves in the engine. Pulse laser high

  6. The link between laboratory/field observations and models

    International Nuclear Information System (INIS)

    Cole, C.R.; Foley, M.G.

    1986-01-01

    The various linkages in system performance assessments that integrate disposal program elements must be understood. The linkage between model development and field/laboratory observations is described as the iterative program of site and system characterization for development of an observational-confirmatory data base. This data base is designed to develop, improve, and support conceptual models for site and system behavior. The program consists of data gathering and experiments to demonstrate understanding at various spatial and time scales and degrees of complexity. Understanding and accounting for the decreasing characterization certainty that arises with increasing space and time scales is an important aspect of the link between models and observations. The performance allocation process for setting performance goals and confidence levels, coupled with a performance assessment approach that provides these performance and confidence estimates, will determine when sufficient characterization has been achieved. At each iteration, performance allocation goals are reviewed and revised as necessary. The updated data base and appropriate performance assessment tools and approaches are utilized to identify and design additional tests and data needs necessary to meet current performance allocation goals

  7. Flame dynamics in a micro-channeled combustor

    International Nuclear Information System (INIS)

    Hussain, Taaha; Balachandran, Ramanarayanan; Markides, Christos N.

    2015-01-01

    The increasing use of Micro-Electro-Mechanical Systems (MEMS) has generated a significant interest in combustion-based power generation technologies, as a replacement of traditional electrochemical batteries which are plagued by low energy densities, short operational lives and low power-to-size and power-to-weight ratios. Moreover, the versatility of integrated combustion-based systems provides added scope for combined heat and power generation. This paper describes a study into the dynamics of premixed flames in a micro-channeled combustor. The details of the design and the geometry of the combustor are presented in the work by Kariuki and Balachandran [1]. This work showed that there were different modes of operation (periodic, a-periodic and stable), and that in the periodic mode the flame accelerated towards the injection manifold after entering the channels. The current study investigates these flames further. We will show that the flame enters the channel and propagates towards the injection manifold as a planar flame for a short distance, after which the flame shape and propagation is found to be chaotic in the middle section of the channel. Finally, the flame quenches when it reaches the injector slots. The glow plug position in the exhaust side ignites another flame, and the process repeats. It is found that an increase in air flow rate results in a considerable increase in the length (and associated time) over which the planar flame travels once it has entered a micro-channel, and a significant decrease in the time between its conversion into a chaotic flame and its extinction. It is well known from the literature that inside small channels the flame propagation is strongly influenced by the flow conditions and thermal management. An increase of the combustor block temperature at high flow rates has little effect on the flame lengths and times, whereas at low flow rates the time over which the planar flame front can be observed decreases and the time of

  8. Combustor nozzles in gas turbine engines

    Science.gov (United States)

    Johnson, Thomas Edward; Keener, Christopher Paul; Stewart, Jason Thurman; Ostebee, Heath Michael

    2017-09-12

    A micro-mixer nozzle for use in a combustor of a combustion turbine engine, the micro-mixer nozzle including: a fuel plenum defined by a shroud wall connecting a periphery of a forward tube sheet to a periphery of an aft tubesheet; a plurality of mixing tubes extending across the fuel plenum for mixing a supply of compressed air and fuel, each of the mixing tubes forming a passageway between an inlet formed through the forward tubesheet and an outlet formed through the aft tubesheet; and a wall mixing tube formed in the shroud wall.

  9. 2002 Defense Modeling and Simulation Office (DMSO) Laboratory for Human Behavior Model Interchange Standards

    Science.gov (United States)

    2003-07-01

    among Human Behavior Modeling (HEM) -related models in the Department of Defense (DoD), Industry, Academia, and other Government simulations by...establishing a Laboratory for the Study of Human Behavior Representation Interchange Standard. With experience, expertise, and technologies of the

  10. Experiments and computations on coaxial swirling jets with centerbody in an axisymmetric combustor

    International Nuclear Information System (INIS)

    Chao, Y.C.; Ho, W.C.; Lin, S.K.

    1987-01-01

    Experiments and computations of turbulent, confined, coannular swirling flows have been performed in a model combustor. Numerical results are obtained by means of a revised two-equation model of turbulence. The combustor consists of two confined, concentric, swirling jets and a centerbody at the center of the inlet. Results are reported for cold flow conditions under co- and counter-swirl. The numerical results agree with the experimental data under both conditions. The size of the central recirculation zone is dominated by the strength of the outer swirl. A two-cell recirculation zone may be formed due to the presence of the swirler hub. The mechanism of interaction between the separation bubble at the hub of the swirler and the central recirculation zone due to vortex breakdown is also investigated. 18 references

  11. Fluid Mechanics of Lean Blowout Precursors in Gas Turbine Combustors

    Directory of Open Access Journals (Sweden)

    T. M. Muruganandam

    2012-03-01

    Full Text Available Understanding of lean blowout (LBO phenomenon, along with the sensing and control strategies could enable the gas turbine combustor designers to design combustors with wider operability regimes. Sensing of precursor events (temporary extinction-reignition events based on chemiluminescence emissions from the combustor, assessing the proximity to LBO and using that data for control of LBO has already been achieved. This work describes the fluid mechanic details of the precursor dynamics and the blowout process based on detailed analysis of near blowout flame behavior, using simultaneous chemiluminescence and droplet scatter observations. The droplet scatter method represents the regions of cold reactants and thus help track unburnt mixtures. During a precursor event, it was observed that the flow pattern changes significantly with a large region of unburnt mixture in the combustor, which subsequently vanishes when a double/single helical vortex structure brings back the hot products back to the inlet of the combustor. This helical pattern is shown to be the characteristic of the next stable mode of flame in the longer combustor, stabilized by double helical vortex breakdown (VBD mode. It is proposed that random heat release fluctuations near blowout causes VBD based stabilization to shift VBD modes, causing the observed precursor dynamics in the combustor. A complete description of the evolution of flame near the blowout limit is presented. The description is consistent with all the earlier observations by the authors about precursor and blowout events.

  12. Numerical Investigation of Detonation Combustion Wave in Pulse Detonation Combustor with Ejector

    OpenAIRE

    P. Debnath; K. M. Pandey

    2017-01-01

    Detonation combustion based engines are more efficient compared to conventional deflagration based engines. Pulse detonation engine is the new concept in propulsion technology for future propulsion system. In this contrast, an ejector was used to modify the detonation wave propagation structure in pulse detonation engine combustor. In this paper k-ε turbulence model was used for detonation wave shock pattern simulation in PDE with ejectors at Ansys 14 Fluent platform. The unsteady Euler equat...

  13. Coupling between Hydrodynamics, Acoustics, and Heat Release in a Self-Excited Unstable Combustor

    Science.gov (United States)

    2015-04-07

    and K. N. Bray, “Self-excited oscillations in combustors with Spray atomizers,” J. Eng. Gas Turbines Power 4, 779-786 (2001). 23 Z. Yao, Y. Gao, M. Zhu...of the k-ω turbulence model revisited,” AIAA J. 46(11), 2823-2838 (2008). 56 C. Westbrook and F. Dryer , “Simplified reaction mechanisms for the

  14. Laboratory and Numerical Modeling of Smoke Characteristics for Superfog Formation

    Science.gov (United States)

    Bartolome, C.; Lu, V.; Tsui, K.; Princevac, M.; Venkatram, A.; Mahalingam, S.; Achtemeier, G.; Weise, D.

    2011-12-01

    Land management techniques in wildland areas include prescribed fires to promote biodiversity and reduce risk of severe wildfires across the United States. Several fatal car pileups have been associated with smoke-related visibility reduction from prescribed burns. Such events have occurred in year 2000 on the interstate highways I-10 and I-95, 2001 on the I-4, 2006 on the I-95, and 2008 on the I-4 causing numerous fatalities, injuries, and damage to property. In some of the cases visibility reduction caused by smoke and fog combinations traveling over roadways have been reported to be less than 3 meters, defined as superfog. Our research focuses on delineating the conditions that lead to formation of the rare phenomena of superfog and creating a tool to enable land managers to effectively plan prescribed burns and prevent tragic events. It is hypothesized that the water vapor from combustion, live fuels, soil moisture, and ambient air condense onto the cloud condensation nuclei (CCN) particles emitted from low intensity smoldering fires. Physical and numerical modeling has been used to investigate these interactions. A physical model in the laboratory has been developed to characterize the properties of smoke resulting from smoldering pine needle litters at the PSW Forest Service in Riverside, CA. Temporal measurements of temperature, relative humidity, sensible heat flux, radiation heat flux, convective heat flux, particulate matter concentrations and visibilities have been measured for specific cases. The size distribution and number concentrations of the fog droplets formed inside the chamber by mixing cool dry and moist warm air masses to produce near superfog visibilities were measured by a Phase Doppler Particle Analyzer. Thermodynamic modeling of smoke and ambient air was conducted to estimate liquid water contents (LWC) available to condense into droplets and form significant reductions in visibility. The results show that LWC of less than 2 g m-3 can be

  15. CFD Analysis of Fuel Atomization, Secondary Droplet Breakup and Spray Dispersion in the Premix Duct of a LPP Combustor

    NARCIS (Netherlands)

    Schmehl, R.; Maier, G.; Wittig, S.

    2000-01-01

    The two phase flow in the premix duct of a LPP combustor is computed using a Lagrangian droplet tracking method. To reproduce the characteristic spray structure of an air-assisted pressure-swirl atomizer, a sheet spray model is de-rived from measured sheet parameters and combined with an advanced

  16. Thermodynamic optimisation and computational analysis of irreversibilities in a small-scale wood-fired circulating fluidised bed adiabatic combustor

    CSIR Research Space (South Africa)

    Baloyi, J

    2014-06-01

    Full Text Available An analysis of irreversibilities generated due to combustion in an adiabatic combustor burning wood was conducted. This was done for a reactant mixture varying from a rich to a lean mixture. A non-adiabatic non-premixed combustion model of a...

  17. Large Eddy Simulations and Experimental Investigation of Flow in a Swirl Stabilized Combustor

    KAUST Repository

    Kewlani, Gaurav

    2012-01-09

    Swirling flows are the preferred mode of flame stabilization in lean premixed gas turbine engine combustors. Developing a fundamental understanding of combustion dynamics and flame stability in such systems requires a detailed investigation of the complex interactions between fluid mechanics and combustion. The turbulent reacting flow in a sudden expansion swirl combustor is studied using compressible large eddy simulations (LES) and compared with experimental data measured using PIV. Different vortex breakdown structures are observed, as the mixture equivalence ratio is reduced, that progressively diminish the stability of the flame. Sub-grid scale combustion models such as the artificially thickened flame method and the partially stirred reactor approach, along with appropriate chemical schemes, are implemented to describe the flame. The numerical predictions for average velocity correspond well with experimental results, and higher accuracy is obtained using the more detailed reaction mechanism. Copyright © 2012 American Institute of Aeronautics and Astronautics, Inc.

  18. Diffuse interfacelets in transcritical flows of propellants into high-pressure combustors

    Science.gov (United States)

    Urzay, Javier; Jofre, Lluis

    2017-11-01

    Rocket engines and new generations of high-power jet engines and diesel engines oftentimes involve the injection of one or more reactants at subcritical temperatures into combustor environments at high pressures, and more particularly, at pressures higher than those corresponding to the critical points of the individual components of the mixture, which typically range from 13 to 50 bars for most propellants. This class of trajectories in the thermodynamic space has been traditionally referred to as transcritical. Under particular conditions often found in hydrocarbon-fueled chemical propulsion systems, and despite the prevailing high pressures, the flow in the combustor may contain regions close to the injector where a diffuse interface is formed in between the fuel and oxidizer streams that is sustained by surface-tension forces as a result of the elevation of the critical pressure of the mixture. This talk describes progress towards modeling these effects in the conservation equations. Funded by the US Department of Energy.

  19. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    DEFF Research Database (Denmark)

    Thy, Peter; Jenkins, Brian; Williams, R.B.

    2010-01-01

    Abstract Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run...... areas between bed particles, ultimately led to bed agglomeration. The interfaces and the presence of gas bubbles in the cement suggest a bonding material with a high surface tension and a liquid state. The cement films originate by filling of irregularities on individual and partially agglomerated bed...

  20. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 1: User's manual

    Science.gov (United States)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The user's manual for the rocket combustor interactive design (ROCCID) computer program is presented. The program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial, and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can easily be added. The analysis model in ROCCID can account for the influence of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  1. Development of a Soybean Sowing Model Under Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Jan Turan

    2017-01-01

    Full Text Available Sowing is affected by numerous factors, and thus high‑quality sowing is a very important task for agricultural engineers and managers of profitable agricultural production. The primary purpose of sowing is placing seeds at proper depths and in‑row spacings in well‑prepared soil. Plant population particularly gives prominence to sowing as it directly affects the uniformity of plant growth and development. Soybean planting is especially dependent on the quality of planting for yield formation due to the significant vicinity of seeds. Provided all external factors of high‑quality sowing are met, i.e. sowing conditions, the quality of sowing depends upon the planting mechanism. The following features of the planting mechanism are the most important: RPM of the seed disc, the travel speed of a seeder, and the values of gauge and vacuum pressure. This paper presents the results of sowing three different fractions of soybean seeds under laboratory conditions. The quality measurement of sowing was performed at different values of vacuum pressure and RPM of the seed disc. On balance, an increase in vacuum pressure results in improved sowing quality due to a stronger adherence of seeds to the seed disc. Lower values of vacuum pressure do not exert significant effects on the quality of sowing, regardless of the seed fraction. However, higher RPM of the seed disc entail an increase in the coefficient of variation. On the basis of the results obtained, a mathematical model for predicting changes in the coefficient of variation of sowing quality was developed using different operating parameters.

  2. Combustion generated noise in gas turbine combustors

    Science.gov (United States)

    Strahle, W. C.; Shivashankara, B. N.

    1975-01-01

    Experiments are conducted for the noise power and spectra emitted from a gas turbine combustor can exhausting to the atmosphere. The theory of combustion noise is applied to the results to determine the noise generating capability of the flame in the absence of reflecting can surfaces. The results show that for a fixed fuel (JP-4) the noise output is independent of fuel/air ratio for well stabilized can-type flames and heavily dependent on airflow while the spectra are dominated by the can acoustics, primarily through sound absorption by the liner. In an installed configuration the noise output depends heavily on the enclosure acoustics. Scaling rules are presented for installed configurations.

  3. Method for operating a combustor in a fuel cell system

    Science.gov (United States)

    Chalfant, Robert W.; Clingerman, Bruce J.

    2002-01-01

    A method of operating a combustor to heat a fuel processor in a fuel cell system, in which the fuel processor generates a hydrogen-rich stream a portion of which is consumed in a fuel cell stack and a portion of which is discharged from the fuel cell stack and supplied to the combustor, and wherein first and second streams are supplied to the combustor, the first stream being a hydrocarbon fuel stream and the second stream consisting of said hydrogen-rich stream, the method comprising the steps of monitoring the temperature of the fuel processor; regulating the quantity of the first stream to the combustor according to the temperature of the fuel processor; and comparing said quantity of said first stream to a predetermined value or range of predetermined values.

  4. Development of the control and ignition systems on a high pressure gas turbine combustor

    Science.gov (United States)

    Valdez, Carlos Alejandro

    The ignition and control systems of a laboratory scale high-pressure gas turbine combustor were developed in the present work. This work provides a detailed description of the design, development and testing of the remote control system developed for a High Pressure Gas Turbine Combustor (HPTC). The combustor has the capability to operate at pressures up to 1.5 MPa and temperatures up to 2400 K. It is also designed for a maximum air and fuel flow rates of 81.93 g/s and 35.77 g/s respectively. The fuel used will be CH4 for the early experiments but it is designed to operate using a mixture of H2-CO with a hydrogen fuel composition variation of up to 30 percent. The HPTC also has optical accessibility capabilities in its combustion chamber with a converging nozzle that restricts the exhaust flow. It also has three circular ports that can be used as instrumentation ports to obtain real time data from the combustion chamber. LabVIEW was used as the controlling interface for the user. A detailed outline of the LabVIEW programming is also described. LabVIEW controlled the proportional valves (ball valves), and solenoid valves; it also provided the user with data from mass flow meters as well as pressure transducers. Both proportional and solenoid valves are 1.91 cm and can withstand pressures of up to 1551 kPa. Thermal mass flow meters were used to obtain the flow in the lines with a range from 200-1000 L/min with an accuracy of 1.5 percent. Pressure transducers with a range from 0 to 2068 kPa were also positioned on the lines in order to know the line pressures. The ignition system design, development and testing is also described with its integration to the High Pressure Gas Turbine Combustor. A modified spark plug was used to provide the igniter with an ignition source. A diffusion flame was used to ignite the main line using methane as the fuel that utilizes the air in the combustion chamber as the oxidizer. Testing included a functional test of the equipment, and

  5. Mercury emissions from municipal solid waste combustors

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    This report examines emissions of mercury (Hg) from municipal solid waste (MSW) combustion in the United States (US). It is projected that total annual nationwide MSW combustor emissions of mercury could decrease from about 97 tonnes (1989 baseline uncontrolled emissions) to less than about 4 tonnes in the year 2000. This represents approximately a 95 percent reduction in the amount of mercury emitted from combusted MSW compared to the 1989 mercury emissions baseline. The likelihood that routinely achievable mercury emissions removal efficiencies of about 80 percent or more can be assured; it is estimated that MSW combustors in the US could prove to be a comparatively minor source of mercury emissions after about 1995. This forecast assumes that diligent measures to control mercury emissions, such as via use of supplemental control technologies (e.g., carbon adsorption), are generally employed at that time. However, no present consensus was found that such emissions control measures can be implemented industry-wide in the US within this time frame. Although the availability of technology is apparently not a limiting factor, practical implementation of necessary control technology may be limited by administrative constraints and other considerations (e.g., planning, budgeting, regulatory compliance requirements, etc.). These projections assume that: (a) about 80 percent mercury emissions reduction control efficiency is achieved with air pollution control equipment likely to be employed by that time; (b) most cylinder-shaped mercury-zinc (CSMZ) batteries used in hospital applications can be prevented from being disposed into the MSW stream or are replaced with alternative batteries that do not contain mercury; and (c) either the amount of mercury used in fluorescent lamps is decreased to an industry-wide average of about 27 milligrams of mercury per lamp or extensive diversion from the MSW stream of fluorescent lamps that contain mercury is accomplished.

  6. Feasibility study of ultra-low NOx Gas turbine combustor using the RML combustion concept

    Energy Technology Data Exchange (ETDEWEB)

    Van, Tien Giap; Hwang, Jeong Jae; Kim, Min Kuk; Ahn, Kook Young [Environment and Energy Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon (Korea, Republic of)

    2016-12-15

    A new combustion concept, the so called RML, was investigated to validate its application as a gas turbine combustor for combustor outlet temperatures over 1973 K. The feasibility study of the RML combustor was conducted with zero dimensional combustion calculations. The emission characteristics of RQL, LEAN, EGR and RML combustors were compared. The calculation results showed that the RQL combustor has lower NOx emissions than the LEAN at high outlet temperature. NOx emissions of the RML combustor at equivalence ratio of the rich chamber of 2.0 can be reduced by 30 % compared with the EGR combustor, and lower than the RQL combustor at a combustor outlet temperature over 1973 K. However, the CO emissions of the RML combustor were higher than those of the LEAN and EGR combustors. Also, the possibility of applying the RML combustor to gas turbines was discussed considering residence time, equivalence ratio of the rich chamber and recirculation rate. Although further research to design and realize the proposed RML combustor is needed, this study verified that the RML concept can be successfully used in a gas turbine combustor.

  7. Variable volume combustor with an air bypass system

    Science.gov (United States)

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Ostebee, Heath Michael; Keener, Christopher Paul

    2017-02-07

    The present application provides a combustor for use with flow of fuel and a flow of air in a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles positioned within a liner and an air bypass system position about the liner. The air bypass system variably allows a bypass portion of the flow of air to bypass the micro-mixer fuel nozzles.

  8. Aerotrace. Measurement of particulates from an engine combustor

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, C.D. [DRA, Farnborough (United Kingdom)

    1997-12-31

    The effect of gas turbine operating conditions, inlet temperature, pressure and overall air fuel ratio, on particulate number density has been measured. Particulate number density was found to be proportional to combustor inlet pressure and decrease with increasing combustor inlet temperature. The relationship with air fuel ratio is more complex. The mechanism of particulate loss down sample lines has been elucidated and equations are presented to predict particulate losses for stainless steel and PTFE sample lines. (author) 3 refs.

  9. Combustion of Syngas Fuel in Gas Turbine Can Combustor

    OpenAIRE

    Chaouki Ghenai

    2010-01-01

    Numerical investigation of the combustion of syngas fuel mixture in gas turbine can combustor is presented in this paper. The objective is to understand the impact of the variability in the alternative fuel composition and heating value on combustion performance and emissions. The gas turbine can combustor is designed to burn the fuel efficiently, reduce the emissions, and lower the wall temperature. Syngas mixtures with different fuel compositions are produced through different coal and biom...

  10. Pollution technology program, can-annular combustor engines

    Science.gov (United States)

    Roberts, R.; Fiorentino, A. J.; Greene, W.

    1976-01-01

    A Pollution Reduction Technology Program to develop and demonstrate the combustor technology necessary to reduce exhaust emissions for aircraft engines using can-annular combustors is described. The program consisted of design, fabrication, experimental rig testing and assessment of results and was conducted in three program elements. The combustor configurations of each program element represented increasing potential for meeting the 1979 Environmental Protection Agency (EPA) emission standards, while also representing increasing complexity and difficulty of development and adaptation to an operational engine. Experimental test rig results indicate that significant reductions were made to the emission levels of the baseline JT8D-17 combustor by concepts in all three program elements. One of the Element I single-stage combustors reduced carbon monoxide to a level near, and total unburned hydrocarbons (THC) and smoke to levels below the 1979 EPA standards with little or no improvement in oxides of nitrogen. The Element II two-stage advanced Vorbix (vortex burning and mixing) concept met the standard for THC and achieved significant reductions in CO and NOx relative to the baseline. Although the Element III prevaporized-premixed concept reduced high power NOx below the Element II results, there was no improvement to the integrated EPA parameter relative to the Vorbix combustor.

  11. Basic neuron model electrical equivalent circuit: an undergraduate laboratory exercise.

    Science.gov (United States)

    Dabrowski, Katie M; Castaño, Diego J; Tartar, Jaime L

    2013-01-01

    We developed a hands-on laboratory exercise for undergraduate students in which they can build and manipulate a neuron equivalent circuit. This exercise uses electrical circuit components that resemble neuron components and are easy to construct. We describe the methods for creating the equivalent circuit and how to observe different neuron properties through altering the structure of the equivalent circuit. We explain how this hands-on laboratory activity allows for the better understanding of this fundamental neuroscience concept. At the conclusion of this laboratory exercise, undergraduate students will be able to apply the principles of Ohm's law, cable theory with regards to neurons, and understand the functions of resistance and capacitance in a neuron.

  12. The development of an ultra-low-emission gas-fired cyclonic combustor

    International Nuclear Information System (INIS)

    Xiong, Tian-yu; Khinkis, M.J.; Coppin, W.P.

    1991-01-01

    A gas-fired cyclonic combustor has been developed for relatively low-temperature direct-air heating applications that require ultra-low pollutant emissions. High-lean premixed combustion with a flame stabilizer is adopted to achieve ultra-low emissions and high turndown operation. On the basis of analytical studies and cold modeling, a 350-kW test combustor was designed and successfully tested. Experimental results obtained using natural gas and ambient air demonstrated that the test combustor can operate steadily at high excess air up to 80% to 100% over a large turndown range up to 40:1. At design operating conditions, NO x emissions as low as 0.6 vppm and CO and total hydrocarbon (THC) emissions below 3 vppm were achieved. Over the full operating range, NO x emissions from 0.3 to 1.0 vppm and CO and THC emissions below 4 vppm were demonstrated. In all tests, concentrations of NO 2 were less than 40% of the total NO x emissions -- lower than the level of NO 2 emissions from combustion processes required for good indoor air quality (0.5 vppm). This paper presents the concept of high-lean premixed ultra-low-emission cyclonic combustion, design specifications for the combustion system, and the major experimental results, including flame stability, emissions, and turndown performance. 13 refs., 12 figs., 1 tab

  13. The development of an ultra-low-emission gas-fired combustor for space heaters

    International Nuclear Information System (INIS)

    Xiong, Tian-yu; Khinkis, M.J.; Coppin, W.P.

    1991-01-01

    An ultra-low-emission as-fired combustor has been developed for relatively low-temperature direct-air heating applications. High-lean premixed cyclonic combustion with a flame stabilizer is employed to achieve ultra-low emissions and high turndown operation. On the basis of analytical studies and cold modeling a 350-kW test combustor was designed and successfully tested. Experimental results obtained using natural gas and ambient air demonstrated that the test combustor can operate steadily at high excess air up to 80% to 100% over a large turndown range up to 40:1. At design operating conditions, NO x emissions as low as 0.6 vppm and CO and total hydrocarbon (THC) emissions below 3 vppm were achieved. Over the full operating range, NO x emissions from 0.3 to 1.0 vppm and CO and THC emissions below 4 vppm were demonstrated. In all tests, concentrations of NO 2 were less than 40% of the total NO 2 emissions from combustion processes required for good indoor air quality (0.5 vppm). This paper presents the concept of high-lean premixed ultra-low-emission cyclonic combustion, design specifications for the combustion system, and the major experimental results, including flame stability, emissions, and turndown performance. 15 refs., 10 figs., 1 tab

  14. NASA One-Dimensional Combustor Simulation--User Manual for S1D_ML

    Science.gov (United States)

    Stueber, Thomas J.; Paxson, Daniel E.

    2014-01-01

    The work presented in this paper is to promote research leading to a closed-loop control system to actively suppress thermo-acoustic instabilities. To serve as a model for such a closed-loop control system, a one-dimensional combustor simulation composed using MATLAB software tools has been written. This MATLAB based process is similar to a precursor one-dimensional combustor simulation that was formatted as FORTRAN 77 source code. The previous simulation process requires modification to the FORTRAN 77 source code, compiling, and linking when creating a new combustor simulation executable file. The MATLAB based simulation does not require making changes to the source code, recompiling, or linking. Furthermore, the MATLAB based simulation can be run from script files within the MATLAB environment or with a compiled copy of the executable file running in the Command Prompt window without requiring a licensed copy of MATLAB. This report presents a general simulation overview. Details regarding how to setup and initiate a simulation are also presented. Finally, the post-processing section describes the two types of files created while running the simulation and it also includes simulation results for a default simulation included with the source code.

  15. Ignition and flame stabilization of a strut-jet RBCC combustor with small rocket exhaust.

    Science.gov (United States)

    Hu, Jichao; Chang, Juntao; Bao, Wen

    2014-01-01

    A Rocket Based Combined Cycle combustor model is tested at a ground direct connected rig to investigate the flame holding characteristics with a small rocket exhaust using liquid kerosene. The total temperature and the Mach number of the vitiated air flow, at exit of the nozzle are 1505 K and 2.6, respectively. The rocket base is embedded in a fuel injecting strut and mounted in the center of the combustor. The wall of the combustor is flush, without any reward step or cavity, so the strut-jet is used to make sure of the flame stabilization of the second combustion. Mass flow rate of the kerosene and oxygen injected into the rocket is set to be a small value, below 10% of the total fuel when the equivalence ratio of the second combustion is 1. The experiment has generated two different kinds of rocket exhaust: fuel rich and pure oxygen. Experiment result has shown that, with a relative small total mass flow rate of the rocket, the fuel rich rocket plume is not suitable for ignition and flame stabilization, while an oxygen plume condition is suitable. Then the paper conducts a series of experiments to investigate the combustion characteristics under this oxygen pilot method and found that the flame stabilization characteristics are different at different combustion modes.

  16. Dual-Pump CARS Thermometry and Species Concentration Measurements in a Supersonic Combustor

    Science.gov (United States)

    OByrne, Sean; Danehy, Paul M.; Cutler, Andrew D.

    2004-01-01

    The dual-pump coherent anti-Stokes Raman spectroscopy (CARS) method was used to measure temperature and the absolute mole fractions of N2, O2 and H2 in a supersonic combustor. Experiments were conducted in NASA Langley Research Center's Direct Connect Supersonic Combustion Test Facility. In this facility, hydrogen and air bum to increase the enthalpy of the test gas; O2 is then added to simulate air. This gas is expanded through a Mach 2 nozzle and into a combustor model consisting of a short constant-area section followed by a small rearward facing step and another constant area section. At the end of this straight section H2 fuel is then injected at Mach 2 and at 30 deg. angle with respect to the freestream. One wall of the duct then expands at a 3 deg. angle for over 1 meter. The ensuing combustion is monitored optically through ports in the side of the combustor. CARS measurements were performed at the nozzle exit and at four different planes downstream fuel injection. Maps were obtained of the mean temperature, as well as quantitative N2 and O2 and qualitative H2 mean mole fraction fields. Correlations between fluctuations of the different measured parameters are presented for one of the planes of data.

  17. Dual-Pump CARS Temperature and Species Concentration Measurements in a Supersonic Combustor

    Science.gov (United States)

    O'Byrne, S.; Danehy, P. M.; Tedder, S. A.; Cutler, A. D.

    2007-01-01

    The dual-pump coherent anti-Stokes Raman scattering (CARS) method was used to measure temperature and the mole fractions of N2 and O2 in a supersonic combustor. Experiments were conducted in NASA Langley Research Center s Direct Connect Supersonic Combustion Test Facility. In this facility, H2 and oxygen-enriched air burn to increase the enthalpy of the simulated air test gas. This gas is expanded through a Mach 2 nozzle and into a combustor model consisting of a short constant-area section followed by a small rearward-facing step and another constant-area section. At the end of this straight section, H2 fuel is injected at Mach 2 and at a 30 angle with respect to the freestream. One wall of the duct then expands at a 3 angle for over 1 meter. The ensuing combustion is probed optically through ports in the side of the combustor. Dual-pump CARS measurements were performed at the facility nozzle exit and at four planes downstream of fuel injection. Maps are presented of the mean temperature, as well as N2 and O2 mean mole fraction fields. Correlations between fluctuations of the different measured parameters are also presented.

  18. Effects of the reacting flowfield on combustion processes in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Gopalakrishnan, Priya

    The performance of dry, low NOx gas turbines, which employ lean premixed (or partially premixed) combustors, is often limited by static and dynamic combustor stability, and they require complicated mixing hardware. To overcome these issues, a novel design, referred to as a Stagnation Point Reverse Flow (SPRF) combustor, has been recently demonstrated. The SPRF combustor has been shown to operate with ultra low NOx emissions in premixed and nonpremixed modes with gaseous and liquid fuels. The objective of this thesis is to elucidate the interactions between the flowfield and combustion processes in this novel combustor for gas- and liquid-fueled operation. This is achieved with experimental measurements employing various optical diagnostic techniques, which include Particle Image Velocimetry (PIV), chemiluminescence imaging, Planar Laser-Induced Fluorescence (PLIF) of OH radicals and elastic laser scattering from liquid droplets. The velocity measurements obtained during gas-fueled operation show that both nonreacting and reacting flows exhibit a "stagnation" region with low mean velocity and high RMS fluctuations. In nonreacting flow, it has been shown that the decay rate of the jet can be modeled as a combination of a free jet and a jet in a uniform opposed flow. The high shear between the forward and reverse flows causes significant recirculation, resulting in enhanced entrainment and mixing of the returning hot product gases into the incoming reactant jet for the reacting flow cases, which enables stable operation of the combustor at very lean equivalence ratios. Nonpremixed operation produces a flowfield similar to that of the premixed case except in the near-field region. The coaxial injector design results in high turbulence intensities close to the injector exit leading to significant fuel-air premixing before combustion occurs. The operation of the SPRF combustor fueled with liquid Jet-A is also experimentally investigated. The results indicate that while

  19. A Model for Designing Adaptive Laboratory Evolution Experiments

    DEFF Research Database (Denmark)

    LaCroix, Ryan A.; Palsson, Bernhard O.; Feist, Adam M.

    2017-01-01

    The occurrence of mutations is a cornerstone of the evolutionary theory of adaptation, capitalizing on the rare chance that a mutation confers a fitness benefit. Natural selection is increasingly being leveraged in laboratory settings for industrial and basic science applications. Despite...

  20. The TriLab, a Novel ICT Based Triple Access Mode Laboratory Education Model

    Science.gov (United States)

    Abdulwahed, Mahmoud; Nagy, Zoltan K.

    2011-01-01

    This paper introduces a novel model of laboratory education, namely the TriLab. The model is based on recent advances in ICT and implements a three access modes to the laboratory experience (virtual, hands-on and remote) in one software package. A review of the three modes is provided with highlights of advantages and disadvantages of each mode.…

  1. Interview: partnering with the industry: the Olympic laboratory model.

    Science.gov (United States)

    Cowan, David A; Barker, Campbell P

    2012-07-01

    David A Cowan and Campbell P Barker speak to Ryan De Vooght-Johnson at Bioanalysis in May 2012 about the partnership between industry and academia for the setup and running of the doping-control laboratory for the London 2012 Olympic Games. David A Cowan is Director of the London 2012 anti-doping laboratory as well as Director of the King's College London Drug Control Centre, the UK's only WADA-accredited anti-doping laboratory, and Head of the Department of Forensic Science and Drug Monitoring. Cowan co-founded the Drug Control Centre in 1978 and became its Director in 1990. He has published extensively in the field of pharmaceutical analysis, especially as it relates to detecting drug administration in sport, and was awarded a personal chair in pharmaceutical toxicology in 1996. Cowan became Head of the Department of Forensic Science and Drug Monitoring at King's College London in 2002. He has served on a number of national and international committees, including the Council of Europe Working Party Investigating Drug Abuse in Sport that led to the first World Anti-Doping Convention, the Laboratory Representative on the International Olympic Committee's Medical Commission, and WADA's Laboratory Accreditation Subcommittee. He is a member of the Crippen Club for Distinguished Toxicologists. In 1998 he was awarded the IOC Trophy for Sport Ethics by the BOA. He was a founding member of the World Association of Anti-Doping Scientists and became its first President serving on its Executive Board between 2001 and 2004. He was a Visiting Laboratory Director at the Salt Lake City Winter Olympic Games 2002, where the first novel erythropoiesis-stimulating protein (NESP) positive was discovered. He was also a senior advisory scientist at both the Turin Winter Olympic Games in 2006 and the Beijing Olympic Games in 2008. He was also a member of the IOC Medical Commission for the Sydney Olympic Games in 2000 and the Vancouver Winter Olympic Games in 2010. The Drug Control

  2. Flow conditioner for fuel injector for combustor and method for low-NO.sub.x combustor

    Science.gov (United States)

    Dutta, Partha; Smith, Kenneth O.; Ritz, Frank J.

    2013-09-10

    An injector for a gas turbine combustor including a catalyst coated surface forming a passage for feed gas flow and a channel for oxidant gas flow establishing an axial gas flow through a flow conditioner disposed at least partially within an inner wall of the injector. The flow conditioner includes a length with an interior passage opening into upstream and downstream ends for passage of the axial gas flow. An interior diameter of the interior passage smoothly reduces and then increases from upstream to downstream ends.

  3. Astrophysical radiative shocks: From modeling to laboratory experiments

    Czech Academy of Sciences Publication Activity Database

    Gonzales, N.; Stehlé, C.; Audit, E.; Busquet, M.; Rus, Bedřich; Thais, F.; Acef, O.; Barroso, P.; Bar-Shalom, A.; Bauduin, D.; Kozlová, Michaela; Lery, T.; Madouri, A.; Mocek, Tomáš; Polan, Jiří

    2006-01-01

    Roč. 24, - (2006), s. 535-540 ISSN 0263-0346 EU Projects: European Commission(XE) 506350 - LASERLAB-EUROPE; European Commission(XE) 5592 - JETSET Grant - others:CNRS(FR) PNPS Institutional research plan: CEZ:AV0Z10100523 Keywords : laboratory astrophysics * laser plasmas * radiative shock waves * radiative transfer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.958, year: 2006

  4. Development of New, Low-Head Hydropower Turbine - Modeling & Laboratory Test DE-EE0005426

    Energy Technology Data Exchange (ETDEWEB)

    Krouse, Wayne [Hydro Green Energy, Westmont, IL (United States)

    2014-12-05

    Hydro Green Energy, LLC (HGE) will complete the design, fabrication and laboratory testing of a scaled, vertically stackable, low-head hydropower turbine called the Modular Bulb Turbine (MBT). HGE will also complete a summary report that includes the laboratory testing results and analysis of the tests. Project Goals: Design, model and test modular bulb turbine for installation in numerous HGE low-head hydropower projects at non-powered USACE dams. Project Results: The sub-scale prototype was tested successfully at a leading US hydraulic laboratory. Laboratory data results agreed well with predicted results from numerical modeling.

  5. Investigation on the flame dynamics of meso-combustors

    Science.gov (United States)

    Ahmed, Mahbub

    Miniature heat engines burning hydrogen and hydrocarbon fuels have significantly higher energy densities compared to conventional lithium batteries and thus will play an essential role in the portable production of power for future electronics, remote sensors, and micro aerial vehicles. Additionally, miniature heat engines will tremendously benefit next generation of environmental technologies such as steam reforming, ammonia decomposition and fuel cells. Successful miniaturization of heat engine components demand a more complete and broader understanding of micro-fluid dynamics and micro-combustion phenomena associated with the combustor design. This dissertation is aimed at investigating the details of the micro-mixing dynamics and the combustion behavior of the meso-combustor and to create fundamental understanding of physics based design methodology. The primary goals of the project are (i) to develop an understanding of fuel-air mixing inside a meso-combustor, (ii) to develop an understanding of the flame stability (flame quenching and velocity blowout) criteria of a meso-combustor, (iii) to understand the thermal behavior of the meso-combustor, and (iv) to correlate these with combustor operating conditions such as the Reynolds number, equivalent ratio, and thermal power etc. The present study shows that adequate mixing of fuel and air is achievable in millimeter scale combustors. Both computed results and experimental measurements of iso-thermal (non-burning) flows at different mixing configurations indicate that the laminar burning velocity remains higher than the local flow velocities in most of the combustor locations to support stable flame propagations. Stable flames of hydrogen are achieved for all mixing and flow configurations. The combustion of methane with air as oxidizer in the combustors is unreliable. However, highly stable combustion of methane at various mixing and flow conditions is achieved when pure oxygen is used as an oxidizer. The

  6. Using a Logic Model to Evaluate Undergraduate Instruction in a Laboratory Preschool

    Science.gov (United States)

    Monroe, Lisa; Horm, Diane M.

    2012-01-01

    Research Findings: Utilization-focused, process evaluations of university-based laboratory preschools in their role with teacher preparation programs are rare in the current literature. This paper describes a self-study evaluation designed and implemented at a university laboratory preschool. A theory approach logic model was developed and used to…

  7. Hairy Root as a Model System for Undergraduate Laboratory Curriculum and Research

    Science.gov (United States)

    Keyes, Carol A.; Subramanian, Senthil; Yu, Oliver

    2009-01-01

    Hairy root transformation has been widely adapted in plant laboratories to rapidly generate transgenic roots for biochemical and molecular analysis. We present hairy root transformations as a versatile and adaptable model system for a wide variety of undergraduate laboratory courses and research. This technique is easy, efficient, and fast making…

  8. Modeling and Testing of EVs - Preliminary Study and Laboratory Development

    DEFF Research Database (Denmark)

    Yang, Guang-Ya; Marra, Francesco; Nielsen, Arne Hejde

    2010-01-01

    Electric vehicles (EVs) are expected to play a key role in the future energy management system to stabilize both supply and consumption with the presence of high penetration of renewable generation. A reasonably accurate model of battery is a key element for the study of EVs behavior and the grid...... tests, followed by the suggestions towards a feasible battery model for further studies.......Electric vehicles (EVs) are expected to play a key role in the future energy management system to stabilize both supply and consumption with the presence of high penetration of renewable generation. A reasonably accurate model of battery is a key element for the study of EVs behavior and the grid...... impact at different geographical areas, as well as driving and charging patterns. Electric circuit model is deployed in this work to represent the electrical properties of a lithium-ion battery. This paper reports the preliminary modeling and validation work based on manufacturer data sheet and realistic...

  9. Advanced low emissions catalytic combustor program at General Electric

    Science.gov (United States)

    Dodds, W. J.

    1979-01-01

    The Advanced Low Emissions Catalytic Combustors Program (ALECC) is being undertaken to evaluate the feasibility of employing catalytic combustion technology in aircraft gas turbine engines as a means to control emission of oxides of nitrogen during subsonic stratospheric cruise operation. The ALECC Program is being conducted in three phases. The first phase, which was completed in November, 1978, consisted of a design study to identify catalytic combustor designs having the greatest potential to meet the emissions and performance goals specified. The primary emissions goal of this program was to obtain cruise NO emissions of less than 1g/kg (compared with levels of 15 to 20 g/x obtained with current designs)/ However, good overall performance and feasibility for engine development were heavily weighted in the evaluation of combustor designs.

  10. Design and evaluation of combustors for reducing aircraft engine pollution

    Science.gov (United States)

    Jones, R. E.; Grobman, J.

    1973-01-01

    Various techniques and test results are briefly described and referenced for detail. The effort arises from the increasing concern for the measurement and control of emissions from gas turbine engines. The greater part of this research is focused on reducing the oxides of nitrogen formed during takeoff and cruise in both advanced CTOL, high pressure ratio engines, and advanced supersonic aircraft engines. The experimental approaches taken to reduce oxides of nitrogen emissions include the use of: multizone combustors incorporating reduced dwell time, fuel-air premixing, air atomization, fuel prevaporization, water injection, and gaseous fuels. In the experiments conducted to date, some of these techniques were more successful than others in reducing oxides of nitrogen emissions. Tests are being conducted on full-annular combustors at pressures up to 6 atmospheres and on combustor segments at pressures up to 30 atmospheres.

  11. Analytical fuel property effects: Small combustors, phase 2

    Science.gov (United States)

    Hill, T. G.; Monty, J. D.; Morton, H. L.

    1985-01-01

    The effects of non-standard aviation fuels on a typical small gas turbine combustor were studied and the effectiveness of design changes intended to counter the effects of these fuels was evaluated. The T700/CT7 turboprop engine family was chosen as being representative of the class of aircraft power plants desired for this study. Fuel properties, as specified by NASA, are characterized by low hydrogen content and high aromatics levels. No. 2 diesel fuel was also evaluated in this program. Results demonstrated the anticipated higher than normal smoke output and flame radiation intensity with resulting increased metal temperatures on the baseline T700 combustor. Three new designs were evaluated using the non standard fuels. The three designs incorporated enhanced cooling features and smoke reduction features. All three designs, when burning the broad specification fuels, exhibited metal temperatures at or below the baseline combustor temperatures on JP-5. Smoke levels were acceptable but higher than predicted.

  12. Combustor with two stage primary fuel assembly

    Science.gov (United States)

    Sharifi, Mehran; Zolyomi, Wendel; Whidden, Graydon Lane

    2000-01-01

    A combustor for a gas turbine having first and second passages for pre-mixing primary fuel and air supplied to a primary combustion zone. The flow of fuel to the first and second pre-mixing passages is separately regulated using a single annular fuel distribution ring having first and second row of fuel discharge ports. The interior portion of the fuel distribution ring is divided by a baffle into first and second fuel distribution manifolds and is located upstream of the inlets to the two pre-mixing passages. The annular fuel distribution ring is supplied with fuel by an annular fuel supply manifold, the interior portion of which is divided by a baffle into first and second fuel supply manifolds. A first flow of fuel is regulated by a first control valve and directed to the first fuel supply manifold, from which the fuel is distributed to first fuel supply tubes that direct it to the first fuel distribution manifold. From the first fuel distribution manifold, the first flow of fuel is distributed to the first row of fuel discharge ports, which direct it into the first pre-mixing passage. A second flow of fuel is regulated by a second control valve and directed to the second fuel supply manifold, from which the fuel is distributed to second fuel supply tubes that direct it to the second fuel distribution manifold. From the second fuel distribution manifold, the second flow of fuel is distributed to the second row of fuel discharge ports, which direct it into the second pre-mixing passage.

  13. Variable volume combustor with aerodynamic fuel flanges for nozzle mounting

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-20

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and for providing the flow of fuel therethrough. The fuel injection system also may include a number of aerodynamic fuel flanges connecting the micro-mixer fuel nozzles and the support struts.

  14. Exploring a Laboratory Model of Pharmacogenetics as Applied to Clinical Decision Making

    Directory of Open Access Journals (Sweden)

    David F. Kisor

    2013-01-01

    Full Text Available Objective: To evaluate a pilot of a laboratory model for relating pharmacogenetics to clinical decision making. Case Study: This pilot was undertaken and evaluated to help determine if a pharmacogenetics laboratory should be included in the core Doctor of Pharmacy curriculum. The placement of the laboratory exercise in the curriculum was determined by identifying the point in the curriculum where the students had been introduced to the chemistry of deoxyribonucleic acid (DNA as well as instructed on the chemistry of genetic variation. The laboratory included cytochrome P450 2C19 genotyping relative to the *2 variant. Twenty-four students served as the pilot group. Students provided buccal swabs as the source of DNA. Students stabilized the samples and were then provided instructions related to sample preparation, polymerase chain reaction, and gel electrophoresis. The results were reported as images of gels. Students used a reference gel image to compare their results to. Students then applied a dosing algorithm to make a "clinical decision" relative to clopidogrel use. Students were offered a post laboratory survey regarding attitudes toward the laboratory. Twenty-four students completed the laboratory with genotyping results being provided for 22 students (91.7%. Sixteen students were wild-type (*1/*1, while six students were heterozygous (*1/*2. Twenty-three students (96% completed the post laboratory survey. All 23 agreed (6, 26.1% or strongly agreed (17, 73.9% that the laboratory "had relevance and value in the pharmacy curriculum" Conclusion: The post pilot study survey exploring a laboratory model for pharmacogenetics related to clinical decision making indicated that such a laboratory would be viewed positively by students. This model may be adopted by colleges to expand pharmacogenetics education.   Type: Case Study

  15. Large eddy simulation of premixed and non-premixed combustion in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Undapalli, Satish

    A new combustor referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet the increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high stability in both premixed and non-premixed modes. The objective of this thesis work is to perform Large Eddy Simulations (LES) on this lab-scale combustor and elucidate the underlying physics that has resulted in its excellent performance. To achieve this, numerical simulations have been performed in both the premixed and non-premixed combustion modes, and velocity field, species field, entrainment characteristics, flame structure, emissions, and mixing characteristics have been analyzed. Simulations have been carried out first for a non-reactive case to resolve relevant fluid mechanics without heat release by the computational grid. The computed mean and RMS quantities in the non-reacting case compared well with the experimental data. Next, the simulations were extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures: Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Results from the EBU and TF models exhibit reasonable agreement with the experimental velocity field. However, the computed thermal and species fields have noticeable discrepancies. Only LEM with LES (LEMLES), which is an advanced scalar approach, has been able to accurately predict both the velocity and species fields. Scalar mixing plays an important role in combustion, and this is solved directly at the sub-grid scales in LEM. As a result, LEM accurately predicts the scalar fields. Due to the two way coupling between the super-grid and sub-grid quantities, the velocity predictions also compare very well with the experiments. In other approaches, the sub-grid effects have been either modeled using conventional approaches (EBU) or need

  16. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2013-12-24

    A combustor cap assembly for a turbine engine includes a combustor cap and a plurality of fuel nozzles mounted on the combustor cap. One or more of the fuel nozzles would include two separate fuel circuits which are individually controllable. The combustor cap assembly would be controlled so that individual fuel circuits of the fuel nozzles are operated or deliberately shut off to provide for physical separation between the flow of fuel delivered by adjacent fuel nozzles and/or so that adjacent fuel nozzles operate at different pressure differentials. Operating a combustor cap assembly in this fashion helps to reduce or eliminate the generation of undesirable and potentially harmful noise.

  17. Model Virtual Laboratory Fisika Modern untuk Meningkatkan Disposisi Berpikir Kritis Calon Guru

    OpenAIRE

    Gunawan, Gunawan; Liliasari, Liliasari

    2012-01-01

    : Model Virtual Laboratory Modern Physics to Increase Pre-Service Teachers' Critical Disposition. This study was aimed to reveal the effectiveness of the modern physics virtual laboratory model on the students critical thinking disposition. Sixty-four students divided into two groups, the experimental and control groups, were involved in this study. An instrument used to test the students' critical thinking disposition was utilized, integrated with the mastery of modern physics concepts. The ...

  18. Testing of DLR C/C-SiC and C/C for HIFiRE 8 Scramjet Combustor

    Science.gov (United States)

    Glass, David E.; Capriotti, Diego P.; Reimer, Thomas; Kutemeyer, Marius; Smart, Michael K.

    2014-01-01

    Ceramic Matrix Composites (CMCs) have been proposed for use as lightweight hot structures in scramjet combustors. Previous studies have calculated significant weight savings by utilizing CMCs (active and passive) versus actively cooled metallic scramjet structures. Both a carbon/carbon (C/C) and a carbon/carbon-silicon carbide (C/C-SiC) material fabricated by DLR (Stuttgart, Germany) are being considered for use in a passively cooled combustor design for Hypersonic International Flight Research Experimentation (HIFiRE) 8, a joint Australia / Air Force Research Laboratory hypersonic flight program, expected to fly at Mach 7 for approximately 30 sec, at a dynamic pressure of 55 kilopascals. Flat panels of the DLR C/C and C/C-SiC materials were installed downstream of a hydrogen-fueled, dual-mode scramjet combustor and tested for several minutes at conditions simulating flight at Mach 5 and Mach 6. Gaseous hydrogen fuel was used to fuel the scramjet combustor. The test panels were instrumented with embedded Type K and Type S thermocouples. Zirconia felt insulation was used during some of the tests to reduce heat loss from the back surface and thus increase the heated surface temperature of the C/C-SiC panel approximately 177 C (350 F). The final C/C-SiC panel was tested for three cycles totaling over 135 sec at Mach 6 enthalpy. Slightly more erosion was observed on the C/C panel than the C/C-SiC panels, but both material systems demonstrated acceptable recession performance for the HIFiRE 8 flight.

  19. Amphibians as animal models for laboratory research in physiology.

    Science.gov (United States)

    Burggren, Warren W; Warburton, Stephen

    2007-01-01

    The concept of animal models is well honored, and amphibians have played a prominent part in the success of using key species to discover new information about all animals. As animal models, amphibians offer several advantages that include a well-understood basic physiology, a taxonomic diversity well suited to comparative studies, tolerance to temperature and oxygen variation, and a greater similarity to humans than many other currently popular animal models. Amphibians now account for approximately 1/4 to 1/3 of lower vertebrate and invertebrate research, and this proportion is especially true in physiological research, as evident from the high profile of amphibians as animal models in Nobel Prize research. Currently, amphibians play prominent roles in research in the physiology of musculoskeletal, cardiovascular, renal, respiratory, reproductive, and sensory systems. Amphibians are also used extensively in physiological studies aimed at generating new insights in evolutionary biology, especially in the investigation of the evolution of air breathing and terrestriality. Environmental physiology also utilizes amphibians, ranging from studies of cryoprotectants for tissue preservation to physiological reactions to hypergravity and space exploration. Amphibians are also playing a key role in studies of environmental endocrine disruptors that are having disproportionately large effects on amphibian populations and where specific species can serve as sentinel species for environmental pollution. Finally, amphibian genera such as Xenopus, a genus relatively well understood metabolically and physiologically, will continue to contribute increasingly in this new era of systems biology and "X-omics."

  20. Spatially-resolved measurements of soot size and population in a swirl-stabilized combustor

    OpenAIRE

    Wood, CP; Smith, RA; Samuelsen, GS

    1985-01-01

    Isooctane, and mixtures of isooctane with various ring and aromatic compounds blended to yield the same smoke point were separately injected through a twin-fluid atomizer into a turbulent, swirl-stabilized model combustor. A nonintrusive optical probe based on larege angle (60°, 20°) intensity ratio scattering was used to yield a point measurement of soot particulate in the size range of 0.08 to 0.38 μm. The velocity and temperature fields were characterized by a two-color laser anemometer an...

  1. Thermo-hydrodynamic design of fluidized bed combustors estimating metal wastage

    CERN Document Server

    Lyczkowski, Robert W; Bouillard, Jacques X; Folga, Stephen M

    2012-01-01

    Thermo-Hydrodynamic Design of Fluidized Bed Combustors: Estimating Metal Wastage is a unique volume that finds that the most sensitive parameters affecting metal wastage are superficial fluidizing velocity, particle diameter, and particle sphericity.  Gross consistencies between disparate data sources using different techniques were found when the erosion rates are compared on the same basis using the concept of renormalization.  The simplified mechanistic models and correlations, when validated, can be used to renormalize any experimental data so they can be compared on a consistent basis using a master equation.

  2. Thermal performance of a micro-combustor for micro-gas turbine system

    International Nuclear Information System (INIS)

    Cao, H.L.; Xu, J.L.

    2007-01-01

    Premixed combustion of hydrogen gas and air was performed in a stainless steel based micro-annular combustor for a micro-gas turbine system. Micro-scale combustion has proved to be stable in the micro-combustor with a gap of 2 mm. The operating range of the micro-combustor was measured, and the maximum excess air ratio is up to 4.5. The distribution of the outer wall temperature and the temperature of exhaust gas of the micro-combustor with excess air ratio were obtained, and the wall temperature of the micro-combustor reaches its maximum value at the excess air ratio of 0.9 instead of 1 (stoichiometric ratio). The heat loss of the micro-combustor to the environment was calculated and even exceeds 70% of the total thermal power computed from the consumed hydrogen mass flow rate. Moreover, radiant heat transfer covers a large fraction of the total heat loss. Measures used to reduce the heat loss were proposed to improve the thermal performance of the micro-combustor. The optimal operating status of the micro-combustor and micro-gas turbine is analyzed and proposed by analyzing the relationship of the temperature of the exhaust gas of the micro-combustor with thermal power and excess air ratio. The investigation of the thermal performance of the micro-combustor is helpful to design an improved micro-combustor

  3. The Instituto de Investigaciones Electricas fluidized bed combustor; El combustor de lecho fluidizado del Instituto de Investigaciones Electricas

    Energy Technology Data Exchange (ETDEWEB)

    Milan Foressi, Julio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    After synthesizing the most important aspects of the combustion technology in fluidized bed, the experimental combustor developed at the Instituto de Investigaciones Electricas (IIE) is described, as well as the test results of the experiences carried out with coal from Rio Escondido, Coahuila. [Espanol] Tras sintetizar los aspectos mas importantes de la tecnologia de combustion en lecho fluidizado, se describe el combustor experimental desarrollado en el Instituto de Investigaciones Electricas (IIE), asi como los resultados de las experiencias realizadas con carbon proveniente de Rio Escondido, Coahuila.

  4. Imaging and Modeling Laboratory in Neurobiology and Oncology - IMNC. Activity report 2008-2012

    International Nuclear Information System (INIS)

    Charon, Yves; Arlaud, Nathalie; Mastrippolito, Roland

    2014-09-01

    The Imaging and Modeling Laboratory in Neurobiology and Oncology (IMNC) is an interdisciplinary unit shared between the Paris-Sud and Paris-Diderot universities and the National Institute of Nuclear and particle physics (IN2P3). Created in January 2006, the laboratory activities are structured around three main topics: the clinical and pre-clinical multi-modal imaging (optical and isotopic), the modeling of tumoral processes, and radiotherapy. This report presents the activities of the laboratory during the years 2008-2012: 1 - Forewords; 2 - Highlights; 3 - Research teams: Small animal imaging; Metabolism, imaging and olfaction; Surgery imaging in oncology; Quantification in molecular imaging; Modeling of biological systems; 4 - Technical innovations: Instrumentation, Scientific calculation, Biology department, valorisation and open-source softwares; 5 - Publications; 6 - Scientific life, communication and teaching activities; 7 - Laboratory operation; 8 - Perspectives

  5. Evaporation of J13 water: laboratory experiments and geochemical modeling

    International Nuclear Information System (INIS)

    Dibley, M.J.; Knauss, K.G.; Rosenberg, N.D.

    1999-01-01

    We report results from experiments on the evaporative chemical evolution of synthetic J13 water, representative of water from well J13, a common reference water in the Yucca Mountain Project. Data include anion and cation analysis and qualitative mineral identification for a series of open system experiments, with and without crushed tuff present, conducted at sub-boiling temperatures. Ca and Mg precipitated readily as carbonates and anions Cl, F, NO 3 and SO 4 remained in solution in nearly identical ratios. The pH stabilized at about 10. After ∼ 1000x concentration, the minerals formed were amorphous silica, aragonite and calcite. The presence of tuff appears to have very little effect on the relative distribution of the anions in solution, except for possibly F, which had a relatively lower concentration ratio. The Si was lower in the solutions with tuff present suggesting that the tuff enhances SiO 2 precipitation. Even though the tools to model highly-concentrated salt solutions are limited, we compare our experimental results with the results of geochemical models, with (perhaps) surprising good results. In response to different assumed CO 2 levels, pH varied, but anion concentrations were not greatly affected

  6. Solid modeling research at Lawrence Livermore National Laboratory: 1982-1985

    International Nuclear Information System (INIS)

    Kalibjian, J.R.

    1985-01-01

    The Lawrence Livermore National Laboratory has sponsored solid modeling research for the past four years to assess this new technology and to determine its potential benefits to the Nuclear Weapons Complex. We summarize here the results of five projects implemented during our effort. First, we have installed two solid modeler codes, TIPS-1 (Technical Information Processing System-1) and PADL-2 (Part and Assembly Description Language), on the Laboratory's CRAY-1 computers. Further, we have extended the geometric coverage and have enhanced the graphics capabilities of the TIPS-1 modeler. To enhance solid modeler performance on our OCTOPUS computer system, we have also developed a method to permit future use of the Laboratory's network video system to provide high-resolution, shaded images at users' locations. Finally, we have begun to implement code that will link solid-modeler data bases to finite-element meshing codes

  7. DEVELOPMENT OF A VORTEX CONTAINMENT COMBUSTOR FOR COAL COMBUSTION SYTEMS

    Science.gov (United States)

    The report describes the development of a vortex containment combustor (VCC) for coal combustion systems, designed to solve major problems facing the conversion of oil- and gas-fired boilers to coal (e.g., derating, inorganic impurities in coal, and excessive formation of NOx and...

  8. Non-linear dynamics in pulse combustor: A review

    Indian Academy of Sciences (India)

    tages, lack of thorough understanding of the dynamics complicates the design of pulse combustors and is one of the main ... engineering community. Many researchers have investigated the dynamic behaviour of .... substantiated the qualitative observations similar to that in figure 1 with quantitative esti- mates based on ...

  9. Utilisation of low grade fuels influidised bed combustors

    CSIR Research Space (South Africa)

    North, B

    2010-11-01

    Full Text Available This presentation highlights the utilisation of low grade fuels in Fluidised Bed Combustors (FBC) with regards to South African coal. It looks at types of coals and fuels tested, test facilities and examples of FBC’s at the CSIR. Benefits from...

  10. Inventory of data bases, graphics packages, and models in Department of Energy laboratories

    International Nuclear Information System (INIS)

    Shriner, C.R.; Peck, L.J.

    1978-11-01

    A central inventory of energy-related environmental bibliographic and numeric data bases, graphics packages, integrated hardware/software systems, and models was established at Oak Ridge National Laboratory in an effort to make these resources at Department of Energy (DOE) laboratories better known and available to researchers and managers. This inventory will also serve to identify and avoid duplication among laboratories. The data were collected at each DOE laboratory, then sent to ORNL and merged into a single file. This document contains the data from the merged file. The data descriptions are organized under major data types: data bases, graphics packages, integrated hardware/software systems, and models. The data include descriptions of subject content, documentation, and contact persons. Also provided are computer data such as media on which the item is available, size of the item, computer on which the item executes, minimum hardware configuration necessary to execute the item, software language(s) and/or data base management system utilized, and character set used. For the models, additional data are provided to define the model more accurately. These data include a general statement of algorithms, computational methods, and theories used by the model; organizations currently using the model; the general application area of the model; sources of data utilized by the model; model validation methods, sensitivity analysis, and procedures; and general model classification. Data in this inventory will be available for on-line data retrieval on the DOE/RECON system

  11. Attempt to model laboratory-scale diffusion and retardation data

    Science.gov (United States)

    Hölttä, P.; Siitari-Kauppi, M.; Hakanen, M.; Tukiainen, V.

    2001-02-01

    Different approaches for measuring the interaction between radionuclides and rock matrix are needed to test the compatibility of experimental retardation parameters and transport models used in assessing the safety of the underground repositories for the spent nuclear fuel. In this work, the retardation of sodium, calcium and strontium was studied on mica gneiss, unaltered, moderately altered and strongly altered tonalite using dynamic fracture column method. In-diffusion of calcium into rock cubes was determined to predict retardation in columns. In-diffusion of calcium into moderately and strongly altered tonalite was interpreted using a numerical code FTRANS. The code was able to interprete in-diffusion of weakly sorbing calcium into the saturated porous matrix. Elution curves of calcium for the moderately and strongly altered tonalite fracture columns were explained adequately using FTRANS code and parameters obtained from in-diffusion calculations. In this paper, mass distribution ratio values of sodium, calcium and strontium for intact rock are compared to values, previously obtained for crushed rock from batch and crushed rock column experiments. Kd values obtained from fracture column experiments were one order of magnitude lower than Kd values from batch experiments.

  12. An Experimental Investigation of Self-Excited Combustion Dynamics in a Single Element Lean Direct Injection (LDI) Combustor

    Science.gov (United States)

    Gejji, Rohan M.

    The management of combustion dynamics in gas turbine combustors has become more challenging as strict NOx/CO emission standards have led to engine operation in a narrow, lean regime. While premixed or partially premixed combustor configurations such as the Lean Premixed Pre-vaporized (LPP), Rich Quench Lean burn (RQL), and Lean Direct Injection (LDI) have shown a potential for reduced NOx emissions, they promote a coupling between acoustics, hydrodynamics and combustion that can lead to combustion instabilities. These couplings can be quite complex, and their detailed understanding is a pre-requisite to any engine development program and for the development of predictive capability for combustion instabilities through high-fidelity models. The overarching goal of this project is to assess the capability of high-fidelity simulation to predict combustion dynamics in low-emissions gas turbine combustors. A prototypical lean-direct-inject combustor was designed in a modular configuration so that a suitable geometry could be found by test. The combustor comprised a variable length air plenum and combustion chamber, air swirler, and fuel nozzle located inside a subsonic venturi. The venturi cross section and the fuel nozzle were consistent with previous studies. Test pressure was 1 MPa and variables included geometry and acoustic resonance, inlet temperatures, equivalence ratio, and type of liquid fuel. High-frequency pressure measurements in a well-instrumented metal chamber yielded frequencies and mode shapes as a function of inlet air temperature, equivalence ratio, fuel nozzle placement, and combustor acoustic resonances. The parametric survey was a significant effort, with over 105 tests on eight geometric configurations. A good dataset was obtained that could be used for both operating-point-dependent quantitative comparisons, and testing the ability of the simulation to predict more global trends. Results showed a very strong dependence of instability amplitude on

  13. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

    Science.gov (United States)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  14. Large Eddy Simulation of a Swirl-Stabilized Pilot Combustor from Conventional to Flameless Mode

    Directory of Open Access Journals (Sweden)

    Ehsan Fooladgar

    2016-01-01

    Full Text Available This paper investigates flame and flow structure of a swirl-stabilized pilot combustor in conventional, high temperature, and flameless modes by means of a partially stirred reactor combustion model to provide a better insight into designing lean premixed combustion devices with preheating system. Finite rate chemistry combustion model with one step tuned mechanism and large eddy simulation is used to numerically simulate six cases in these modes. Results show that moving towards high temperature mode by increasing the preheating level, the combustor is prone to formation of thermal NOx with higher risks of flashback. In addition, the flame becomes shorter and thinner with higher turbulent kinetic energies. On the other hand, towards the flameless mode, leaning the preheated mixture leads to almost thermal NOx-free combustion with lower risk of flashback and thicker and longer flames. Simulations also show qualitative agreements with available experiments, indicating that the current combustion model with one step tuned mechanisms is capable of capturing main features of the turbulent flame in a wide range of mixture temperature and equivalence ratios.

  15. Shock-tunnel combustor testing for hypersonic vehicles

    Science.gov (United States)

    Loomis, Mark P.

    1994-01-01

    Proposed configurations for the next generation of transatmospheric vehicles will rely on air breathing propulsion systems during all or part of their mission. At flight Mach numbers greater than about 7 these engines will operate in the supersonic combustion ramjet mode (scramjet). Ground testing of these engine concepts above Mach 8 requires high pressure, high enthalpy facilities such as shock tunnels and expansion tubes. These impulse, or short duration facilities have test times on the order of a millisecond, requiring high speed instrumentation and data systems. One such facility ideally suited for scramjet testing is the NASA-Ames 16-Inch shock tunnel, which over the last two years has completed a series of tests for the NASP (National Aero-Space Plane) program at simulated flight Mach numbers ranging from 12-16. The focus of the experimental programs consisted of a series of classified tests involving a near-full scale hydrogen fueled scramjet combustor model in the semi-free jet method of engine testing whereby the compressed forebody flow ahead of the cowl inlet is reproduced (see appendix A). The AIMHYE-1 (Ames Integrated Modular Hypersonic Engine) test entry for the NASP program was completed in April 1993, while AIMHYE-2 was completed in May 1994. The test entries were regarded as successful, resulting in some of the first data of its kind on the performance of a near full scale scramjet engine at Mach 12-16. The data was distributed to NASP team members for use in design system verification and development. Due to the classified nature of the hardware and data, the data reports resulting from this work are classified and have been published as part of the NASP literature. However, an unclassified AIAA paper resulted from the work and has been included as appendix A. It contains an overview of the test program and a description of some of the important issues.

  16. Design and fabrication of a meso-scale stirling engine and combustor.

    Energy Technology Data Exchange (ETDEWEB)

    Echekki, Tarek (Sandia National Laboratories, Livermore, CA); Haroldsen, Brent L. (Sandia National Laboratories, Livermore, CA); Krafcik, Karen L. (Sandia National Laboratories, Livermore, CA); Morales, Alfredo Martin (Sandia National Laboratories, Livermore, CA); Mills, Bernice E. (Sandia National Laboratories, Livermore, CA); Liu, Shiling (Sandia National Laboratories, Livermore, CA); Lee, Jeremiah C. (Sandia National Laboratories, Livermore, CA); Karpetis, Adionos N. (Sandia National Laboratories, Livermore, CA); Chen, Jacqueline H. (Sandia National Laboratories, Livermore, CA); Ceremuga, Joseph T. (Sandia National Laboratories, Livermore, CA); Raber, Thomas N. (Sandia National Laboratories, Livermore, CA); Hekmuuaty, Michelle A. (Sandia National Laboratories, Livermore, CA)

    2005-05-01

    prototypes to verify the design. A final high precision engine was created via LIGA. The micro-combustor was based on an excess enthalpy concept. Development of a micro-combustor included both modeling and experiments. We developed a suite of simulation tools both in support of the design of the prototype combustors, and to investigate more fundamental aspects of combustion at small scales. Issues of heat management and integration with the micro-scale Stirling engine were pursued using CFD simulations. We found that by choice of the operating conditions and channel dimensions energy conversion occurs by catalysis-dominated or catalysis-then-homogeneous phase combustion. The purpose of the experimental effort in micro-combustion was to study the feasibility and explore the design parameters of excess enthalpy combustors. The efforts were guided by the necessity for a practical device that could be implemented in a miniature power generator, or as a stand-alone device used for heat generation. Several devices were fabricated and successfully tested using methane as the fuel.

  17. Model Virtual Laboratory Fisika Modern Untuk Meningkatkan Keterampilan Generik Sains Calon Guru

    OpenAIRE

    Gunawan, Gunawan; Setiawan, Agus; Widyantoro, Dwi H

    2013-01-01

    : We have developed a virtual laboratory for teaching modern physics. The purpose of this study is to examine the effectiveness of a virtual laboratory model of modern physics on students' generic science skills. The study involved 64 students who were divided into two groups, the experimental group and control group. The research instrument used a generic science skills test that is integrated with the mastery of concepts of modern physics. Data were analyzed by using mean-difference test an...

  18. Development of an advanced high efficiency coal combustor for boiler retrofit. Task 1, Cold flow burner development: Final report

    Energy Technology Data Exchange (ETDEWEB)

    LaFlesh, R.C.; Rini, M.J.; McGowan, J.G.

    1989-10-01

    The overall objective of this program is to develop a high efficiency advanced coal combustor (HEACC) for coal-based fuels capable of being retrofitted to industrial boilers originally designed for firing natural gas, distillate, and/or residual oil. The HEACC system is to be capable of firing microfine coal water fuel (MCWF), MCWF with alkali sorbent (for SO{sub 2} reduction), and dry microfine coal. Design priorities for the system are that it be simple to operate and will offer significant reductions in NO{sub x}, SO{sub x}, and particulate emissions as compared with current coal fired combustor technology. The specific objective of this report is to document the work carried out under Task 1.0 of this contract, ``Cold Flow Burner Development``. As are detailed in the report, key elements of this work included primary air swirler development, burner register geometry design, cold flow burner model testing, and development of burner scale up criteria.

  19. An Integrated Visualization and Basic Molecular Modeling Laboratory for First-Year Undergraduate Medicinal Chemistry

    Science.gov (United States)

    Hayes, Joseph M.

    2014-01-01

    A 3D model visualization and basic molecular modeling laboratory suitable for first-year undergraduates studying introductory medicinal chemistry is presented. The 2 h practical is embedded within a series of lectures on drug design, target-drug interactions, enzymes, receptors, nucleic acids, and basic pharmacokinetics. Serving as a teaching aid…

  20. Fuel Flexible Gas Turbine Combustor Flametube Facility Upgraded

    Science.gov (United States)

    Little, James E.; Nemets, Steve A.; Tornabene, Robert T.; Smith, Timothy D.; Frankenfeld, Bruce J.

    2004-01-01

    In fiscal year 2003, test cell 23 of the Research Combustion Laboratory (RCL 23) at the NASA Glenn Research Center was upgraded with the addition of gaseous hydrogen as a working propellant and the addition of a 450-psig air-supply system. Test flexibility was further enhanced by upgrades to the facility control systems. RCL 23 can now test with gaseous hydrogen flow rates up to 0.05 lbm/sec and jet fuel flow rates up to 0.62 lbm/sec. Research airflow rates up to 3 lbm/sec are possible with the 450-psig supply system over a range of inlet temperatures. Nonvitiated, heated air is supplied from a shell and tube heat exchanger. The maximum nonvitiated facility air temperature is 1100 F at 1.5 lbm/sec. Research-section exhaust temperatures are limited to 3200 F because of material and cooling capacity limits. A variety of support systems are available depending on the research hardware configuration. Test section ignition can be provided via either a hydrogen air torch system or an electronic spark system. Emissions measurements are obtained with either pneumatically or electromechanically actuated gas sample probes, and the electromechanical system allows for radial measurements at a user-specified axial location for measurement of emissions profiles. Gas analysis data can be obtained for a variety of species, including carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NO and NOx), oxygen (O2), unburnt hydrocarbons, and unburnt hydrogen. Facility control is accomplished with a programmable logic control system. Facility operations have been upgraded to a system based on graphical user interface control screens. A data system is available for real-time acquisition and monitoring of both measurements in engineering units and performance calculations. The upgrades have made RCL 23 a highly flexible facility for research into low emissions gas turbine combustor concepts, and the flame tube configuration inherently allows for a variety of fuel nozzle

  1. Large-eddy simulation and acoustic analysis of a turbulent flow field in a swirl-stabilized combustor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Chan; Yoo, Kwang Hee; Sung, Hong Gye [Korea Aerospace University, Goyang (Korea, Republic of)

    2011-10-15

    To conduct a comprehensive study on the flow characteristics and acoustic oscillation in a gas turbine combustor, a 3D large-eddy simulation (LES) was implemented. The formulation consists of the Favre-filtered conservation equations of mass, momentum, and energy. The subgrid-scale dynamics are modeled using a compressible flow version of the Smagorinsky model. To investigate the dominant coherent structure, the proper orthogonal decomposition (POD) method was used for post-processing. The combustor of concern is the LM6000, lean-premixed dry low-NOx annular combustor, developed by General Electric Aircraft Engines (GEAE). Four important characteristics of swirl flow are visualized: vortex breakdown, procession and dissipation of vortical structures, recirculation zones, and helical waves immediately downstream of the swirl injector. It is shown that the turbulent motion of swirl flow directly affects acoustic oscillation through the cycle and spectral analysis. The four most dominant acoustic modes are extracted from the flow field by the POD analysis. The transverse modes in the y and z directions are dominant in all four modes, since the pressure fields are significantly affected by swirl flow.

  2. Development of collaborative-creative learning model using virtual laboratory media for instrumental analytical chemistry lectures

    Science.gov (United States)

    Zurweni, Wibawa, Basuki; Erwin, Tuti Nurian

    2017-08-01

    The framework for teaching and learning in the 21st century was prepared with 4Cs criteria. Learning providing opportunity for the development of students' optimal creative skills is by implementing collaborative learning. Learners are challenged to be able to compete, work independently to bring either individual or group excellence and master the learning material. Virtual laboratory is used for the media of Instrumental Analytical Chemistry (Vis, UV-Vis-AAS etc) lectures through simulations computer application and used as a substitution for the laboratory if the equipment and instruments are not available. This research aims to design and develop collaborative-creative learning model using virtual laboratory media for Instrumental Analytical Chemistry lectures, to know the effectiveness of this design model adapting the Dick & Carey's model and Hannafin & Peck's model. The development steps of this model are: needs analyze, design collaborative-creative learning, virtual laboratory media using macromedia flash, formative evaluation and test of learning model effectiveness. While, the development stages of collaborative-creative learning model are: apperception, exploration, collaboration, creation, evaluation, feedback. Development of collaborative-creative learning model using virtual laboratory media can be used to improve the quality learning in the classroom, overcome the limitation of lab instruments for the real instrumental analysis. Formative test results show that the Collaborative-Creative Learning Model developed meets the requirements. The effectiveness test of students' pretest and posttest proves significant at 95% confidence level, t-test higher than t-table. It can be concluded that this learning model is effective to use for Instrumental Analytical Chemistry lectures.

  3. Predicting turnaround time reductions of the diagnostic track in the histopathology laboratory using mathematical modelling.

    Science.gov (United States)

    Leeftink, A G; Boucherie, R J; Hans, E W; Verdaasdonk, M A M; Vliegen, I M H; van Diest, P J

    2016-09-01

    Pathology departments face a growing volume of more and more complex testing in an era where healthcare costs tend to explode and short turnaround times (TATs) are expected. In contrast, the histopathology workforce tends to shrink, so histopathology employees experience high workload during their shifts. This points to the need for efficient planning of activities in the histopathology laboratory, to ensure an equal division of workload and low TATs, at minimum costs. The histopathology laboratory of a large academic hospital in The Netherlands was analysed using mathematical modelling. Data were collected from the Laboratory Management System to determine laboratory TATs and workload performance during regular working hours. A mixed integer linear programme (MILP) was developed to model the histopathology processes and to measure the expected performance of possible interventions in terms of TATs and spread of workload. The MILP model predicted that tissue processing at specific moments during the day, combined with earlier starting shifts, can result in up to 25% decrease of TATs, and a more equally spread workload over the day. Mathematical modelling can help to optimally organise the workload in the histopathology laboratory by predicting the performance of possible interventions before actual implementation. The interventions that were predicted by the model to have the highest performance have been implemented in the histopathology laboratory of University Medical Center Utrecht. Further research should be executed to collect empirical evidence and evaluate the actual impact on TAT, quality of work and employee stress levels. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  4. Computational Analysis of Dynamic SPK(S8)-JP8 Fueled Combustor-Sector Performance

    Science.gov (United States)

    Ryder, R.; Hendricks, Roberts C.; Huber, M. L.; Shouse, D. T.

    2010-01-01

    Civil and military flight tests using blends of synthetic and biomass fueling with jet fuel up to 50:50 are currently considered as "drop-in" fuels. They are fully compatible with aircraft performance, emissions and fueling systems, yet the design and operations of such fueling systems and combustors must be capable of running fuels from a range of feedstock sources. This paper provides Smart Combustor or Fuel Flexible Combustor designers with computational tools, preliminary performance, emissions and particulates combustor sector data. The baseline fuel is kerosene-JP-8+100 (military) or Jet A (civil). Results for synthetic paraffinic kerosene (SPK) fuel blends show little change with respect to baseline performance, yet do show lower emissions. The evolution of a validated combustor design procedure is fundamental to the development of dynamic fueling of combustor systems for gas turbine engines that comply with multiple feedstock sources satisfying both new and legacy systems.

  5. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    Science.gov (United States)

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  6. Numerical simulations of single and multi-staged injection of H2 in a supersonic scramjet combustor

    Directory of Open Access Journals (Sweden)

    L. Abu-Farah

    2014-12-01

    Full Text Available Computational fluid dynamics (CFD simulations of a single staged injection of H2 through a central wedge shaped strut and a multi-staged injection through wall injectors are carried out by using Ansys CFX-12 code. Unstructured tetrahedral grids for narrow channel and quarter geometries of the combustor are generated by using ICEM CFD. Steady three-dimensional (3D Reynolds-averaged Navier-stokes (RANS simulations are carried out in the case of no H2 injection and compared with the simulations of single staged pilot and/or main H2 injections and multistage injection. Shear stress transport (SST based on k-ω turbulent model is adopted. Flow field visualization (complex shock waves interactions and static pressure distribution along the wall of the combustor are predicted and compared with the experimental schlieren images and measured wall static pressures for validation. A good agreement is found between the CFD predicted results and the measured data. The narrow and quarter geometries of the combustor give similar results with very small differences. Multi-staged injections of H2 enhance the turbulent H2/air mixing by forming vortices and additional shock waves (bow shocks.

  7. Thermionic combustor application to combined gas and steam turbine power plants

    Science.gov (United States)

    Miskolczy, G.; Wang, C. C.; Lieb, D. P.; Margulies, A. E.; Fusegni, L. J.; Lovell, B. J.

    A design for the insertion of thermionic converters into the wall of a conventional combustor to produce electricity in a topping cycle is described, and a study for applications in gas and steam generators of 70 and 30 MW is evaluated for engineering and economic feasibility. Waste heat from the thermionic elements is used to preheat the combustor air; the heat absorbed by the elements plus further quenching of the exhaust gases with ammonia is projected to reduce NO(x) emissions to acceptable levels. Schematics, flow diagrams, and components of a computer model for cost projections are provided. It was found that temperatures around the emitters must be maintained above 1,600 K, with maximum efficiency and allowable temperature at 1,800 K, while collectors generate maximally at 950 K, with a corresponding work function of 1.5 eV. Cost sensitive studies indicate an installed price of $475/kW for the topping cycle, with improvements in thermionic converter characteristics bringing the cost to $375/kW at a busbar figure of 500 mills/kWh.

  8. Development of an advanced high efficiency coal combustor for boiler retrofit

    Energy Technology Data Exchange (ETDEWEB)

    LaFlesh, R.C.; Rini, M.J.; McGowan, J.G.

    1989-10-01

    The overall objective of this program is to develop a high efficiency advanced coal combustor (HEACC) for coal-based fuels capable of being retrofitted to industrial boilers originally designed for firing natural gas, distillate, and/or residual oil. The HEACC system is to be capable of firing microfine coal water fuel (MCWF), MCWF with alkali sorbent (for SO{sub 2} reduction), and dry microfine coal. Design priorities for the system are that it be simple to operate and will offer significant reductions in NO{sub x}, SO{sub x}, and particulate emissions as compared with current coal fired combustor technology. The specific objective of this report is to document the work carried out under Task 1.0 of this contract, Cold Flow Burner Development''. As are detailed in the report, key elements of this work included primary air swirler development, burner register geometry design, cold flow burner model testing, and development of burner scale up criteria.

  9. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  10. Low NOx heavy fuel combustor concept program addendum: Low/mid heating value gaseous fuel evaluation

    Science.gov (United States)

    Novick, A. S.; Troth, D. L.

    1982-01-01

    The combustion performance of a rich/quench/lean (RQL) combustor was evaluated when operated on low and mid heating value gaseous fuels. Two synthesized fuels were prepared having lower heating values of 10.2 MJ/cu m. (274 Btu/scf) and 6.6 MJ/cu m (176 Btu/scf). These fuels were configured to be representative of actual fuels, being composed primarily of nitrogen, hydrogen, carbon monoxide, and carbon dioxide. A liquid fuel air assist fuel nozzle was modified to inject both of the gaseous fuels. The RQL combustor liner was not changed from the configuration used when the liquid fuels were tested. Both gaseous fuels were tested over a range of power levels from 50 percent load to maximum rated power of the DDN Model 570-K industrial gas turbine engine. Exhaust emissions were recorded for four power level at several rich zone equivalence ratios to determine NOx sensitivity to the rich zone operating point. For the mid Btu heating value gas, ammonia was added to the fuel to simulate a fuel bound nitrogen type gaseous fuel. Results at the testing showed that for the low heating value fuel NOx emissions were all below 20 ppmc and smoke was below a 10 smoke number. For the mid heating value fuel, NOx emissions were in the 50 to 70 ppmc range with the smoke below a 10 smoke number.

  11. Modelling of the physical behaviour of water saturated clay barriers. Laboratory tests, material models and finite element application

    International Nuclear Information System (INIS)

    Boergesson, L.; Johannesson, L.E.; Sanden, T.; Hernelind, J.

    1995-09-01

    This report deals with laboratory testing and modelling of the thermo-hydro-mechanical (THM) properties of water saturated bentonite based buffer materials. A number of different laboratory tests have been performed and the results are accounted for. These test results have lead to a tentative material model, consisting of several sub-models, which is described in the report. The tentative model has partly been adapted to the material models available in the finite element code ABAQUS and partly been implemented and incorporated in the code. The model that can be used for ABAQUS calculations agrees with the tentative model with a few exceptions. The model has been used in a number of verification calculations, simulating different laboratory tests, and the results have been compared with actual measurements. These calculations show that the model generally can be used for THM calculations of the behaviour of water saturated buffer materials, but also that there is still a lack of some understanding. It is concluded that the available model is relevant for the required predictions of the THM behaviour but that a further improvement of the model is desirable

  12. Pulse Combustor CRADA PC91-001 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    none

    1992-08-31

    As outlined in the Cooperative Research and Development Agreement (CRADA) between BO Technical Developments, Ltd. (BO Tech) and the Pittsburgh Energy Technology Center (PETC) Coal Combustion Division, a BO Tech designed pulse-blade combustor was studied at PETC. Phase 1 involved limited tests of a single-blade pulsed-combustor module to evaluate the suitability of a gas-designed unit for firing coal for use in residential, commercial, or industrial sectors. During the course of the project, three different pulsed blade burners were designed and fabricated by BO Tech and subsequently delivered to PETC for evaluation. These units were designed to allow modification of the furnace dimensions, which would give PETC a means to take simple steps to improve coal firing performance is required. No major furnace design changes were to be included as part of the phase 1 activities.

  13. Coal-Fired MHD Combustor Development Project, Phase 3D

    Science.gov (United States)

    1985-02-01

    The Coal-Fired MHD Combustor Development Project (phase 3D) is reported. The scope encompasses development work on the 50 MW/sub t/ combustor related to test support at the CDIF, fabrication and assembly of first and second stage hardware, plans for second stage design verification testing and power testing, and designs for a continuous slag rejector and low preheat inlet section. Progress includes the following: (1) operational verification testing of the first stage at the CDIF was completed; (2) assembly and checkout of the second first stage, two second stages, and PEM is 75 to 90% completed; (3) conceptual designs for a continuous slag rejector and low preheat inlet section are completed and low preheat preliminary design work is 75% completed; and (4) revision of the users' manual to include the second stage is 75% completed and a draft Test Plan for power train testing is reviewed.

  14. Systems and methods for preventing flashback in a combustor assembly

    Science.gov (United States)

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Stevenson, Christian Xavier

    2016-04-05

    Embodiments of the present application include a combustor assembly. The combustor assembly may include a combustion chamber, a first plenum, a second plenum, and one or more elongate air/fuel premixing injection tubes. Each of the elongate air/fuel premixing injection tubes may include a first length at least partially disposed within the first plenum and configured to receive a first fluid from the first plenum. Moreover, each of the elongate air/fuel premixing injection tubes may include a second length disposed downstream of the first length and at least partially disposed within the second plenum. The second length may be formed of a porous wall configured to allow a second fluid from the second plenum to enter the second length and create a boundary layer about the porous wall.

  15. System for supporting bundled tube segments within a combustor

    Energy Technology Data Exchange (ETDEWEB)

    Melton, Patrick Benedict

    2016-03-01

    A system for supporting bundled tube segments within a combustor includes an annular sleeve that extends circumferentially and axially within the combustor, a support lug that extends radially inward from the annular sleeve and an annular support frame that is disposed within the annular sleeve. The annular support frame includes an inner ring portion, an outer ring portion and a plurality of spokes that extend radially between the inner and outer ring portions. The inner ring portion, the outer ring portion and the plurality of spokes define an annular array of openings for receiving a respective bundled tube segment. The inner ring portion is connected to each bundled tube segment and the outer ring portion is coupled to the support lug.

  16. Analytical fuel property effects, small combustors, phase 1

    Science.gov (United States)

    Cohen, J. D.

    1983-01-01

    The effects of nonstandard aviation fuels on a typical small gas turbine combustor was analyzed. The T700/CT7 engine family was chosen as being representative of the class of aircraft power plants desired. Fuel properties, as specified by NASA, are characterized by low hydrogen content and high aromatics levels. Higher than normal smoke output and flame radiation intensity for the current T700 combustor which serves as a baseline were anticipated. It is, therefore, predicted that out of specification smoke visibility and higher than normal shell temperatures will exist when using NASA ERBS fuels with a consequence of severe reduction in cyclic life. Three new designs are proposed to compensate for the deficiencies expected with the existing design. They have emerged as the best of the eight originally proposed redesigns or combinations thereof. After the five choices that were originally made by NASA on the basis of competing performance factors, General Electric narrowed the field to the three proposed.

  17. Combustion and direct energy conversion inside a micro-combustor

    International Nuclear Information System (INIS)

    Lei, Yafeng; Chen, Wei; Lei, Jiang

    2016-01-01

    Highlights: • The flammability range of micro-combustor was broadened with heat recirculation. • The quenching diameter decreased with heat recirculation compared to without recirculation. • The surface areas to volume ratio was the most important parameter affecting the energy conversion efficiency. • The maximum conversion efficiency (3.15%) was achieved with 1 mm inner diameter. - Abstract: Electrical energy can be generated by employing a micro-thermophotovoltaic (TPV) cell which absorbs thermal radiation from combustion taking place in a micro-combustor. The stability of combustion in a micro-combustor is essential for operating a micro-power system using hydrogen and hydrocarbon fuels as energy source. To understand the mechanism of sustaining combustion within the quenching distance of fuel, this study proposed an annular micro combustion tube with recirculation of exhaust heat. To explore the feasibility of combustion in the micro annular tube, the parameters influencing the combustion namely, quenching diameter, and flammability were studied through numerical simulation. The results indicated that combustion could be realized in micro- combustor using heat recirculation. Following results were obtained from simulation. The quenching diameter reduced from 1.3 mm to 0.9 mm for heat recirculation at equivalence ratio of 1; the lean flammability was 2.5%–5% lower than that of without heat recirculation for quenching diameters between 2 mm and 5 mm. The overall energy conversion efficiency varied at different inner diameters. A maximum efficiency of 3.15% was achieved at an inner diameter of 1 mm. The studies indicated that heat recirculation is an effective strategy to maintain combustion and to improve combustion limits in micro-scale system.

  18. Nonintrusive transceiver and method for characterizing temperature and velocity fields in a gas turbine combustor

    Energy Technology Data Exchange (ETDEWEB)

    DeSilva, Upul P.; Claussen, Heiko

    2017-09-05

    An acoustic transceiver is implemented for measuring acoustic properties of a gas in a turbine engine combustor. The transceiver housing defines a measurement chamber and has an opening adapted for attachment to a turbine engine combustor wall. The opening permits propagation of acoustic signals between the gas in the turbine engine combustor and gas in the measurement chamber. An acoustic sensor mounted to the housing receives acoustic signals propagating in the measurement chamber, and an acoustic transmitter mounted to the housing creates acoustic signals within the measurement chamber. An acoustic measurement system includes at least two such transceivers attached to a turbine engine combustor wall and connected to a controller.

  19. Design and Study of a Low-Cost Laboratory Model Digital Wind Power Meter

    Science.gov (United States)

    Radhakrishnan, Rugmini; Karthika, S.

    2010-01-01

    A vane-type low-cost laboratory model anemometer cum power meter is designed and constructed for measuring low wind energy created from accelerating fluids. The constructed anemometer is a device which records the electrical power obtained by the conversion of wind power using a wind sensor coupled to a DC motor. It is designed for its…

  20. Examination of Bond Properties through Infrared Spectroscopy and Molecular Modeling in the General Chemistry Laboratory

    Science.gov (United States)

    Csizmar, Clifford M.; Force, Dee Ann; Warner, Don L.

    2012-01-01

    A concerted effort has been made to increase the opportunities for undergraduate students to address scientific problems employing the processes used by practicing chemists. As part of this effort, an infrared (IR) spectroscopy and molecular modeling experiment was developed for the first-year general chemistry laboratory course. In the…

  1. A Laboratory Exercise Using a Physical Model for Demonstrating Countercurrent Heat Exchange

    Science.gov (United States)

    Loudon, Catherine; Davis-Berg, Elizabeth C.; Botz, Jason T.

    2012-01-01

    A physical model was used in a laboratory exercise to teach students about countercurrent exchange mechanisms. Countercurrent exchange is the transport of heat or chemicals between fluids moving in opposite directions separated by a permeable barrier (such as blood within adjacent blood vessels flowing in opposite directions). Greater exchange of…

  2. Development of Laboratory Model Ecosystems as Early Warning Elements of Environmental Pollution

    Science.gov (United States)

    1974-12-01

    AD-AOll 851 DEVELOPMENT OF LABORATORY MODEL ECOSYSTEMS AS EARLY WARNING ELEMENTS OF ENVIRONMENTAL POLLUTION Robert L. Metcalf... ENVIRONMENTAL POLLUTION Robert L. Metcalf, Ph. D. University of Illinois Urbana-Champaign, Illinois INTRODUCTION Problems of environmental pollution with...house dust is unsafe to breathe (Ewing and Pearson, 1974). Most of the source of our concern about environmental pollution by trace substances relates

  3. Implementation of Argument-Driven Inquiry as an Instructional Model in a General Chemistry Laboratory Course

    Science.gov (United States)

    Kadayifci, Hakki; Yalcin-Celik, Ayse

    2016-01-01

    This study examined the effectiveness of Argument-Driven Inquiry (ADI) as an instructional model in a general chemistry laboratory course. The study was conducted over the course of ten experimental sessions with 125 pre-service science teachers. The participants' level of reflective thinking about the ADI activities, changes in their science…

  4. Laboratory-based grain-shape models for simulating dust infrared spectra

    NARCIS (Netherlands)

    Mutschke, H.; Min, M.; Tamanai, A.

    2009-01-01

    Context. Analysis of thermal dust emission spectra for dust mineralogy and physical grain properties depends on comparison spectra, which are either laboratory-measured infrared extinction spectra or calculated extinction cross sections based on certain grain models. Often, the agreement between

  5. Development of a laboratory model of SSSC using RTAI on Linux ...

    Indian Academy of Sciences (India)

    The controller is tested on a small scale laboratory model of a Voltage Source Con- verter (VSC) connected in series with a .... computer used in health care and military applications. There are several ... 3.3a Communication with linux processes: RTAI supports two mechanisms to provide com- munication between kernel ...

  6. 3D Printing of Protein Models in an Undergraduate Laboratory: Leucine Zippers

    Science.gov (United States)

    Meyer, Scott C.

    2015-01-01

    An upper-division undergraduate laboratory experiment is described that explores the structure/function relationship of protein domains, namely leucine zippers, through a molecular graphics computer program and physical models fabricated by 3D printing. By generating solvent accessible surfaces and color-coding hydrophobic, basic, and acidic amino…

  7. Model-based fuzzy control solutions for a laboratory Antilock Braking System

    DEFF Research Database (Denmark)

    Precup, Radu-Emil; Spataru, Sergiu; Rǎdac, Mircea-Bogdan

    2010-01-01

    This paper gives two original model-based fuzzy control solutions dedicated to the longitudinal slip control of Antilock Braking System laboratory equipment. The parallel distributed compensation leads to linear matrix inequalities which guarantee the global stability of the fuzzy control systems....... Real-time experimental results validate the new fuzzy control solutions....

  8. Constraints on the rheology of the partially molten mantle from numerical models of laboratory experiments

    Science.gov (United States)

    Rudge, J. F.; Alisic Jewell, L.; Rhebergen, S.; Katz, R. F.; Wells, G. N.

    2015-12-01

    One of the fundamental components in any dynamical model of melt transport is the rheology of partially molten rock. This rheology is poorly understood, and one way in which a better understanding can be obtained is by comparing the results of laboratory deformation experiments to numerical models. Here we present a comparison between numerical models and the laboratory setup of Qi et al. 2013 (EPSL), where a cylinder of partially molten rock containing rigid spherical inclusions was placed under torsion. We have replicated this setup in a finite element model which solves the partial differential equations describing the mechanical process of compaction. These computationally-demanding 3D simulations are only possible due to the recent development of a new preconditioning method for the equations of magma dynamics. The experiments show a distinct pattern of melt-rich and melt-depleted regions around the inclusions. In our numerical models, the pattern of melt varies with key rheological parameters, such as the ratio of bulk to shear viscosity, and the porosity- and strain-rate-dependence of the shear viscosity. These observed melt patterns therefore have the potential to constrain rheological properties. While there are many similarities between the experiments and the numerical models, there are also important differences, which highlight the need for better models of the physics of two-phase mantle/magma dynamics. In particular, the laboratory experiments display more pervasive melt-rich bands than is seen in our numerics.

  9. Flame dynamics of a meso-scale heat recirculating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Vijayan, V.; Gupta, A.K. [Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States)

    2010-12-15

    The dynamics of premixed propane-air flame in a meso-scale ceramic combustor has been examined here. The flame characteristics in the combustor were examined by measuring the acoustic emissions and preheat temperatures together with high-speed cinematography. For the small-scale combustor, the volume to surface area ratio is small and hence the walls have significant effect on the global flame structure, flame location and flame dynamics. In addition to the flame-wall thermal coupling there is a coupling between flame and acoustics in the case of confined flames. Flame-wall thermal interactions lead to low frequency flame fluctuations ({proportional_to}100 Hz) depending upon the thermal response of the wall. However, the flame-acoustic interactions can result in a wide range of flame fluctuations ranging from few hundred Hz to few kHz. Wall temperature distribution is one of the factors that control the amount of reactant preheating which in turn effects the location of flame stabilization. Acoustic emission signals and high-speed flame imaging confirmed that for the present case flame-acoustic interactions have more significant effect on flame dynamics. Based on the acoustic emissions, five different flame regimes have been identified; whistling/harmonic mode, rich instability mode, lean instability mode, silent mode and pulsating flame mode. (author)

  10. Recurrence networks to study dynamical transitions in a turbulent combustor

    Science.gov (United States)

    Godavarthi, V.; Unni, V. R.; Gopalakrishnan, E. A.; Sujith, R. I.

    2017-06-01

    Thermoacoustic instability and lean blowout are the major challenges faced when a gas turbine combustor is operated under fuel lean conditions. The dynamics of thermoacoustic system is the result of complex nonlinear interactions between the subsystems—turbulent reactive flow and the acoustic field of the combustor. In order to study the transitions between the dynamical regimes in such a complex system, the time series corresponding to one of the dynamic variables is transformed to an ɛ-recurrence network. The topology of the recurrence network resembles the structure of the attractor representing the dynamics of the system. The transitions in the thermoacoustic system are then captured as the variation in the topological characteristics of the network. We show the presence of power law degree distribution in the recurrence networks constructed from time series acquired during the occurrence of combustion noise and during the low amplitude aperiodic oscillations prior to lean blowout. We also show the absence of power law degree distribution in the recurrence networks constructed from time series acquired during the occurrence of thermoacoustic instability and during the occurrence of intermittency. We demonstrate that the measures derived from recurrence network can be used as tools to capture the transitions in the turbulent combustor and also as early warning measures for predicting impending thermoacoustic instability and blowout.

  11. Source Release Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area

    International Nuclear Information System (INIS)

    Becker, B.H.

    2002-01-01

    A source release model was developed to determine the release of contaminants into the shallow subsurface, as part of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) evaluation at the Idaho National Engineering and Environmental Laboratory's (INEEL) Subsurface Disposal Area (SDA). The output of the source release model is used as input to the subsurface transport and biotic uptake models. The model allowed separating the waste into areas that match the actual disposal units. This allows quantitative evaluation of the relative contribution to the total risk and allows evaluation of selective remediation of the disposal units within the SDA

  12. Dynamic data-driven prediction of instability in a swirl-stabilized combustor

    Directory of Open Access Journals (Sweden)

    Soumalya Sarkar

    2016-12-01

    Full Text Available Combustion instability poses a negative impact on the performance and structural durability of both land-based and aircraft gas turbine engines, and early detection of combustion instabilities is of paramount importance not only for performance monitoring and fault diagnosis, but also for initiating efficient decision and control of such engines. Combustion instability is, in general, characterized by self-sustained growth of large-amplitude pressure tones that are caused by a positive feedback arising from complex coupling of localized hydrodynamic perturbations, heat energy release, and acoustics of the combustor. This paper proposes a fast dynamic data-driven method for detecting early onsets of thermo-acoustic instabilities, where the underlying algorithms are built upon the concepts of symbolic time series analysis (STSA via generalization of D-Markov machine construction. The proposed method captures the spatiotemporal co-dependence among time series from heterogeneous sensors (e.g. pressure and chemiluminescence to generate an information-theoretic precursor, which is uniformly applicable across multiple operating regimes of the combustion process. The proposed method is experimentally validated on the time-series data, generated from a laboratory-scale swirl-stabilized combustor, while inducing thermo-acoustic instabilities for various protocols (e.g. increasing Reynolds number (Re at a constant fuel flow rate and reducing equivalence ratio at a constant air flow rate at varying air-fuel premixing levels. The underlying algorithms are developed based on D-Markov entropy rates, and the resulting instability precursor measure is rigorously compared with the state-of-the-art techniques in terms of its performance of instability prediction, computational complexity, and robustness to sensor noise.

  13. Modeling Soil Organic Carbon at Regional Scale by Combining Multi-Spectral Images with Laboratory Spectra.

    Directory of Open Access Journals (Sweden)

    Yi Peng

    Full Text Available There is a great challenge in combining soil proximal spectra and remote sensing spectra to improve the accuracy of soil organic carbon (SOC models. This is primarily because mixing of spectral data from different sources and technologies to improve soil models is still in its infancy. The first objective of this study was to integrate information of SOC derived from visible near-infrared reflectance (Vis-NIR spectra in the laboratory with remote sensing (RS images to improve predictions of topsoil SOC in the Skjern river catchment, Denmark. The second objective was to improve SOC prediction results by separately modeling uplands and wetlands. A total of 328 topsoil samples were collected and analyzed for SOC. Satellite Pour l'Observation de la Terre (SPOT5, Landsat Data Continuity Mission (Landsat 8 images, laboratory Vis-NIR and other ancillary environmental data including terrain parameters and soil maps were compiled to predict topsoil SOC using Cubist regression and Bayesian kriging. The results showed that the model developed from RS data, ancillary environmental data and laboratory spectral data yielded a lower root mean square error (RMSE (2.8% and higher R2 (0.59 than the model developed from only RS data and ancillary environmental data (RMSE: 3.6%, R2: 0.46. Plant-available water (PAW was the most important predictor for all the models because of its close relationship with soil organic matter content. Moreover, vegetation indices, such as the Normalized Difference Vegetation Index (NDVI and Enhanced Vegetation Index (EVI, were very important predictors in SOC spatial models. Furthermore, the 'upland model' was able to more accurately predict SOC compared with the 'upland & wetland model'. However, the separately calibrated 'upland and wetland model' did not improve the prediction accuracy for wetland sites, since it was not possible to adequately discriminate the vegetation in the RS summer images. We conclude that laboratory Vis

  14. Effect of the air-fuel mixing on the NOx yield in a low-emission gas-turbine plant combustor

    Science.gov (United States)

    Vasil'ev, V. D.; Bulysova, L. A.; Berne, A. L.

    2016-04-01

    The article deals with construction of a simplified model of inhibition of nitric oxides formed in the combustors of the gas-turbine plants (GTPs) operating on natural gas. A combustor in which premixed, lean air-fuel mixtures are burnt is studied theoretically and experimentally. The research was carried out using a full-scale combustor that had parameters characteristic of modern GTPs. The article presents the results computed by the FlowVision software and the results of the experiments carried out on the test bench of the All-Russia Thermal Engineering Institute. The calculations and the tests were conducted under the following conditions: a flow rate of approximately 4.6 kg/s, a pressure to 450 kPa, an air temperature at the combustor inlet of approximately 400°C, the outlet temperature t 3 ≤ 1200°C, and natural gas as the fuel. The comparison of the simulated parameters with the experimental results underlies the constructed correlation dependence of the experimental NO x emission on the calculated parameter of nonuniform fuel concentration at the premixing zone outlet. The postulate about a weak dependence of the emission of NO x formed upon combustion of a perfectly mixed air-fuel mixture—when the methane concentration in air is constant at any point of the air-fuel mixture, i.e., constant in the mixture bulk—on the pressure in the combustor has been experimentally proven. The correctness and the practicability of the stationary mathematical model of the mixing process used to assess the NO x emission by the calculated amount of the air-fuel mixture generated in the premixing zone has been validated. This eliminates some difficulties that arise in the course of calculation of combustion and formation of NO x .

  15. Using Performance Assessment Model in Physics Laboratory to Increase Students’ Critical Thinking Disposition

    Science.gov (United States)

    Emiliannur, E.; Hamidah, I.; Zainul, A.; Wulan, A. R.

    2017-09-01

    Performance Assessment Model (PAM) has been developed to represent the physics concepts which able to be devided into five experiments: 1) acceleration due to gravity; 2) Hooke’s law; 3) simple harmonic motion; 4) work-energy concepts; and 5) the law of momentum conservation. The aim of this study was to determine the contribution of PAM in physics laboratory to increase students’ Critical Thinking Disposition (CTD) at senior high school. Subject of the study were 11th grade consist 32 students of a senior high school in Lubuk Sikaping, West Sumatera. The research used one group pretest-postest design. Data was collected through essay test and questionnaire about CTD. Data was analyzed using quantitative way with N-gain value. This study concluded that performance assessmet model effectively increases the N-gain at medium category. It means students’ critical thinking disposition significant increase after implementation of performance assessment model in physics laboratory.

  16. Coherent anti-Stokes Raman scattering for quantitative temperature and concentration measurements in a high-pressure gas turbine combustor rig

    Science.gov (United States)

    Thariyan, Mathew Paul

    conditions. The insight into the reacting flow structure provided by these measurements is discussed. Such measurements at conditions similar to those of aircraft gas turbine combustors are extremely useful for testing combustion models being used to predict performance of these systems.

  17. Pacific Northwest Laboratory (PNL) spent fuel transportation and handling facility models

    International Nuclear Information System (INIS)

    Andrews, W.B.; Bower, J.C.; Burnett, R.A.; Engel, R.L.; Rolland, C.W.

    1979-09-01

    A spent fuel logistics study was conducted in support of the US DOE program to develop facilities for preparing spent unreprocessed fuel from commercial LWRs for geological storage. Two computerized logistics models were developed. The first one was the site evaluation model. Two studies of spent fuel handling facility and spent fuel disposal facility siting were completed; the first postulates a single spent fuel handling facility located at any of six DOE laboratory sites, while the second study examined siting strategies with the spent fuel repository relative to the spent fuel handling facility. A second model to conduct storage/handling facility simulations was developed

  18. Ultrasound data for laboratory calibration of an analytical model to calculate crack depth on asphalt pavements.

    Science.gov (United States)

    Franesqui, Miguel A; Yepes, Jorge; García-González, Cándida

    2017-08-01

    This article outlines the ultrasound data employed to calibrate in the laboratory an analytical model that permits the calculation of the depth of partial-depth surface-initiated cracks on bituminous pavements using this non-destructive technique. This initial calibration is required so that the model provides sufficient precision during practical application. The ultrasonic pulse transit times were measured on beam samples of different asphalt mixtures (semi-dense asphalt concrete AC-S; asphalt concrete for very thin layers BBTM; and porous asphalt PA). The cracks on the laboratory samples were simulated by means of notches of variable depths. With the data of ultrasound transmission time ratios, curve-fittings were carried out on the analytical model, thus determining the regression parameters and their statistical dispersion. The calibrated models obtained from laboratory datasets were subsequently applied to auscultate the evolution of the crack depth after microwaves exposure in the research article entitled "Top-down cracking self-healing of asphalt pavements with steel filler from industrial waste applying microwaves" (Franesqui et al., 2017) [1].

  19. Ultrasound data for laboratory calibration of an analytical model to calculate crack depth on asphalt pavements

    Directory of Open Access Journals (Sweden)

    Miguel A. Franesqui

    2017-08-01

    Full Text Available This article outlines the ultrasound data employed to calibrate in the laboratory an analytical model that permits the calculation of the depth of partial-depth surface-initiated cracks on bituminous pavements using this non-destructive technique. This initial calibration is required so that the model provides sufficient precision during practical application. The ultrasonic pulse transit times were measured on beam samples of different asphalt mixtures (semi-dense asphalt concrete AC-S; asphalt concrete for very thin layers BBTM; and porous asphalt PA. The cracks on the laboratory samples were simulated by means of notches of variable depths. With the data of ultrasound transmission time ratios, curve-fittings were carried out on the analytical model, thus determining the regression parameters and their statistical dispersion. The calibrated models obtained from laboratory datasets were subsequently applied to auscultate the evolution of the crack depth after microwaves exposure in the research article entitled “Top-down cracking self-healing of asphalt pavements with steel filler from industrial waste applying microwaves” (Franesqui et al., 2017 [1].

  20. The preliminary design of an annular combustor for a mini gas turbine

    CSIR Research Space (South Africa)

    Meyers, Bronwyn C

    2015-10-01

    Full Text Available This study involves the redesign of the combustor liner for a 200N mini gas turbine engine using first principles and the design methods of the NREC series as shown in Figure 1. The combustor design was performed using five different operating...

  1. Three-dimensional particle image velocimetry in a generic can-type gas turbine combustor

    CSIR Research Space (South Africa)

    Meyers, BC

    2009-09-01

    Full Text Available The three-dimensional flow field inside a generic can-type, forward flow, experimental combustor was measured. A stereoscopic Particle Image Velocimetry (PIV) system was used to obtain the flow field of the combustor in the non-reacting condition...

  2. International on Workshop Advances in Laboratory Testing & Modelling of Soils and Shales

    CERN Document Server

    Laloui, Lyesse

    2017-01-01

    In this spirit, the ATMSS International Workshop “Advances in Laboratory Testing & Modelling of Soils and Shales” (Villars-sur-Ollon, Switzerland; 18-20 January 2017) has been organized to promote the exchange of ideas, experience and state of the art among major experts active in the field of experimental testing and modelling of soils and shales. The Workshop has been organized under the auspices of the Technical Committees TC-101 “Laboratory Testing”, TC-106 “Unsaturated Soils” and TC-308 “Energy Geotechnics” of the International Society of Soil Mechanics and Geotechnical Engineering. This volume contains the invited keynote and feature lectures, as well as the papers that have been presented at the Workshop. The topics of the lectures and papers cover a wide range of theoretical and experimental research, including unsaturated behaviour of soils and shales, multiphysical testing of geomaterials, hydro–mechanical behaviour of shales and stiff clays, the geomechanical behaviour of the ...

  3. AstraZeneca and Covance Laboratories Clinical Bioanalysis Alliance: an evolutionary outsourcing model.

    Science.gov (United States)

    Arfvidsson, Cecilia; Severin, Paul; Holmes, Victoria; Mitchell, Richard; Bailey, Christopher; Cape, Stephanie; Li, Yan; Harter, Tammy

    2017-08-01

    The AstraZeneca and Covance Laboratories Clinical Bioanalysis Alliance (CBioA) was launched in 2011 after a period of global economic recession. In this challenging environment, AstraZeneca elected to move to a full and centralized outsourcing model that could optimize the number of people supporting bioanalytical work and reduce the analytical cost. This paper describes the key aspects of CBioA, the innovative operational model implemented, and our ways of ensuring this was much more than simply a cost reduction exercise. As we have recently passed the first 5-year cycle, this paper also summarizes some of the concluding benefits, wins and lessons learned, and how we now plan to extend and develop the relationship even further moving into a new clinical laboratory partnership.

  4. A laboratory-scale comparison of rate of spread model predictions using chaparral fuel beds – preliminary results

    Science.gov (United States)

    D.R. Weise; E. Koo; X. Zhou; S. Mahalingam

    2011-01-01

    Observed fire spread rates from 240 laboratory fires in horizontally-oriented single-species live fuel beds were compared to predictions from various implementations and modifications of the Rothermel rate of spread model and a physical fire spread model developed by Pagni and Koo. Packing ratio of the laboratory fuel beds was generally greater than that observed in...

  5. Accuracy of finite-difference modeling of seismic waves : Simulation versus laboratory measurements

    Science.gov (United States)

    Arntsen, B.

    2017-12-01

    The finite-difference technique for numerical modeling of seismic waves is still important and for some areas extensively used.For exploration purposes is finite-difference simulation at the core of both traditional imaging techniques such as reverse-time migration and more elaborate Full-Waveform Inversion techniques.The accuracy and fidelity of finite-difference simulation of seismic waves are hard to quantify and meaningfully error analysis is really onlyeasily available for simplistic media. A possible alternative to theoretical error analysis is provided by comparing finite-difference simulated data with laboratory data created using a scale model. The advantage of this approach is the accurate knowledge of the model, within measurement precision, and the location of sources and receivers.We use a model made of PVC immersed in water and containing horizontal and tilted interfaces together with several spherical objects to generateultrasonic pressure reflection measurements. The physical dimensions of the model is of the order of a meter, which after scaling represents a model with dimensions of the order of 10 kilometer and frequencies in the range of one to thirty hertz.We find that for plane horizontal interfaces the laboratory data can be reproduced by the finite-difference scheme with relatively small error, but for steeply tilted interfaces the error increases. For spherical interfaces the discrepancy between laboratory data and simulated data is sometimes much more severe, to the extent that it is not possible to simulate reflections from parts of highly curved bodies. The results are important in view of the fact that finite-difference modeling is often at the core of imaging and inversion algorithms tackling complicatedgeological areas with highly curved interfaces.

  6. Clinical pharmacology quality assurance program: models for longitudinal analysis of antiretroviral proficiency testing for international laboratories.

    Science.gov (United States)

    DiFrancesco, Robin; Rosenkranz, Susan L; Taylor, Charlene R; Pande, Poonam G; Siminski, Suzanne M; Jenny, Richard W; Morse, Gene D

    2013-10-01

    Among National Institutes of Health HIV Research Networks conducting multicenter trials, samples from protocols that span several years are analyzed at multiple clinical pharmacology laboratories (CPLs) for multiple antiretrovirals. Drug assay data are, in turn, entered into study-specific data sets that are used for pharmacokinetic analyses, merged to conduct cross-protocol pharmacokinetic analysis, and integrated with pharmacogenomics research to investigate pharmacokinetic-pharmacogenetic associations. The CPLs participate in a semiannual proficiency testing (PT) program implemented by the Clinical Pharmacology Quality Assurance program. Using results from multiple PT rounds, longitudinal analyses of recovery are reflective of accuracy and precision within/across laboratories. The objectives of this longitudinal analysis of PT across multiple CPLs were to develop and test statistical models that longitudinally: (1) assess the precision and accuracy of concentrations reported by individual CPLs and (2) determine factors associated with round-specific and long-term assay accuracy, precision, and bias using a new regression model. A measure of absolute recovery is explored as a simultaneous measure of accuracy and precision. Overall, the analysis outcomes assured 97% accuracy (±20% of the final target concentration of all (21) drug concentration results reported for clinical trial samples by multiple CPLs). Using the Clinical Laboratory Improvement Act acceptance of meeting criteria for ≥2/3 consecutive rounds, all 10 laboratories that participated in 3 or more rounds per analyte maintained Clinical Laboratory Improvement Act proficiency. Significant associations were present between magnitude of error and CPL (Kruskal-Wallis P < 0.001) and antiretroviral (Kruskal-Wallis P < 0.001).

  7. Parametric Study of Pulse-Combustor-Driven Ejectors at High-Pressure

    Science.gov (United States)

    Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

    2015-01-01

    Pulse-combustor configurations developed in recent studies have demonstrated performance levels at high-pressure operating conditions comparable to those observed at atmospheric conditions. However, problems related to the way fuel was being distributed within the pulse combustor were still limiting performance. In the first part of this study, new configurations are investigated computationally aimed at improving the fuel distribution and performance of the pulse-combustor. Subsequent sections investigate the performance of various pulse-combustor driven ejector configurations operating at highpressure conditions, focusing on the effects of fuel equivalence ratio and ejector throat area. The goal is to design pulse-combustor-ejector configurations that maximize pressure gain while achieving a thermal environment acceptable to a turbine, and at the same time maintain acceptable levels of NOx emissions and flow non-uniformities. The computations presented here have demonstrated pressure gains of up to 2.8%.

  8. The pollution reduction technology program for can-annular combustor engines - Description and results

    Science.gov (United States)

    Roberts, R.; Fiorentino, A. J.; Diehl, L.

    1976-01-01

    Pollutant reduction and performance characteristics were determined for three successively more advanced combustor concepts. Program Element I consisted of minor modifications to the current production JT8D combustor and fuel system to evaluate means of improved fuel preparation and changes to the basic airflow distribution. Element II addressed versions of the two-staged Vorbix (vortex burning and mixing) combustor and represented a moderate increase in hardware complexity and difficulty of development. The concept selected for Element III employed vaporized fuel as a means of achieving minimum emission levels and represented the greatest difficulty of development and adaptation to the JT8D engine. Test results indicate that the Element I single-stage combustors were capable of dramatic improvement in idle pollutants. The multistage combustors evaluated in Program Elements II and III simultaneously reduced CO, THC and NOx emissions, but were unable to satisfy the current 1979 EPA standards.

  9. Development and testing of pulsed and rotating detonation combustors

    Science.gov (United States)

    St. George, Andrew C.

    Detonation is a self-sustaining, supersonic, shock-driven, exothermic reaction. Detonation combustion can theoretically provide significant improvements in thermodynamic efficiency over constant pressure combustion when incorporated into existing cycles. To harness this potential performance benefit, countless studies have worked to develop detonation combustors and integrate these devices into existing systems. This dissertation consists of a series of investigations on two types of detonation combustors: the pulse detonation combustor (PDC) and the rotating detonation combustor (RDC). In the first two investigations, an array of air-breathing PDCs is integrated with an axial power turbine. The system is initially operated with steady and pulsed cold air flow to determine the effect of pulsed flow on turbine performance. Various averaging approaches are employed to calculate turbine efficiency, but only flow-weighted (e.g., mass or work averaging) definitions have physical significance. Pulsed flow turbine efficiency is comparable to steady flow efficiency at high corrected flow rates and low rotor speeds. At these conditions, the pulse duty cycle expands and the variation of the rotor incidence angle is constrained to a favorable range. The system is operated with pulsed detonating flow to determine the effect of frequency, fill fraction, and rotor speed on turbine performance. For some conditions, output power exceeds the maximum attainable value from steady constant pressure combustion due to a significant increase in available power from the detonation products. However, the turbine component efficiency estimated from classical thermodynamic analysis is four times lower than the steady design point efficiency. Analysis of blade angles shows a significant penalty due to the detonation, fill, and purge processes simultaneously imposed on the rotor. The latter six investigations focus on fundamental research of the RDC concept. A specially-tailored RDC data

  10. Pulsed atmospheric fluidized-bed combustor development

    International Nuclear Information System (INIS)

    1992-05-01

    Pulsed atmospheric fluidized-bed combustion (PAFBC) is a unique and innovative coal-fueled technology that has the potential to meet these conditions and provide heat and/or process steam to small industrial, commercial, institutional and residential complexes. The potential of Pulse Atmospheric Fluidized Bed Combustion (PAFBC) technology has been amply demonstrated under the sponsorship of a previous DOE/METC contract (DE-AC21-88MC25069). The environmental performance of a coal-fired laboratory-scale system (1.5 million British Thermal Units per hour) (MMBtu/hr) significantly surpassed that of conventional bubbling and circulating fluidized-bed combustion units (see Table 1 for performance comparison). Prompted by these encouraging results in combustion, sulfur capture, emissions control, and enhanced heat transfer, Island Creek Coal Company (ICC) and Baltimore Thermal Energy Corporation expressed interest in the technology and offered to participate by providing host sites for field testing. EA's have been submitted independently for each of these field test sites. This submission addresses the preliminary testing of the PAFBC unit at Manufacturing and Technology Conversion International's (MTCI) Baltimore, MD facility

  11. Develop of a model to minimize and to treat waste coming from the chemical laboratories

    International Nuclear Information System (INIS)

    Chacon Hernandez, M.

    2000-01-01

    They were investigated and proposed alternative of minimization and treatment of waste organic type coming from chemical laboratories, considering as alternative the disposition for the drainage, the chemical treatment of the waste, the disposition in sanitary fillers, the creation of a cellar to recycle material, the incineration, the distillation and the possibility to establish an agreement with the company Cements INCSA to discard the materials in the oven to cements of this enterprise. the methodology had as first stage the summary of information about the production of residuals for Investigation Center or Academic Unit. For this they were considered the laboratories of investigation of the CICA, CELEQ, CIPRONA, LAYAFA, and the laboratories of teaching of the sections of Organic Chemistry, Inorganic Chemistry, Physicochemical, Pharmacognosy, Drugs Analysis, Physicopharmacy, Histology and Physiology. Additionally, you considers the office of purveyor of the Microbiology School. Subsequently one carries out an analysis of costs to determine which waste constituted most of the waste generated by the University, as for cost and volume. Then, they were carried out classifications of the materials according to chemical approaches, classification of the NFPA and for data of combustion heats. Once carried out this classification and established the current situation of the laboratories considered as for handling and treatment of waste, they proceeded to evaluate and select treatment options and disposition of waste considering advantages and disadvantages as for implementation possibility and cost stops this way a minimization model and treatment that it can be implemented in the University to settle down [es

  12. Combustion of cork waste in a circulating fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Gulyurtlu, I.; Boavida, D.; Miranda, M.; Cabrita, I. [Dept. de Tecnologias de Combustao, ITE-INETI, Lisboa (Portugal); Abelha, P. [Coaltec e Ambiente, Lisboa (Portugal)

    1999-07-01

    There is currently an ongoing joint project between Portugal and Spain, which is being funded by the FAIR programme. The principal objective of the FAIR project is to investigate the application of the fluidised bed combustion (FBC) technology to burn cork wastes with the aim of overcoming the difficulties currently experienced in the cork processing industries. The combustion studies at INETI were carried out using the 300 kW{sub th} circulating fluidised bed facility. The combustor is square in cross section with each side being 0.3 m long. The combustor height is 5 m. The temperatures in the bed, the riser and that of the flue gases leaving the reactor were continuously monitored. The combustion gases leaving the reactor passed through the recycling cyclone first to capture most of particulates elutriated out of the combustor. The solid particles were intermittently collected for analysis to determine the amount of carbon present, which helped the combustion efficiency to be calculated. Instantaneous measurements of O{sub 2}, CO, CO{sub 2}, NO{sub x}, N{sub 2}O and SO{sub 2} present levels in the flue gases were also carried out. The combustion tests were done with both the cork waste dust and granular virgin cork. The difference is that cork dust gets contaminated during the process due to the use of various additives. Most of the combustion took place in the riser where the temperature was at times up to 523 K above that of the bed. The unburned carbon level was low ranging from about 1.5 to 2.% suggesting that most of the particles burned to completion in the riser. (orig.)

  13. Modeling Soil Organic Carbon at Regional Scale by Combining Multi-Spectral Images with Laboratory Spectra

    DEFF Research Database (Denmark)

    Peng, Yi; Xiong, Xiong; Adhikari, Kabindra

    2015-01-01

    the model developed from only RS data and ancillary environmental data (RMSE: 3.6%, R2: 0.46). Plant-available water (PAW) was the most important predictor for all the models because of its close relationship with soil organic matter content. Moreover, vegetation indices, such as the Normalized Difference......There is a great challenge in combining soil proximal spectra and remote sensing spectra to improve the accuracy of soil organic carbon (SOC) models. This is primarily because mixing of spectral data from different sources and technologies to improve soil models is still in its infancy. The first...... parameters and soil maps were compiled to predict topsoil SOC using Cubist regression and Bayesian kriging. The results showed that the model developed from RS data, ancillary environmental data and laboratory spectral data yielded a lower root mean square error (RMSE) (2.8%) and higher R2 (0.59) than...

  14. Refractory experience in circulating fluidized bed combustors, Task 7

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, R.Q.

    1989-11-01

    This report describes the results of an investigation into the status of the design and selection of refractory materials for coal-fueled circulating fluidized-bed combustors. The survey concentrated on operating units in the United States manufactured by six different boiler vendors: Babcock and Wilcox, Combustion Engineering, Foster Wheeler, Keeler Dorr-Oliver, Pyropower, and Riley Stoker. Information was obtained from the boiler vendors, refractory suppliers and installers, and the owners/operators of over forty units. This work is in support of DOE's Clean Coal Technology program, which includes circulating fluidized-bed technology as one of the selected concepts being evaluated.

  15. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    Science.gov (United States)

    Sun, Jiangang G.; Verrilli, Michael J.; Stephan, Robert R.; Barnett, Terry R.; Ojard, Greg C.

    2003-01-01

    Combustor liners fabricated from a SiC/SiC composite (silicon carbide fibers in a silicon carbide matrix) were nondestructively interrogated before and after combustion rig testing by x-ray, ultrasonic, and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications correlated with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations.

  16. Survey of biomedical and environental data bases, models, and integrated computer systems at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Murarka, I.P.; Bodeau, D.J.; Scott, J.M.; Huebner, R.H.

    1978-08-01

    This document contains an inventory (index) of information resources pertaining to biomedical and environmental projects at Argonne National Laboratory--the information resources include a data base, model, or integrated computer system. Entries are categorized as models, numeric data bases, bibliographic data bases, or integrated hardware/software systems. Descriptions of the Information Coordination Focal Point (ICFP) program, the system for compiling this inventory, and the plans for continuing and expanding it are given, and suggestions for utilizing the services of the ICFP are outlined.

  17. New model for public participation at Sandia National Laboratories: What comes after environmental restoration?

    International Nuclear Information System (INIS)

    KEENER R, WILLIAM; BACA, STEPHEN S.; BACA, MAUREEN R.; STOTTS, AL; TOOPS, TAMI; WOLFF, THEODORE A.

    2000-01-01

    As the Sandia National Laboratories' Environmental Restoration (ER) project moves toward closure, the project's experiences--including a number of successes in the public participation arena--suggest it is time for a new, more interactive model for future government-citizen involvement. This model would strive to improve the quality of public interaction with the Department of Energy (DOE) and Sandia, by using subject-specific working groups and aiming for long-term trustful relationships with the community. It would make use of interactive techniques, fewer formal public forums, and a variety of polling and communication technologies to improve information gathering and exchange

  18. Survey of biomedical and environental data bases, models, and integrated computer systems at Argonne National Laboratory

    International Nuclear Information System (INIS)

    Murarka, I.P.; Bodeau, D.J.; Scott, J.M.; Huebner, R.H.

    1978-08-01

    This document contains an inventory (index) of information resources pertaining to biomedical and environmental projects at Argonne National Laboratory--the information resources include a data base, model, or integrated computer system. Entries are categorized as models, numeric data bases, bibliographic data bases, or integrated hardware/software systems. Descriptions of the Information Coordination Focal Point (ICFP) program, the system for compiling this inventory, and the plans for continuing and expanding it are given, and suggestions for utilizing the services of the ICFP are outlined

  19. Coal desulfurization in a rotary kiln combustor. Quarterly report No. 1, April 16, 1990--July 15, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, J.T. Jr.

    1990-08-15

    BCR National Laboratory (BCRNL) has initiated a project aimed at evaluating the technical and economic feasibility of using a rotary kiln, suitably modified, to burn Pennsylvania anthracite wastes, co-fired with high-sulfur bituminous coal. Limestone will be injected into the kiln for sulfur control, to determine whether high sulfur capture levels can be achieved with high sorbent utilization. The principal objectives of this work are: (1) to prove the feasibility of burning anthracite refuse, with co-firing of high-sulfur bituminous coal and with limestone injection for sulfur emissions control, in a rotary kiln fitted with a Universal Energy International (UEI) air injector system; (2) to determine the emissions levels of SO{sub x} and NO{sub x} and specifically to identify the Ca/S ratios that are required to meet New Source Performance Standards; (3) to evaluate the technical and economic merits of a commercial rotary kiln combustor in comparison to fluidized bed combustors; and, (4) to ascertain the need for further work, including additional combustion tests, prior to commercial application, and to recommend accordingly a detailed program towards this end.

  20. Cross-flow turbines: progress report on physical and numerical model studies at large laboratory scale

    Science.gov (United States)

    Wosnik, Martin; Bachant, Peter

    2016-11-01

    Cross-flow turbines show potential in marine hydrokinetic (MHK) applications. A research focus is on accurately predicting device performance and wake evolution to improve turbine array layouts for maximizing overall power output, i.e., minimizing wake interference, or taking advantage of constructive wake interaction. Experiments were carried with large laboratory-scale cross-flow turbines D O (1 m) using a turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. Several turbines of varying solidity were employed, including the UNH Reference Vertical Axis Turbine (RVAT) and a 1:6 scale model of the DOE-Sandia Reference Model 2 (RM2) turbine. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier-Stokes models. Results are presented for the simulation of performance and wake dynamics of cross-flow turbines and compared with experiments and body-fitted mesh, blade-resolving CFD. Supported by NSF-CBET Grant 1150797, Sandia National Laboratories.

  1. Modeling Photosensitized Secondary Organic Aerosol Formation in Laboratory and Ambient Aerosols.

    Science.gov (United States)

    Tsui, William G; Rao, Yi; Dai, Hai-Lung; McNeill, V Faye

    2017-07-05

    Photosensitized reactions involving imidazole-2-carboxaldehyde (IC) have been experimentally observed to contribute to secondary organic aerosol (SOA) growth. However, the extent of photosensitized reactions in ambient aerosols remains poorly understood and unaccounted for in atmospheric models. Here we use GAMMA 4.0, a photochemical box model that couples gas-phase and aqueous-phase aerosol chemistry, along with recent laboratory measurements of the kinetics of IC photochemistry, to analyze IC-photosensitized SOA formation in laboratory and ambient settings. Analysis of the laboratory results of Aregahegn et al. (2013) suggests that photosensitized production of SOA from limonene, isoprene, α-pinene, β-pinene, and toluene by 3 IC* occurs at or near the surface of the aerosol particle. Reactive uptake coefficients were derived from the experimental data using GAMMA 4.0. Simulations of aqueous aerosol SOA formation at remote ambient conditions including IC photosensitizer chemistry indicate less than 0.3% contribution to SOA growth from direct reactions of 3 IC* with limonene, isoprene, α-pinene, β-pinene, and toluene, and an enhancement of less than 0.04% of SOA formation from other precursors due to the formation of radicals in the bulk aerosol aqueous phase. Other, more abundant photosensitizer species, such as humic-like substances (HULIS), may contribute more significantly to aqueous aerosol SOA production.

  2. Integration of Diagnostic Microbiology in a Model of Total Laboratory Automation.

    Science.gov (United States)

    Da Rin, Giorgio; Zoppelletto, Maira; Lippi, Giuseppe

    2016-02-01

    Although automation has become widely utilized in certain areas of diagnostic testing, its adoption in diagnostic microbiology has proceeded much more slowly. To describe our real-world experience of integrating an automated instrument for diagnostic microbiology (Walk-Away Specimen Processor, WASPLab) within a model of total laboratory automation (TLA). The implementation process was divided into 2 phases. The former period, lasting approximately 6 weeks, entailed the installation of the WASPLab processor to operate as a stand-alone instrumentation, whereas the latter, lasting approximately 2 weeks, involved physical connection of the WASPLab with the automation. Using the WASPLab instrument in conjunction with the TLA model, we obtained a time savings equivalent to the work of 1.2 full-time laboratory technicians for diagnostic microbiology. The connection of WASPLab to TLA allowed its management by a generalist or clinical chemistry technician, with no need for microbiology skills on the part of either worker. Hence, diagnostic microbiology could be performed by the staff that is already using the TLA, extending their activities to include processing urgent clinical chemistry and hematology specimens. The time to result was also substantially improved. According to our experience, using the WASPLab instrument as part of a TLA in diagnostic microbiology holds great promise for optimizing laboratory workflow and improving the quality of testing. © American Society for Clinical Pathology, 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Customer service model for waste tracking at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Dorries, Alison M.; Montoya, Andrew J.; Ashbaugh, Andrew E.

    2010-01-01

    The deployment of any new software system in a production facility will always face multiple hurtles in reaching a successful acceptance. However, a new waste tracking system was required at the plutonium processing facility at Los Alamos National Laboratory (LANL) where waste processing must be integrated to handle Special Nuclear Materials tracking requirements. Waste tracking systems can enhance the processing of waste in production facilities when the system is developed with a focus on customer service throughout the project life cycle. In March 2010 Los Alamos National Laboratory Waste Technical Services (WTS) replaced the aging systems and infrastructure that were being used to support the plutonium processing facility. The Waste Technical Services (WTS) Waste Compliance and Tracking System (WCATS) Project Team, using the following customer service model, succeeded in its goal to meet all operational and regulatory requirements, making waste processing in the facility more efficient while partnering with the customer.

  4. Crossing the barrier between the laboratory working model and the practicable production model

    Science.gov (United States)

    Curby, William A.

    1992-12-01

    Transforming apparatus that has developed into a successfully working laboratory system into a system that is ready, or nearly ready for production, distribution and general use is not always accomplished in a cost effective or timely fashion. Several design elements must be considered interactively during the planning, construction, use and servicing of the final production form of the system. The basic design elements are: Operating Specifications, Reliability Factors, Safety Factors, Precision Limits, Accuracy Limits, Uniformity Factors, Cost Limits and Calibration Requirements. Secondary elements including: Human Engineering, Documentation, Training, Maintenance, Proprietary Rights, Protection, Marketing, Replacement of Parts, and Packing and Shipping must also be considered during the transition.

  5. Thermal performance of a meso-scale liquid-fuel combustor

    International Nuclear Information System (INIS)

    Vijayan, V.; Gupta, A.K.

    2011-01-01

    Research highlights: → Demonstrated successful combustion of liquid fuel-air mixtures in a novel meso-scale combustor. → Flame quenching was eliminated using heat recirculation in a swiss roll type combustor that also extended the flammability limits. → Liquid fuel was rapidly vaporized with the use of hot narrow channel walls that eliminated the need of a fuel atomizer. → Maximum power density of the combustor was estimated to be about 8.5 GW/m3 and heat load in the range of 50-280W. → Overall efficiency of the combustor was estimated in the range of 12 to 20%. - Abstract: Combustion in small scale devices poses significant challenges due to the quenching of reactions from wall heat losses as well as the significantly reduced time available for mixing and combustion. In the case of liquid fuels there are additional challenges related to atomization, vaporization and mixing with the oxidant in the very short time-scale liquid-fuel combustor. The liquid fuel employed here is methanol with air as the oxidizer. The combustor was designed based on the heat recirculating concept wherein the incoming reactants are preheated by the combustion products through heat exchange occurring via combustor walls. The combustor was fabricated from Zirconium phosphate, a ceramic with very low thermal conductivity (0.8 W m -1 K -1 ). The combustor had rectangular shaped double spiral geometry with combustion chamber in the center of the spiral formed by inlet and exhaust channels. Methanol and air were introduced immediately upstream at inlet of the combustor. The preheated walls of the inlet channel also act as a pre-vaporizer for liquid fuel which vaporizes the liquid fuel and then mixes with air prior to the fuel-air mixture reaching the combustion chamber. Rapid pre-vaporization of the liquid fuel by the hot narrow channel walls eliminated the necessity for a fuel atomizer. Self-sustained combustion of methanol-air was achieved in a chamber volume as small as 32.6 mm 3

  6. The seismic cycle at subduction thrusts: 2. Dynamic implications of geodynamic simulations validated with laboratory models

    KAUST Repository

    van Dinther, Y.

    2013-04-01

    The physics governing the seismic cycle at seismically active subduction zones remains poorly understood due to restricted direct observations in time and space. To investigate subduction zone dynamics and associated interplate seismicity, we validate a continuum, visco-elasto-plastic numerical model with a new laboratory approach (Paper 1). The analogous laboratory setup includes a visco-elastic gelatin wedge underthrusted by a rigid plate with defined velocity-weakening and -strengthening regions. Our geodynamic simulation approach includes velocity-weakening friction to spontaneously generate a series of fast frictional instabilities that correspond to analog earthquakes. A match between numerical and laboratory source parameters is obtained when velocity-strengthening is applied in the aseismic regions to stabilize the rupture. Spontaneous evolution of absolute stresses leads to nucleation by coalescence of neighboring patches, mainly occurring at evolving asperities near the seismogenic zone limits. Consequently, a crack-, or occasionally even pulse-like, rupture propagates toward the opposite side of the seismogenic zone by increasing stresses ahead of its rupture front, until it arrests on a barrier. The resulting surface displacements qualitatively agree with geodetic observations and show landward and, from near the downdip limit, upward interseismic motions. These are rebound and reversed coseismically. This slip increases adjacent stresses, which are relaxed postseismically by afterslip and thereby produce persistent seaward motions. The wide range of observed physical phenomena, including back-propagation and repeated slip, and the agreement with laboratory results demonstrate that visco-elasto-plastic geodynamic models with rate-dependent friction form a new tool that can greatly contribute to our understanding of the seismic cycle at subduction zones.

  7. Development Report on the Idaho National Laboratory Sitewide Three-Dimensional Aquifer Model

    Energy Technology Data Exchange (ETDEWEB)

    Thomas R. Wood; Catherine M. Helm-Clark; Hai Huang; Swen Magnuson; Travis McLing; Brennon Orr; Michael J. Rohe; Mitchell A. Plummer; Robert Podgorney; Erik Whitmore; Michael S. Roddy

    2007-09-01

    A sub-regional scale, three-dimensional flow model of the Snake River Plain Aquifer was developed to support remediation decisions for Waste Area Group 10, Operable Unit 10 08 at the Idaho National Laboratory (INL) Site. This model has been calibrated primarily to water levels and secondarily to groundwater velocities interpreted from stable isotope disequilibrium studies and the movement of anthropogenic contaminants in the aquifer from facilities at the INL. The three-dimensional flow model described in this report is one step in the process of constructing a fully three-dimensional groundwater flow and contaminant transport model as prescribed in the Idaho National Engineering and Environmental Laboratory Operable Unit 10-08 Sitewide Groundwater Model Work Plan. An updated three-dimensional hydrogeologic conceptual model is presented along with the geologic basis for the conceptual model. Sediment-dominated three-dimensional volumes were used to represent the geology and constrain groundwater flow as part of the conceptual model. Hydrological, geochemical, and geological data were summarized and evaluated to infer aquifer behavior. A primary observation from development and evaluation of the conceptual model was that relative to flow on a regional scale, the aquifer can be treated with steady-state conditions. Boundary conditions developed for the three-dimensional flow model are presented along with inverse simulations that estimate parameterization of hydraulic conductivity. Inverse simulations were performed using the pilot-point method to estimate permeability distributions. Thermal modeling at the regional aquifer scale and at the sub-regional scale using the inverted permeabilities is presented to corroborate the results of the flow model. The results from the flow model show good agreement with simulated and observed water levels almost always within 1 meter. Simulated velocities show generally good agreement with some discrepancies in an interpreted low

  8. Laboratory cohabitation challenge model for shrimp hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP).

    Science.gov (United States)

    Salachan, Paul Vinu; Jaroenlak, Pattana; Thitamadee, Siripong; Itsathitphaisarn, Ornchuma; Sritunyalucksana, Kallaya

    2017-01-05

    Enterocytozoon hepatopenaei (EHP) causes hepatopancreatic microsporidiosis (HPM) in shrimp. It is probably endemic in Australasia and was first characterized and named from the giant or black tiger shrimp Penaeus monodon from Thailand in 2009. Later, it was also found to infect exotic Penaeus vannamei imported for cultivation in Asia. HPM is not normally associated with shrimp mortality, but information from shrimp farmers indicates that it is associated with significant growth retardation that is not clearly noticeable until 2-3 months of cultivation. In order to study modes of HPM transmission and to test possible control measures, a laboratory challenge model was needed that would mimic the mode of infection in shrimp ponds. We describe successful transmission in a cohabitation model with natural E. hepatopenaei (EHP)-infected shrimp in closed, perforated plastic containers placed in aquaria together with free-swimming, uninfected shrimp. After a period of 14 days all the free-swimming shrimp tested positive by PCR (approximately 60% with heavy infections evident by 1-step PCR positive test results) and gave positive histological and in situ hybridization results for E. hepatopenaei (EHP) in the hepatopancreas. A laboratory cohabitation model for studying E. hepatopenaei (EHP) has been developed and used to confirm that E. hepatopenaei (EHP) can be directly transmitted horizontally among shrimp via water. The model will facilitate studies on methods to prevent the E. hepatopenaei (EHP) transmission.

  9. Examination of the interpersonal model of loss of control eating in the laboratory.

    Science.gov (United States)

    Shank, Lisa M; Crosby, Ross D; Grammer, Anne Claire; Shomaker, Lauren B; Vannucci, Anna; Burke, Natasha L; Stojek, Monika; Brady, Sheila M; Kozlosky, Merel; Reynolds, James C; Yanovski, Jack A; Tanofsky-Kraff, Marian

    2017-07-01

    The interpersonal model of loss of control (LOC) eating proposes that interpersonal problems lead to negative affect, which in turn contributes to the onset and/or persistence of LOC eating. Despite preliminary support, there are no data examining the construct validity of the interpersonal model of LOC eating using temporally sensitive reports of social stress, distinct negative affective states, and laboratory energy intake. 117 healthy adolescent girls (BMI: 75th-97th %ile) were recruited for a prevention trial targeting excess weight gain in adolescent girls who reported LOC eating. Prior to the intervention, participants completed questionnaires of recent social stress and consumed lunch from a multi-item laboratory test meal. Immediately before the test meal, participants completed a questionnaire of five negative affective states (anger, confusion, depression, fatigue, anxiety). Bootstrapping mediation models were conducted to evaluate pre-meal negative affect states as explanatory mediators of the association between recent social stress and palatable (desserts and snack-type) food intake. All analyses adjusted for age, race, pubertal stage, height, fat mass percentage, and lean mass. Pre-meal state anxiety was a significant mediator for recent social stress and palatable food intake (ps.05). Pre-meal anxiety appears to be the salient mood state for the interpersonal model among adolescent girls with LOC eating. Interventions that focus on improving both social functioning and anxiety may prove most effective at preventing and/or ameliorating disordered eating and obesity in these adolescents. Published by Elsevier Inc.

  10. Application of a learning model in a traditional engineering classroom and laboratory

    Science.gov (United States)

    Brown, Cordelia Magalene

    The purpose of this dissertation research was to develop a learning model. This three-phase learning model involved administering pre-assessment inventories, facilitating collaborative exercises, and evaluating learning experiences. This dissertation explores the potential effects the learning model might have on course performance and overall academic performance. It focuses on potential relationships between course performance and learning style preferences data, demographics, and level of participation in phases of the learning model. It also examines relationships between confidence levels and the performance of course objectives. The first and final phases were applied to an introductory Electrical Engineering course. The second phase was applied to selected sections of the course. In the initial phase, students in all sections of the course were administered the Index of Learning Styles Questionnaire, a Myers-Briggs Type Indicator, and a pre-laboratory evaluation. In the second phase of the learning model, the students in the selected sections participated in weekly learning sessions. The weekly learning sessions provided students with practice problem sets and a structured environment to collaboratively practice problems and discuss course concepts. The final phase of the learning model evaluated the performance of students in both environments. From the application of the learning model, the effects that various instructional methods would have on students' performance in a laboratory type of environment were investigated. Overall, students that participated in the weekly learning sessions earned grades that were comparable or better than non-participants. Participants and non-participants in the weekly learning sessions with the Myers-Briggs Type Indicator (MBTI) Engineering Type (INTJ or ISTJ) earned about the same grade. Participants in the weekly learning sessions with types other than MBTI Engineering Type outperformed their peers of the same MBTI type

  11. Coal-fired MHD combustor development project: Phase 3D

    Science.gov (United States)

    1985-05-01

    This fourth quarterly technical progress report of the Coal-Fired MHD Combustor Development Project (Phase 3D) presents the accomplishments during the period February 1 to April 30, 1985. The scope of work covered by this quarterly report encompasses development work on the 50 MW/sub t/ combustor related to test support at the CDIF, assembly and checkout of first and second stage hardware, second stage design verification testing, designs for a continuous slag rejector and low preheat inlet section, and planning for power train testing. Progress includes the following: assembly and checkout of the second first stage, two second stages, and PEM was completed and the hardware was shipped to CDIF and FETS; integration of first and second stage hardware on the FETS Cell No. 2 test stand was completed, cold flow functional tests were performed, and hot fire checkout testing was initiated; assembly of the continuous slag rejector test set-up was 70% completed; the low preheat air inlet section Preliminary Design Review was held (work on the detail design was initiated and is 85% complete); and the Users' Manual was updated to include material for the second stage and final revisions to the power train test plan were made.

  12. Combustion Dynamics in Multi-Nozzle Combustors Operating on High-Hydrogen Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Santavicca, Dom; Lieuwen, Tim

    2013-09-30

    Actual gas turbine combustors for power generation applications employ multi-nozzle combustor configurations. Researchers at Penn State and Georgia Tech have extended previous work on the flame response in single-nozzle combustors to the more realistic case of multi-nozzle combustors. Research at Georgia Tech has shown that asymmetry of both the flow field and the acoustic forcing can have a significant effect on flame response and that such behavior is important in multi-flame configurations. As a result, the structure of the flame and its response to forcing is three-dimensional. Research at Penn State has led to the development of a three-dimensional chemiluminescence flame imaging technique that can be used to characterize the unforced (steady) and forced (unsteady) flame structure of multi-nozzle combustors. Important aspects of the flame response in multi-nozzle combustors which are being studied include flame-flame and flame-wall interactions. Research at Penn State using the recently developed three-dimensional flame imaging technique has shown that spatial variations in local flame confinement must be accounted for to accurately predict global flame response in a multi-nozzle can combustor.

  13. A laboratory-calibrated model of coho salmon growth with utility for ecological analyses

    Science.gov (United States)

    Manhard, Christopher V.; Som, Nicholas A.; Perry, Russell W.; Plumb, John M.

    2018-01-01

    We conducted a meta-analysis of laboratory- and hatchery-based growth data to estimate broadly applicable parameters of mass- and temperature-dependent growth of juvenile coho salmon (Oncorhynchus kisutch). Following studies of other salmonid species, we incorporated the Ratkowsky growth model into an allometric model and fit this model to growth observations from eight studies spanning ten different populations. To account for changes in growth patterns with food availability, we reparameterized the Ratkowsky model to scale several of its parameters relative to ration. The resulting model was robust across a wide range of ration allocations and experimental conditions, accounting for 99% of the variation in final body mass. We fit this model to growth data from coho salmon inhabiting tributaries and constructed ponds in the Klamath Basin by estimating habitat-specific indices of food availability. The model produced evidence that constructed ponds provided higher food availability than natural tributaries. Because of their simplicity (only mass and temperature are required as inputs) and robustness, ration-varying Ratkowsky models have utility as an ecological tool for capturing growth in freshwater fish populations.

  14. Simulation of the hydraulic performance of highway filter drains through laboratory models and stormwater management tools.

    Science.gov (United States)

    Sañudo-Fontaneda, Luis A; Jato-Espino, Daniel; Lashford, Craig; Coupe, Stephen J

    2017-05-23

    Road drainage is one of the most relevant assets in transport infrastructure due to its inherent influence on traffic management and road safety. Highway filter drains (HFDs), also known as "French Drains", are the main drainage system currently in use in the UK, throughout 7000 km of its strategic road network. Despite being a widespread technique across the whole country, little research has been completed on their design considerations and their subsequent impact on their hydraulic performance, representing a gap in the field. Laboratory experiments have been proven to be a reliable indicator for the simulation of the hydraulic performance of stormwater best management practices (BMPs). In addition to this, stormwater management tools (SMT) have been preferentially chosen as a design tool for BMPs by practitioners from all over the world. In this context, this research aims to investigate the hydraulic performance of HFDs by comparing the results from laboratory simulation and two widely used SMT such as the US EPA's stormwater management model (SWMM) and MicroDrainage®. Statistical analyses were applied to a series of rainfall scenarios simulated, showing a high level of accuracy between the results obtained in laboratory and using SMT as indicated by the high and low values of the Nash-Sutcliffe and R 2 coefficients and root-mean-square error (RMSE) reached, which validated the usefulness of SMT to determine the hydraulic performance of HFDs.

  15. Hydrogeological characterization, modelling and monitoring of the site of Canada's Underground Research Laboratory

    International Nuclear Information System (INIS)

    Davison, C.C.; Guvanasen, V.

    1985-01-01

    Atomic Energy of Canada Limited (AECL) is constructing an Underground Research Laboratory (URL) to a depth of 250 m in a previously undisturbed granitic pluton located near Lac du Bonnet, Manitoba, as one of the major research projects within the Canadian Nuclear Fuel Waste Management Program. This paper discusses the hydrogeological characterization of the URL site, the modelling approach used to represent this information, the hydrogeological monitoring system installed to monitor the actual drawdown conditions that develop in response to the excavation, and the procedures employed to calibrate the numerical model. Comparisons between the drawdown predictions made by the model prior to any excavation and the actual drawdowns that have been measured since shaft excavation began in May 1984 are also discussed

  16. Reactive transport modeling of multicomponent cation exchange at the laboratory and field scale

    International Nuclear Information System (INIS)

    Steefel, Carl I.

    2004-01-01

    Multicomponent ion exchange models have been successful in describing the chromatographic separation of cations in both laboratory and field settings. Their chief advantage lies in their ability to capture the competitive effects of other cations that may be present. By incorporating exchanger activity coefficients calculated on the basis of the Gibbs-Duhem equation applied to the exchanger phase, it is possible to correct for the non-ideality of exchange. The use of multiple exchange sites can also substantially improve the ability of the cation exchange models to describe adsorption and retardation. All of these benefits are associated with relatively little additional computational burden. Even where the cost of the multicomponent cation exchange calculations are considered too high, the models are useful in calculating distribution coefficients for the environmental conditions of interest

  17. Design Optimization of a Micro-Combustor for Lean, Premixed Fuel-Air Mixtures

    Science.gov (United States)

    Powell, Leigh Theresa

    Present technology has been shifting towards miniaturization of devices for energy production for portable electronics. Micro-combustors, when incorporated into a micro-power generation system, provide the energy desired in the form of hot gases to power such technology. This creates the need for a design optimization of the micro-combustor in terms of geometry, fuel choice, and material selection. A total of five micro-combustor geometries, three fuels, and three materials were computationally simulated in different configurations in order to determine the optimal micro-combustor design for highest efficiency. Inlet velocity, equivalence ratio, and wall heat transfer coefficient were varied in order to test a comprehensive range of micro-combustor parameters. All simulations completed for the optimization study used ANSYS Fluent v16.1 and post-processing of the data was done in CFD Post v16.1. It was found that for lean, premixed fuel-air mixtures (φ = 0.6 - 0.9) ethane (C 2H6) provided the highest flame temperatures when ignited within the micro-combustor geometries. An aluminum oxide converging micro-combustor burning ethane and air at an equivalence ratio of 0.9, an inlet velocity of 0.5 m/s, and heat transfer coefficient of 5 W/m2-K was found to produce the highest combustor efficiency, making it the optimal choice for a micro-combustor design. It is proposed that this geometry be experimentally and computationally investigated further in order to determine if additional optimization can be achieved.

  18. Extreme Adiabatic Expansion in Micro-gravity: Modeling for the Cold Atomic Laboratory

    Science.gov (United States)

    Sackett, C. A.; Lam, T. C.; Stickney, J. C.; Burke, J. H.

    2017-12-01

    The upcoming Cold Atom Laboratory mission for the International Space Station will allow the investigation of ultracold gases in a microgravity environment. Cold atomic samples will be produced using evaporative cooling in a magnetic chip trap. We investigate here the possibility to release atoms from the trap via adiabatic expansion. We discuss both general considerations and a detailed model of the planned apparatus. We find that it should be possible to reduce the mean trap confinement frequency to about 0.2 Hz, which will correspond to a three-dimensional sample temperature of about 150 pK and a mean atom velocity of 0.1 mm/s.

  19. Laboratory and Modeling Evaluations in Support of Field Testing for Desiccation at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J.; Oostrom, Martinus; Freedman, Vicky L.; Strickland, Christopher E.; Wietsma, Thomas W.; Tartakovsky, Guzel D.; Ward, Anderson L.

    2011-02-23

    The Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau includes testing of the desiccation technology as a potential technology to be used in conjunction with surface infiltration control to limit the flux of technetium and other contaminants in the vadose zone to the groundwater. Laboratory and modeling efforts were conducted to investigate technical uncertainties related to the desiccation process and its impact on contaminant transport. This information is intended to support planning, operation, and interpretation of a field test for desiccation in the Hanford Central Plateau.

  20. Laboratory Modeling of Self-Formed Leveed Channels From Sediment-Laden Flows Entering Still Water

    Science.gov (United States)

    Rowland, J. C.; Dietrich, W. E.

    2004-12-01

    Self-formed leveed channels constructed by deposition of suspended sediment from sediment-laden flows entering still water are common features in nature. Such channels drive delta progradation, develop at tidal inlets and occur where mainstem river flows empty into oxbows and blocked valley lakes. Presently there is no theory for the formation of such channels. This lack of theory is partly due to a lack of field or laboratory studies that provide insight about the mechanism controlling these self-formed, propagating channels. The creation of such features in the laboratory, have proved illusive to date. Our ongoing experiments aimed at modeling the formation of floodplain tie channels provide insight into the necessary conditions for levee formation and channel growth. Under conditions of steady water discharge, constant sediment feed rate, unimodal sediment distribution and invariant basin stage we are able to create subaqueous lateral bars (submerged levees) along the margins of a sediment laden jet. Our results highlight the sensitivity of channel formation to issues of scaling and experimental design. In the laboratory, levee formation has only been possible with the use of plastic particles (specific gravity ~1.5); complete bed alluviation and dune formation results from the use of particles with specific gravities of ~ 2.65 across a range grain diameters and shapes. We hypothesize this effect is related to high entrainment thresholds relative to suspension thresholds of small (< 100 mm) natural particles under conditions of reduced turbulence in laboratory scaled flows. Additionally, both the width to depth ratio and the form of the outlet channel introducing the sediment laden flow into the experimental basin exert a strong control on sedimentation pattern and levee growth. Continuing experiments are focused on generating emergent channel levees and a basin ward propagation of the channel by adjusting the form of the feed channel, varying basin stage, and

  1. A parametric study on the effect of an acoustic field on a spray-fired, Rijke-tube, pulse combustor

    Science.gov (United States)

    Dubey, Raj Kumar

    A parametric experimental and theoretical study was performed to investigate the effects of an acoustic field on spray combustion characteristics. A Rijke-tube pulse combustor was constructed with variable length and a fixed diameter. A burner was designed for use with both gaseous and liquid fuel. An active control mechanism was implemented to externally control the acoustic field inside the combustor, as it was not possible to sustain natural oscillations with the long spray flame. Active control of the combustor was characterized for gaseous and spray flames applying both indirect control (in-line actuators) as well as direct control using external speakers. The size and velocity distribution of a nonreacting and reacting spray in an actively controlled acoustic field were measured using a two-component phase-Doppler particle analyzer (PDPA). The effects of burner location, frequency, and sound pressure level on the spray size and velocity distribution were studied. Based on the measured trends in the Dsb{32}, velocity, and data rate, mechanisms governing the interactions of the acoustic field with the spray were identified. These include atomization, evaporation and reaction, dispersion, droplet lifetime and flame lift. Also, the faster burning of the droplets was more prominent when the spray was placed at locations corresponding to the acoustic velocity antinode. A significant decrease in CO and NO emissions were found in the presence of an acoustic field as compared to the steady operation of the combustor. A mathematical model was developed to study the effects of frequency, sound pressure level, phase lag of droplet injection with respect to the acoustic velocity field, droplet injection velocity, and surrounding gas velocity on the Sauter-mean diameter of a reacting ethanol spray. The enhanced burning of the droplets are indicated by model results with higher initial slopes in the Dsb{32} profiles along the axial direction. For burner locations

  2. TOUGH-RBSN simulator for hydraulic fracture propagation within fractured media: Model validations against laboratory experiments

    Science.gov (United States)

    Kim, Kunhwi; Rutqvist, Jonny; Nakagawa, Seiji; Birkholzer, Jens

    2017-11-01

    This paper presents coupled hydro-mechanical modeling of hydraulic fracturing processes in complex fractured media using a discrete fracture network (DFN) approach. The individual physical processes in the fracture propagation are represented by separate program modules: the TOUGH2 code for multiphase flow and mass transport based on the finite volume approach; and the rigid-body-spring network (RBSN) model for mechanical and fracture-damage behavior, which are coupled with each other. Fractures are modeled as discrete features, of which the hydrological properties are evaluated from the fracture deformation and aperture change. The verification of the TOUGH-RBSN code is performed against a 2D analytical model for single hydraulic fracture propagation. Subsequently, modeling capabilities for hydraulic fracturing are demonstrated through simulations of laboratory experiments conducted on rock-analogue (soda-lime glass) samples containing a designed network of pre-existing fractures. Sensitivity analyses are also conducted by changing the modeling parameters, such as viscosity of injected fluid, strength of pre-existing fractures, and confining stress conditions. The hydraulic fracturing characteristics attributed to the modeling parameters are investigated through comparisons of the simulation results.

  3. A Wildfire Behavior Modeling System at Los Alamos National Laboratory for Operational Applications

    Energy Technology Data Exchange (ETDEWEB)

    S.W. Koch; R.G.Balice

    2004-11-01

    To support efforts to protect facilities and property at Los Alamos National Laboratory from damages caused by wildfire, we completed a multiyear project to develop a system for modeling the behavior of wildfires in the Los Alamos region. This was accomplished by parameterizing the FARSITE wildfire behavior model with locally gathered data representing topography, fuels, and weather conditions from throughout the Los Alamos region. Detailed parameterization was made possible by an extensive monitoring network of permanent plots, weather towers, and other data collection facilities. We also incorporated a database of lightning strikes that can be used individually as repeatable ignition points or can be used as a group in Monte Carlo simulation exercises and in other randomization procedures. The assembled modeling system was subjected to sensitivity analyses and was validated against documented fires, including the Cerro Grande Fire. The resulting modeling system is a valuable tool for research and management. It also complements knowledge based on professional expertise and information gathered from other modeling technologies. However, the modeling system requires frequent updates of the input data layers to produce currently valid results, to adapt to changes in environmental conditions within the Los Alamos region, and to allow for the quick production of model outputs during emergency operations.

  4. Design and preliminary results of a fuel flexible industrial gas turbine combustor

    Science.gov (United States)

    Novick, A. S.; Troth, D. L.; Yacobucci, H. G.

    1981-01-01

    The design characteristics are presented of a fuel tolerant variable geometry staged air combustor using regenerative/convective cooling. The rich/quench/lean variable geometry combustor is designed to achieve low NO(x) emission from fuels containing fuel bound nitrogen. The physical size of the combustor was calculated for a can-annular combustion system with associated operating conditions for the Allison 570-K engine. Preliminary test results indicate that the concept has the potential to meet emission requirements at maximum continuous power operation. However, airflow sealing and improved fuel/air mixing are necessary to meet Department of Energy program goals.

  5. Quiet Clean Short-haul Experimental Engine (QCSEE). Double-annular clean combustor technology development report

    Science.gov (United States)

    Bahr, D. W.; Burrus, D. L.; Sabla, P. E.

    1979-01-01

    A sector combustor technology development program was conducted to define an advanced double annular dome combustor sized for use in the quiet clean short haul experimental engine (QCSEE). A design which meets the emission goals, and combustor performance goals of the QCSEE engine program was developed. Key design features were identified which resulted in substantial reduction in carbon monoxide and unburned hydrocarbon emission levels at ground idle operating conditions, in addition to very low nitric oxide emission levels at high power operating conditions. Their significant results are reported.

  6. Comparison of Model Predictions and Laboratory Observations of Transgene Frequencies in Continuously-Breeding Mosquito Populations

    Directory of Open Access Journals (Sweden)

    Laura Valerio

    2016-09-01

    Full Text Available The persistence of transgenes in the environment is a consideration in risk assessments of transgenic organisms. Combining mathematical models that predict the frequency of transgenes and experimental demonstrations can validate the model predictions, or can detect significant biological deviations that were neither apparent nor included as model parameters. In order to assess the correlation between predictions and observations, models were constructed to estimate the frequency of a transgene causing male sexual sterility in simulated populations of a malaria mosquito Anopheles gambiae that were seeded with transgenic females at various proportions. Concurrently, overlapping-generation laboratory populations similar to those being modeled were initialized with various starting transgene proportions, and the subsequent proportions of transgenic individuals in populations were determined weekly until the transgene disappeared. The specific transgene being tested contained a homing endonuclease gene expressed in testes, I-PpoI, that cleaves the ribosomal DNA and results in complete male sexual sterility with no effect on female fertility. The transgene was observed to disappear more rapidly than the model predicted in all cases. The period before ovipositions that contained no transgenic progeny ranged from as little as three weeks after cage initiation to as long as 11 weeks.

  7. Development of an experimental model of pemphigus vulgaris in laboratory animals

    Directory of Open Access Journals (Sweden)

    A. A. Kubanov

    2015-01-01

    Full Text Available Pemphigus vulgaris is a chronic autoimmune bullous disease characterized by the formation of blisters on the skin and/ or mucous tunics as a result of acantholysis. To search for new molecular and biological targets, study pathogenetic mechanisms of the disease development and develop new methods of treatment, it is urgent to create an experimental model of pemphigus in laboratory animals reproducing clinical, histological and immunological signs of pemphigus. Goal of the study. To develop an experimental model of pemphigus by injecting IgG produced from the blood serum taken from patients with pemphigus to neonatal mice of the BALB/c inbred line. Results. Accumulated IgG products taken from patients with pemphigus (main groups and healthy volunteers (control group were injected intraperitoneally to neonatal mice of the BALB/с in the doses of 10-30 mg per mouse. Clinical, histological and immunomorphological signs of pemphigus were revealed in the mice from the main group, which received intraperitoneal injections of IgG taken from patients with pemphigus in the dose of 30 mg per mouse. No signs of pemphigus were observed in the mice from the control group, which received injections of IgG taken from healthy people. This study confirms the role of pemphigus autoantibodies in the pathogenesis of pemphigus vulgaris and shows that passive transmission of antibodies to laboratory animals is possible.

  8. Savannah River Laboratory DOSTOMAN code: a compartmental pathways computer model of contaminant transport

    International Nuclear Information System (INIS)

    King, C.M.; Wilhite, E.L.; Root, R.W. Jr.

    1985-01-01

    The Savannah River Laboratory DOSTOMAN code has been used since 1978 for environmental pathway analysis of potential migration of radionuclides and hazardous chemicals. The DOSTOMAN work is reviewed including a summary of historical use of compartmental models, the mathematical basis for the DOSTOMAN code, examples of exact analytical solutions for simple matrices, methods for numerical solution of complex matrices, and mathematical validation/calibration of the SRL code. The review includes the methodology for application to nuclear and hazardous chemical waste disposal, examples of use of the model in contaminant transport and pathway analysis, a user's guide for computer implementation, peer review of the code, and use of DOSTOMAN at other Department of Energy sites. 22 refs., 3 figs

  9. Mathematical modeling of convective air drying of quinoa-supplemented feed for laboratory rats

    Directory of Open Access Journals (Sweden)

    Antonio Vega-Gálvez

    2011-02-01

    Full Text Available Drying kinetics of quinoa-supplemented feed for laboratory rats during processing at 50, 60, 70, 80 and 90ºC was studied and modeled in this work. Desorption isotherm was obtained at 60ºC giving a monolayer moisture content of 0.04 g water/g d.m. The experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying equations available in the literature were evaluated based on determination coefficient (r², sum squared errors (SSE and Chi-square (χ2 statisticals. In comparison to the experimental moisture values, the values estimated with the Logarithmic model gave the best fit quality (r² >0.994, SSE < 0.00015 and χ2 < 0.00018, showing this equation could predict very accurately the drying time of rat feed under the operative conditions applied.

  10. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2006-04-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  11. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2007-08-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  12. Strain Localization and Weakening Processes in Viscously Deforming Rocks: Numerical Modeling Based on Laboratory Torsion Experiments

    Science.gov (United States)

    Doehmann, M.; Brune, S.; Nardini, L.; Rybacki, E.; Dresen, G.

    2017-12-01

    Strain localization is an ubiquitous process in earth materials observed over a broad range of scales in space and time. Localized deformation and the formation of shear zones and faults typically involves material softening by various processes, like shear heating and grain size reduction. Numerical modeling enables us to study the complex physical and chemical weakening processes by separating the effect of individual parameters and boundary conditions. Using simple piece-wise linear functions for the parametrization of weakening processes allows studying a system at a chosen (lower) level of complexity (e.g. Cyprych et al., 2016). In this study, we utilize a finite element model to test two weakening laws that reduce the strength of the material depending on either the I) amount of accumulated strain or II) deformational work. Our 2D Cartesian models are benchmarked to single inclusion torsion experiments performed at elevated temperatures of 900 °C and pressures of up to 400 MPa (Rybacki et al., 2014). The experiments were performed on Carrara marble samples containing a weak Solnhofen limestone inclusion at a maximum strain rate of 2.0*10-4 s-1. Our models are designed to reproduce shear deformation of a hollow cylinder equivalent to the laboratory setup, such that material leaving one side of the model in shear direction enters again on the opposite side using periodic boundary conditions. Similar to the laboratory tests, we applied constant strain rate and constant stress boundary conditions.We use our model to investigate the time-dependent distribution of stress and strain and the effect of different parameters. For instance, inclusion rotation is shown to be strongly dependent on the viscosity ratio between matrix and inclusion and stronger ductile weakening increases the localization rate while decreasing shear zone width. The most suitable weakening law for representation of ductile rock is determined by combining the results of parameter tests with

  13. Damage severity assessment in wind turbine blade laboratory model through fuzzy finite element model updating

    Science.gov (United States)

    Turnbull, Heather; Omenzetter, Piotr

    2017-04-01

    The recent shift towards development of clean, sustainable energy sources has provided a new challenge in terms of structural safety and reliability: with aging, manufacturing defects, harsh environmental and operational conditions, and extreme events such as lightning strikes wind turbines can become damaged resulting in production losses and environmental degradation. To monitor the current structural state of the turbine, structural health monitoring (SHM) techniques would be beneficial. Physics based SHM in the form of calibration of a finite element model (FEMs) by inverse techniques is adopted in this research. Fuzzy finite element model updating (FFEMU) techniques for damage severity assessment of a small-scale wind turbine blade are discussed and implemented. The main advantage is the ability of FFEMU to account in a simple way for uncertainty within the problem of model updating. Uncertainty quantification techniques, such as fuzzy sets, enable a convenient mathematical representation of the various uncertainties. Experimental frequencies obtained from modal analysis on a small-scale wind turbine blade were described by fuzzy numbers to model measurement uncertainty. During this investigation, damage severity estimation was investigated through addition of small masses of varying magnitude to the trailing edge of the structure. This structural modification, intended to be in lieu of damage, enabled non-destructive experimental simulation of structural change. A numerical model was constructed with multiple variable additional masses simulated upon the blades trailing edge and used as updating parameters. Objective functions for updating were constructed and minimized using both particle swarm optimization algorithm and firefly algorithm. FFEMU was able to obtain a prediction of baseline material properties of the blade whilst also successfully predicting, with sufficient accuracy, a larger magnitude of structural alteration and its location.

  14. Validation of a Hot Water Distribution Model Using Laboratory and Field Data

    Energy Technology Data Exchange (ETDEWEB)

    Backman, C.; Hoeschele, M.

    2013-07-01

    Characterizing the performance of hot water distribution systems is a critical step in developing best practice guidelines for the design and installation of high performance hot water systems. Developing and validating simulation models is critical to this effort, as well as collecting accurate input data to drive the models. In this project, the ARBI team validated the newly developed TRNSYS Type 604 pipe model against both detailed laboratory and field distribution system performance data. Validation efforts indicate that the model performs very well in handling different pipe materials, insulation cases, and varying hot water load conditions. Limitations of the model include the complexity of setting up the input file and long simulation run times. In addition to completing validation activities, this project looked at recent field hot water studies to better understand use patterns and potential behavioral changes as homeowners convert from conventional storage water heaters to gas tankless units. Based on these datasets, we conclude that the current Energy Factor test procedure overestimates typical use and underestimates the number of hot water draws. This has implications for both equipment and distribution system performance. Gas tankless water heaters were found to impact how people use hot water, but the data does not necessarily suggest an increase in usage. Further study in hot water usage and patterns is needed to better define these characteristics in different climates and home vintages.

  15. Validation of a Hot Water Distribution Model Using Laboratory and Field Data

    Energy Technology Data Exchange (ETDEWEB)

    Backman, C. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2013-07-01

    Characterizing the performance of hot water distribution systems is a critical step in developing best practice guidelines for the design and installation of high performance hot water systems. Developing and validating simulation models is critical to this effort, as well as collecting accurate input data to drive the models. In this project, the Building America research team ARBI validated the newly developed TRNSYS Type 604 pipe model against both detailed laboratory and field distribution system performance data. Validation efforts indicate that the model performs very well in handling different pipe materials, insulation cases, and varying hot water load conditions. Limitations of the model include the complexity of setting up the input file and long simulation run times. This project also looked at recent field hot water studies to better understand use patterns and potential behavioral changes as homeowners convert from conventional storage water heaters to gas tankless units. The team concluded that the current Energy Factor test procedure overestimates typical use and underestimates the number of hot water draws, which has implications for both equipment and distribution system performance. Gas tankless water heaters were found to impact how people use hot water, but the data does not necessarily suggest an increase in usage. Further study in hot water usage and patterns is needed to better define these characteristics in different climates and home vintages.

  16. Constraining Carbonaceous Aerosol Climate Forcing by Bridging Laboratory, Field and Modeling Studies

    Science.gov (United States)

    Dubey, M. K.; Aiken, A. C.; Liu, S.; Saleh, R.; Cappa, C. D.; Williams, L. R.; Donahue, N. M.; Gorkowski, K.; Ng, N. L.; Mazzoleni, C.; China, S.; Sharma, N.; Yokelson, R. J.; Allan, J. D.; Liu, D.

    2014-12-01

    Biomass and fossil fuel combustion emits black (BC) and brown carbon (BrC) aerosols that absorb sunlight to warm climate and organic carbon (OC) aerosols that scatter sunlight to cool climate. The net forcing depends strongly on the composition, mixing state and transformations of these carbonaceous aerosols. Complexities from large variability of fuel types, combustion conditions and aging processes have confounded their treatment in models. We analyse recent laboratory and field measurements to uncover fundamental mechanism that control the chemical, optical and microphysical properties of carbonaceous aerosols that are elaborated below: Wavelength dependence of absorption and the single scattering albedo (ω) of fresh biomass burning aerosols produced from many fuels during FLAME-4 was analysed to determine the factors that control the variability in ω. Results show that ω varies strongly with fire-integrated modified combustion efficiency (MCEFI)—higher MCEFI results in lower ω values and greater spectral dependence of ω (Liu et al GRL 2014). A parameterization of ω as a function of MCEFI for fresh BB aerosols is derived from the laboratory data and is evaluated by field data, including BBOP. Our laboratory studies also demonstrate that BrC production correlates with BC indicating that that they are produced by a common mechanism that is driven by MCEFI (Saleh et al NGeo 2014). We show that BrC absorption is concentrated in the extremely low volatility component that favours long-range transport. We observe substantial absorption enhancement for internally mixed BC from diesel and wood combustion near London during ClearFlo. While the absorption enhancement is due to BC particles coated by co-emitted OC in urban regions, it increases with photochemical age in rural areas and is simulated by core-shell models. We measure BrC absorption that is concentrated in the extremely low volatility components and attribute it to wood burning. Our results support

  17. Ignition improvement by injector arrangement in a multi-fuel combustor for micro gas turbine

    Science.gov (United States)

    Antoshkiv, O.; Poojitganont, T.; Jeansirisomboon, S.; Berg, H. P.

    2018-01-01

    The novel combustor design also has an impact on the ignitor arrangement. The conventional ignitor system cannot guarantee optimal ignition performance in the usual radial position. The difficult ignitability of gaseous fuels was the main challenge for the ignitor system improvement. One way to improve the ignition performance significantly is a torch ignitor system in which the gaseous fuel is directly mixed with a large amount of the combustor air. To reach this goal, the ignition process was investigated in detail. The micro gas turbine (MGT) ignition was optimised considering three main procedures: torch ignitor operation, burner ignition and flame propagation between the neighbour injectors. A successful final result of the chain of ignition procedures depends on multiple aspects of the combustor design. Performed development work shows an important step towards designing modern high-efficiency low-emission combustors.

  18. System and method for reducing combustion dynamics and NO.sub.x in a combustor

    Science.gov (United States)

    Uhm, Jong H.; Johnson, Thomas Edward

    2015-11-20

    A system for reducing combustion dynamics and NO.sub.x in a combustor includes a tube bundle that extends radially across at least a portion of the combustor, wherein the tube bundle comprises an upstream surface axially separated from a downstream surface. A shroud circumferentially surrounds the upstream and downstream surfaces. A plurality of tubes extends through the tube bundle from the upstream surface through the downstream surface, wherein the downstream surface is stepped to produce tubes having different lengths through the tube bundle. A method for reducing combustion dynamics and NO.sub.x in a combustor includes flowing a working fluid through a plurality of tubes radially arranged between an upstream surface and a downstream surface of an end cap that extends radially across at least a portion of the combustor, wherein the downstream surface is stepped.

  19. Effect of Surface Impulsive Thermal Loads on Fatigue Behavior of Constant Volume Propulsion Engine Combustor Materials

    National Research Council Canada - National Science Library

    Zhu, Dongming

    2004-01-01

    .... In this study, a simulated engine test rig has been established to evaluate thermal fatigue behavior of a candidate engine combustor material, Haynes 188, under superimposed CO2 laser surface impulsive thermal loads (30 to 100 Hz...

  20. Thermal Performance of a Scramjet Combustor Operating at Mach 5.6 Flight Conditions

    National Research Council Canada - National Science Library

    Stouffer, Scott

    1997-01-01

    .... The objective of the thermal loads testing was to map the thermal and mechanical loads, including heat transfer, dynamic and static pressures, and skin friction in a scramjet combustor during direct...

  1. The Performance of Hydrocarbon Fuels with H2O2 in a Uni-element Combustor

    National Research Council Canada - National Science Library

    Muss, Jeffrey

    2003-01-01

    .... The combustor used decomposed 90% hydrogen peroxide as the oxidizer. The water-cooled combustion chamber included significant fuel film cooling, with the overall mixture ratio (MR) ranging from 3.75 to 7.4...

  2. Investigation of soot and carbon formation in small gas turbine combustors

    Science.gov (United States)

    Rosfjord, T. J.

    1982-01-01

    An investigation of hardware configurations which attempt to minimize carbon and soot-production without sacrificing performance in small gas turbine combustors was conducted. Four fuel injectors, employing either airblast atomization, pressure atomization, or fuel vaporization techniques were combined with nozzle air swirlers and injector sheaths. Eight configurations were screened at sea-level takeoff and idle test conditions. Selected configurations were focused upon in an attempt to quantify the influence of combustor pressure, inlet temperature, primary zone operation, and combustor loading on soot and carbon formation. Cycle tests were also performed. It was found that smoke emission levels depended on the combustor fluid mechanics, the atomization quality of the injector and the fuel hydrogen content.

  3. Rocket Combustor Validation Data for Advanced Combustion Models, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The pace and cost of developing an engine system for future explorations is strongly influenced by the inadequacies of design tools and the supporting databases. The...

  4. MAID : An effect size based model for microarray data integration across laboratories and platforms

    Directory of Open Access Journals (Sweden)

    Edwards Aled M

    2008-07-01

    Full Text Available Abstract Background Gene expression profiling has the potential to unravel molecular mechanisms behind gene regulation and identify gene targets for therapeutic interventions. As microarray technology matures, the number of microarray studies has increased, resulting in many different datasets available for any given disease. The increase in sensitivity and reliability of measurements of gene expression changes can be improved through a systematic integration of different microarray datasets that address the same or similar biological questions. Results Traditional effect size models can not be used to integrate array data that directly compare treatment to control samples expressed as log ratios of gene expressions. Here we extend the traditional effect size model to integrate as many array datasets as possible. The extended effect size model (MAID can integrate any array datatype generated with either single or two channel arrays using either direct or indirect designs across different laboratories and platforms. The model uses two standardized indices, the standard effect size score for experiments with two groups of data, and a new standardized index that measures the difference in gene expression between treatment and control groups for one sample data with replicate arrays. The statistical significance of treatment effect across studies for each gene is determined by appropriate permutation methods depending on the type of data integrated. We apply our method to three different expression datasets from two different laboratories generated using three different array platforms and two different experimental designs. Our results indicate that the proposed integration model produces an increase in statistical power for identifying differentially expressed genes when integrating data across experiments and when compared to other integration models. We also show that genes found to be significant using our data integration method are of direct

  5. Controlled laboratory experiments and modeling of vegetative filter strips with shallow water tables

    Science.gov (United States)

    Fox, Garey A.; Muñoz-Carpena, Rafael; Purvis, Rebecca A.

    2018-01-01

    Natural or planted vegetation at the edge of fields or adjacent to streams, also known as vegetative filter strips (VFS), are commonly used as an environmental mitigation practice for runoff pollution and agrochemical spray drift. The VFS position in lowlands near water bodies often implies the presence of a seasonal shallow water table (WT). In spite of its potential importance, there is limited experimental work that systematically studies the effect of shallow WTs on VFS efficacy. Previous research recently coupled a new physically based algorithm describing infiltration into soils bounded by a water table into the VFS numerical overland flow and transport model, VFSMOD, to simulate VFS dynamics under shallow WT conditions. In this study, we tested the performance of the model against laboratory mesoscale data under controlled conditions. A laboratory soil box (1.0 m wide, 2.0 m long, and 0.7 m deep) was used to simulate a VFS and quantify the influence of shallow WTs on runoff. Experiments included planted Bermuda grass on repacked silt loam and sandy loam soils. A series of experiments were performed including a free drainage case (no WT) and a static shallow water table (0.3-0.4 m below ground surface). For each soil type, this research first calibrated VFSMOD to the observed outflow hydrograph for the free drainage experiments to parameterize the soil hydraulic and vegetation parameters, and then evaluated the model based on outflow hydrographs for the shallow WT experiments. This research used several statistical metrics and a new approach based on hypothesis testing of the Nash-Sutcliffe model efficiency coefficient (NSE) to evaluate model performance. The new VFSMOD routines successfully simulated the outflow hydrographs under both free drainage and shallow WT conditions. Statistical metrics considered the model performance valid with greater than 99.5% probability across all scenarios. This research also simulated the shallow water table experiments with

  6. Electrical triggering of earthquakes: results of laboratory experiments at spring-block models

    Science.gov (United States)

    Novikov, Victor A.; Okunev, Vladimir I.; Klyuchkin, Vadim N.; Liu, Jing; Ruzhin, Yuri Ya.; Shen, Xuhui

    2017-08-01

    Recently published results of field and laboratory experiments on the seismic/acoustic response to injection of direct current (DC) pulses into the Earth crust or stressed rock samples raised a question on a possibility of electrical earthquake triggering. A physical mechanism of the considered phenomenon is not clear yet in view of the very low current density (10-7-10-8 A/m2) generated by the pulsed power systems at the epicenter depth (5-10 km) of local earthquakes occurred just after the current injection. The paper describes results of laboratory "earthquake" triggering by DC pulses under conditions of a spring-block model simulated the seismogenic fault. It is experimentally shown that the electric triggering of the laboratory "earthquake" (sharp slip of a movable block of the spring-block system) is possible only within a range of subcritical state of the system, when the shear stress between the movable and fixed blocks obtains 0.98-0.99 of its critical value. The threshold of electric triggering action is about 20 A/m2 that is 7-8 orders of magnitude higher than estimated electric current density for Bishkek test site (Northern Tien Shan, Kirghizia) where the seismic response to the man-made electric action was observed. In this connection, the electric triggering phenomena may be explained by contraction of electric current in the narrow conductive areas of the faults and the corresponding increase in current density or by involving the secondary triggering mechanisms like electromagnetic stimulation of conductive fluid migration into the fault area resulted in decrease in the fault strength properties.

  7. Numerical Simulations of Two-Phase Reacting Flow in a Single-Element Lean Direct Injection (LDI) Combustor Using NCC

    Science.gov (United States)

    Liu, Nan-Suey; Shih, Tsan-Hsing; Wey, C. Thomas

    2011-01-01

    A series of numerical simulations of Jet-A spray reacting flow in a single-element lean direct injection (LDI) combustor have been conducted by using the National Combustion Code (NCC). The simulations have been carried out using the time filtered Navier-Stokes (TFNS) approach ranging from the steady Reynolds-averaged Navier-Stokes (RANS), unsteady RANS (URANS), to the dynamic flow structure simulation (DFS). The sub-grid model employed for turbulent mixing and combustion includes the well-mixed model, the linear eddy mixing (LEM) model, and the filtered mass density function (FDF/PDF) model. The starting condition of the injected liquid spray is specified via empirical droplet size correlation, and a five-species single-step global reduced mechanism is employed for fuel chemistry. All the calculations use the same grid whose resolution is of the RANS type. Comparisons of results from various models are presented.

  8. Material model for shear of the buffer - evaluation of laboratory test results

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Dueck, Ann; Johannesson, Lars-Erik

    2010-12-01

    The report describes the material model of bentonite used for analysing a rock shear through a deposition hole. The old model used in SR-Can has been considerably changed. The new reference model that has been developed for SR-Site is described and motivated. The relevant properties of the buffer that affect the response to a rock shear are (in addition to the bentonite type) the density (which yields a swelling pressure), the shear strength, the stiffness before the maximum shear stress is reached and the shear rate, which also affects the shear strength. Since the shear caused by an earthquake is very fast and the hydraulic conductivity of the bentonite is very low there is no possibility for the pore water in the water saturated bentonite to be redistributed. Since the compressibility of water and particles are negligible, the bentonite can be modelled as a solid material that cannot change volume but only exhibit shear deformations. A proper and simple model that behaves accordingly is a model with von Mises' stress modelled as a function of the strain (stress-strain model). The model is elastic-plastic with an E-modulus that determines the behaviour until the material starts yielding whereupon the plastic strain is modelled as a function of von Mises' stress and added to the elastic strain. Included in the model is also a strain rate dependency of the stress-strain relation, which ranges between the strain rates 10 -6 1/s 3 1/s. The reference material model is derived from a large number of laboratory tests made on different bentonites at different strain rates, densities and with different techniques. Since it cannot be excluded that the exchangeable cat-ions in the Na-bentonite MX-80 is exchanged to calcium-ions the Ca-bentonite Deponit CaN is proposed to be used as reference material. The overall conclusion is that a relevant and probably also slightly conservative material model of Ca-converted MX-80 is derived, presented and well motivated

  9. Material model for shear of the buffer - evaluation of laboratory test results

    Energy Technology Data Exchange (ETDEWEB)

    Boergesson, Lennart; Dueck, Ann; Johannesson, Lars-Erik (Clay Technology AB (Sweden))

    2010-12-15

    The report describes the material model of bentonite used for analysing a rock shear through a deposition hole. The old model used in SR-Can has been considerably changed. The new reference model that has been developed for SR-Site is described and motivated. The relevant properties of the buffer that affect the response to a rock shear are (in addition to the bentonite type) the density (which yields a swelling pressure), the shear strength, the stiffness before the maximum shear stress is reached and the shear rate, which also affects the shear strength. Since the shear caused by an earthquake is very fast and the hydraulic conductivity of the bentonite is very low there is no possibility for the pore water in the water saturated bentonite to be redistributed. Since the compressibility of water and particles are negligible, the bentonite can be modelled as a solid material that cannot change volume but only exhibit shear deformations. A proper and simple model that behaves accordingly is a model with von Mises' stress modelled as a function of the strain (stress-strain model). The model is elastic-plastic with an E-modulus that determines the behaviour until the material starts yielding whereupon the plastic strain is modelled as a function of von Mises' stress and added to the elastic strain. Included in the model is also a strain rate dependency of the stress-strain relation, which ranges between the strain rates 10-6 1/s < v < 103 1/s. The reference material model is derived from a large number of laboratory tests made on different bentonites at different strain rates, densities and with different techniques. Since it cannot be excluded that the exchangeable cat-ions in the Na-bentonite MX-80 is exchanged to calcium-ions the Ca-bentonite Deponit CaN is proposed to be used as reference material. The overall conclusion is that a relevant and probably also slightly conservative material model of Ca-converted MX-80 is derived, presented and well

  10. Characterization of Centrifugally-Loaded Flame Migration for Ultra-Compact Combustors

    Science.gov (United States)

    2011-10-01

    with the Alstom GT24 and GT26 commercial engines [35]. Hiddeman used the term ”sequential combustion” rather than ITB and demonstrated that the benefit...of the new Alstom engines was increased power gen- eration for similar turbine temperatures via distribution of the combustion process between the main...combustor and second combustor, located in between the HPT and LPT [35]. While the Alstom engines demonstrate the ITB cycle benefits, realization of

  11. Coupled numerical modeling of gas hydrates bearing sediments from laboratory to field-scale conditions

    Science.gov (United States)

    Sanchez, M. J.; Santamarina, C.; Gai, X., Sr.; Teymouri, M., Sr.

    2017-12-01

    Stability and behavior of Hydrate Bearing Sediments (HBS) are characterized by the metastable character of the gas hydrate structure which strongly depends on thermo-hydro-chemo-mechanical (THCM) actions. Hydrate formation, dissociation and methane production from hydrate bearing sediments are coupled THCM processes that involve, amongst other, exothermic formation and endothermic dissociation of hydrate and ice phases, mixed fluid flow and large changes in fluid pressure. The analysis of available data from past field and laboratory experiments, and the optimization of future field production studies require a formal and robust numerical framework able to capture the very complex behavior of this type of soil. A comprehensive fully coupled THCM formulation has been developed and implemented into a finite element code to tackle problems involving gas hydrates sediments. Special attention is paid to the geomechanical behavior of HBS, and particularly to their response upon hydrate dissociation under loading. The numerical framework has been validated against recent experiments conducted under controlled conditions in the laboratory that challenge the proposed approach and highlight the complex interaction among THCM processes in HBS. The performance of the models in these case studies is highly satisfactory. Finally, the numerical code is applied to analyze the behavior of gas hydrate soils under field-scale conditions exploring different features of material behavior under possible reservoir conditions.

  12. Instructional designing the STEM education model for fostering creative thinking abilities in physics laboratory environment classes

    Science.gov (United States)

    Chanthala, Chumpon; Santiboon, Toansakul; Ponkham, Kamon

    2018-01-01

    To investigate the effects of students' activity-based on learning approaching management through the STEM Education Instructional Model for fostering their creative thinking abilities of their learning achievements in physics laboratory classroom environments with the sample size consisted of 48 students at the 10th grade level in two classes in Mahasarakham University Demonstration School(Secondary Division) in Thailand. Students' creative thinking abilities were assessed with the with the 24-item GuilfordCreative Thinking Questionnaire (GCTQ). Students' perceptions of their physics classroom learning environments were obtained using the 35-item Physics Laboratory Environment Inventory (PLEI). Associations between students' learning achievements of their post-test assessment indicated that 26% of the coefficient predictive value (R2) of the variance in students' creative thinking abilities was attributable to their perceptions for the GCTQ. Students' learning outcomes of their post-test assessment, the R2value indicated that 35% of the variances for the PLEI, the R2value indicated that 63% of the variances for their creative thinking abilities were attributable to theiraffecting the activity-based on learning for fostering their creative thinking are provided.

  13. Organizational Learning Supported by Reference Architecture Models: Industry 4.0 Laboratory Study

    Directory of Open Access Journals (Sweden)

    Marco Nardello

    2017-10-01

    Full Text Available The wave of the fourth industrial revolution (Industry 4.0 is bringing a new vision of the manufacturing industry. In manufacturing, one of the buzzwords of the moment is "Smart production". Smart production involves manufacturing equipment with many sensors that can generate and transmit large amounts of data. These data and information from manufacturing operations are however not shared in the organization. Therefore the organization is not using them to learn and improve their operations. To address this problem, the authors implemented in an Industry 4.0 laboratory an instance of an emerging technical standard specific for the manufacturing industry. Global manufacturing experts consider the Reference Architecture Model Industry 4.0 (RAMI4.0 as one of the corner stones for the implementation of Industry 4.0. The instantiation contributed to organizational learning in the laboratory by collecting and sharing up-to-date information concerning manufacturing equipment. This article discusses and generalizes the experience and outlines future research directions.

  14. Laboratory Experiments on Steady State Seepage-Induced Landslides Using Slope Models and Sensors

    Directory of Open Access Journals (Sweden)

    Sandra G. Catane

    2011-06-01

    Full Text Available A thorough understanding of the failure initiation process is crucial in the development of physicallybased early warning system for landslides and slope failures. Laboratory-scale slope models were constructed and subjected to instability through simulated groundwater infiltration. This is done by progressively increasing the water level in the upslope tank and allowing water to infiltrate laterally towards the toe of the slope. Physical changes in the slope models were recorded by tilt sensors and video cameras. When the model slope was destabilized, the chronology of events occurred in the following sequence: (1 bulging at the toe, (2 seepage at the toe, (3 initial failure of soil mass, (4 piping, (5 retrogressive failure, (6 formation of tension cracks and (7 major failure of soil mass. Tension cracks, piping and eventual failure are manifestations of differential settlements due to variations in void ratio. Finite element analysis indicates that instability and subsequent failures in the model slope were induced primarily by high hydraulic gradients in the toe area. Seepage, initial deformation and subsequent failures were manifested in the toe area prior to failure, providing a maximum of 36 min lead time. Similar lead times are expected in slopes of the same material as shown in many case studies of dam failure. The potential of having a longer lead time is high for natural slopes made of materials with higher shear strength thus evacuation is possible. The tilt sensors were able to detect the initial changes before visual changes manifested, indicating the importance of instrumental monitoring.

  15. Spectrodirectional Investigation of a Geometric-Optical Canopy Reflectance Model by Laboratory Simulation

    Science.gov (United States)

    Stanford, Adam Christopher

    Canopy reflectance models (CRMs) can accurately estimate vegetation canopy biophysical-structural information such as Leaf Area Index (LAI) inexpensively using satellite imagery. The strict physical basis which geometric-optical CRMs employ to mathematically link canopy bidirectional reflectance and structure allows for the tangible replication of a CRM's geometric abstraction of a canopy in the laboratory, enabling robust CRM validation studies. To this end, the ULGS-2 goniometer was used to obtain multiangle, hyperspectral (Spectrodirectional) measurements of a specially-designed tangible physical model forest, developed based upon the Geometric-Optical Mutual Shadowing (GOMS) CRM, at three different canopy cover densities. GOMS forward-modelled reflectance values had high levels of agreement with ULGS-2 measurements, with obtained reflectance RMSE values ranging from 0.03% to 0.1%. Canopy structure modelled via GOMS Multiple-Forward-Mode (MFM) inversion had varying levels of success. The methods developed in this thesis can potentially be extended to more complex CRMs through the implementation of 3D printing.

  16. VESL: The Virtual Earth Sheet Laboratory for Ice Sheet Modeling and Visualization

    Science.gov (United States)

    Cheng, D. L. C.; Larour, E. Y.; Quinn, J. D.; Halkides, D. J.

    2017-12-01

    We present the Virtual Earth System Laboratory (VESL), a scientific modeling and visualization tool delivered through an integrated web portal. This allows for the dissemination of data, simulation of physical processes, and promotion of climate literacy. The current iteration leverages NASA's Ice Sheet System Model (ISSM), a state-of-the-art polar ice sheet dynamics model developed at the Jet Propulsion Lab and UC Irvine. We utilize the Emscripten source-to-source compiler to convert the C/C++ ISSM engine core to JavaScript, and bundled pre/post-processing JS scripts to be compatible with the existing ISSM Python/Matlab API. Researchers using VESL will be able to effectively present their work for public dissemination with little-to-no additional post-processing. Moreover, the portal allows for real time visualization and editing of models, cloud based computational simulation, and downloads of relevant data. This allows for faster publication in peer-reviewed journals and adaption of results for educational applications. Through application of this concept to multiple aspects of the Earth System, VESL is able to broaden data applications in the geosciences and beyond. At this stage, we still seek feedback from the greater scientific and public outreach communities regarding the ease of use and feature set of VESL. As we plan its expansion, we aim to achieve more rapid communication and presentation of scientific results.

  17. Reconciling laboratory and observational models of mantle rheology in geodynamic modelling

    Science.gov (United States)

    King, Scott D.

    2016-10-01

    Experimental and geophysical observations constraining mantle rheology are reviewed with an emphasis on their impact on mantle geodynamic modelling. For olivine, the most studied and best-constrained mantle mineral, the tradeoffs associated with the uncertainties in the activation energy, activation volume, grain-size and water content allow the construction of upper mantle rheology models ranging from nearly uniform with depth to linearly increasing from the base of the lithosphere to the top of the transition zone. Radial rheology models derived from geophysical observations allow for either a weak upper mantle or a weak transition zone. Experimental constraints show that wadsleyite and ringwoodite are stronger than olivine at the top of the transition zone; however the uncertainty in the concentration of water in the transition zone precludes ruling out a weak transition zone. Both observational and experimental constraints allow for strong or weak slabs and the most promising constraints on slab rheology may come from comparing inferred slab geometry from seismic tomography with systematic studies of slab morphology from dynamic models. Experimental constraints on perovskite and ferropericlase strength are consistent with general feature of rheology models derived from geophysical observations and suggest that the increase in viscosity through the top of the upper mantle could be due to the increase in the strength of ferropericlase from 20-65 GPa. The decrease in viscosity in the bottom half of the lower mantle could be the result of approaching the melting temperature of perovskite. Both lines of research are consistent with a high-viscosity lithosphere, a low viscosity either in the upper mantle or transition zone, and high viscosity in the lower mantle, increasing through the upper half of the lower mantle and decreasing in the bottom half of the lower mantle, with a low viscosity above the core. Significant regions of the mantle, including high

  18. Space Weather Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Space Weather Computational Laboratory is a Unix and PC based modeling and simulation facility devoted to research analysis of naturally occurring electrically...

  19. Presentation on the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC): A Working Model and Progress Report

    Science.gov (United States)

    Glesener, G. B.; Vican, L.

    2015-12-01

    Physical analog models and demonstrations can be effective educational tools for helping instructors teach abstract concepts in the Earth, planetary, and space sciences. Reducing the learning challenges for students using physical analog models and demonstrations, however, can often increase instructors' workload and budget because the cost and time needed to produce and maintain such curriculum materials is substantial. First, this presentation describes a working model for the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC) to support instructors' use of physical analog models and demonstrations in the science classroom. The working model is based on a combination of instructional resource models developed by the Association of College & Research Libraries and by the Physics Instructional Resource Association. The MEDL-CMC aims to make the curriculum materials available for all science courses and outreach programs within the institution where the MEDL-CMC resides. The sustainability and value of the MEDL-CMC comes from its ability to provide and maintain a variety of physical analog models and demonstrations in a wide range of science disciplines. Second, the presentation then reports on the development, progress, and future of the MEDL-CMC at the University of California Los Angeles (UCLA). Development of the UCLA MEDL-CMC was funded by a grant from UCLA's Office of Instructional Development and is supported by the Department of Earth, Planetary, and Space Sciences. Other UCLA science departments have recently shown interest in the UCLA MEDL-CMC services, and therefore, preparations are currently underway to increase our capacity for providing interdepartmental service. The presentation concludes with recommendations and suggestions for other institutions that wish to start their own MEDL-CMC in order to increase educational effectiveness and decrease instructor workload. We welcome an interuniversity collaboration to

  20. Laboratory infrastructure driven key performance indicator development using the smart grid architecture model

    DEFF Research Database (Denmark)

    Syed, Mazheruddin H.; Guillo-Sansano, Efren; Blair, Steven M.

    2017-01-01

    This study presents a methodology for collaboratively designing laboratory experiments and developing key performance indicators for the testing and validation of novel power system control architectures in multiple laboratory environments. The contribution makes use of the smart grid architecture...

  1. Can mouthguards prevent mandibular bone fractures and concussions? A laboratory study with an artificial skull model.

    Science.gov (United States)

    Takeda, Tomotaka; Ishigami, Keiichi; Hoshina, Sanae; Ogawa, Toru; Handa, Jun; Nakajima, Kazunori; Shimada, Atsushi; Nakajima, Tsuneya; Regner, Connell Wayne

    2005-06-01

    Some sports' accidents are responsible for inflicting traumatic brain injuries and mandibular bone fractures when impacts occur to the chin. It is often thought that mouth guards can prevent many of these injuries. However, such assertions may be insufficient without adequate research. It is therefore necessary to establish a systematic method of investigation to solve this problem. In the present laboratory study, tests were performed using pendulum impact equipment and an artificial skull model connected to strain gages and accelerometers to simulate and measure the surface distortions related to bone deformation or fractures and the acceleration of the head related to concussions. As impacts, direct blows to the mandibular undersurface were applied. As a result, wearing a mouth guard decreased (P fractures and concussions. However, further well-designed and exhaustive studies are vital to show that mouth guards reduce the incidence of concussions and mandibular bone fractures.

  2. Laboratory modelling of the transfer processes between the ocean and atmosphere in the boundary layers

    Directory of Open Access Journals (Sweden)

    Sergeev Daniil

    2017-01-01

    Full Text Available The processes of momentum and heat transfer between ocean and atmosphere in the boundary layer were investigated within laboratory modeling for a wide range of wind speed and surface wave including hurricane conditions. Experiments were carried out on the Wind-Wave Flume of the Large Thermostratified Tank of IAP RAS. A special net located under the surface at different depths allows to vary parameters of surface waves independently on wind parameters. Theory of self-similarity of air flow parameters in the flume was used to calculate values aerodynamic and heat transfer coefficients from the measured velocity and temperature profiles by Pito and hotfilm gauges respectively. Simultaneous measurements of surface elevation with system wire allow to obtain spectra and integral parameters of waves. It was demonstrated that in contrast to the drag coefficient, heat transfer coefficient is virtually independent of wind speed and wave parameters to the moment of the beginning of spray generation and then increases rapidly.

  3. Thermal behavior of laboratory models of honeycomb-covered solar ponds

    Science.gov (United States)

    Lin, E. I. H.

    1983-01-01

    Laboratory experiments were conducted to provide insight into the technical feasibility of honeycomb-covered solar ponds. Cooling tests using honeycomb panels of various materials and geometries showed that a 5.7-cm-thick one-tier panel insulated as effectively as a 10-cm fiberglass slab. Heating tests demonstrated that a model pond covered with a polycarbonate panel boiled upon 16 hours of continuous exposure to a 150-W spotlight. Analysis of the experimental data indicates positively that honeycomb-covered solar ponds can be expected to perform satisfactorily, and that larger-scale outdoor tests should be conducted to provide a more realistic assessment and a more refined performance estimate.

  4. Use of a miniature laboratory fresh cheese model for investigating antimicrobial activities.

    Science.gov (United States)

    Van Tassell, M L; Ibarra-Sánchez, L A; Takhar, S R; Amaya-Llano, S L; Miller, M J

    2015-12-01

    Hispanic-style fresh cheeses, such as queso fresco, have relatively low salt content, high water activity, and near neutral pH, which predisposes them to growth of Listeria monocytogenes. Biosafety constraints limit the incorporation of L. monocytogenes into cheeses manufactured via traditional methods in challenge studies, so few have focused on in situ testing of novel antimicrobials in fresh cheeses. We have developed a modular, miniaturized laboratory-scale queso fresco model for testing the incorporation of novel antilisterials. We have demonstrated the assessment of the antilisterials nisin and ferulic acid, alone and in combination, at various levels. Our results support the inhibitory effects of ferulic acid in cheese, against both L. monocytogenes and its common surrogate Listeria innocua, and we provide preliminary evaluation of its consumer acceptability. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  5. Development of a laboratory model to assess fear and anxiety in cats.

    Science.gov (United States)

    de Rivera, Christina; Ley, Jacqui; Milgram, Bill; Landsberg, Gary

    2017-06-01

    Objectives The objectives of this study were: (1) to develop a laboratory-based model to assess fear and anxiety in cats using the feline open-field test (OFT) and the feline human interaction test (HIT); and (2) to validate the model using diazepam, a known anxiolytic. Methods Laboratory-housed cats (n = 41) were first classified as fearful, mildly fearful or non-fearful by a technician familiar with the cats and also by veterinary behaviorists (GL, JL), by assessing the cats' behavior in their home rooms. In experiment 1, each cat's behavior was assessed in an OFT and an HIT. In experiment 2, after administration of the anxiolytic diazepam, a subset of the cats was re-tested. Results In experiment 1, the OFT revealed significant group effects on two measures: duration of inactivity, and vocalization. Fearful animals had significantly longer periods of inactivity than non-fearful animals. Non-fearful and mildly fearful cats vocalized more frequently than fearful cats. In the HIT, fearful cats travelled less than non-fearful and mildly fearful cats. Fearful and mildly fearful animals had significantly longer durations of inactivity, and non-fearful and mildly fearful cats had a significantly higher frequency of vocalization compared with fearful cats. In experiment 2, in the OFT, treatment with diazepam caused an increase in distance travelled, shorter durations of inactivity, and more frequent inactivity and vocalization. In the HIT, diazepam increased distance travelled and decreased duration of inactivity. Fearful cats spent significantly less time near the human compared with non-fearful cats, and this persisted under diazepam. Conclusions and relevance The feline OFT and feline HIT can be used jointly to assess the effects of medications or other therapies on fear and anxiety in the domestic cat.

  6. The Use of an Ultra-Compact Combustor as an Inter-Turbine Burner for Improved Engine Performance

    Science.gov (United States)

    2014-03-27

    Alstom , formally known as ABB Power Generation, developed a line of SCgas turbines for the power generation industry [12]. The Alstom GT24 and GT26...consist of a primary combustor a turbine and a reheat combustor, with the aim of achieving high efficiency while delivering low emissions. Alstom has been...utilizing the SC concepts since the 1940’s using diffusion type combustors. In 1995 Alstom developed their modern line SC gas turbines shown in Figure

  7. Establishing a laboratory model of dental unit waterlines bacterial biofilms using a CDC biofilm reactor.

    Science.gov (United States)

    Yoon, Hye Young; Lee, Si Young

    2017-11-01

    In this study, a laboratory model to reproduce dental unit waterline (DUWL) biofilms was developed using a CDC biofilm reactor (CBR). Bacteria obtained from DUWLs were filtered and cultured in Reasoner's 2A (R2A) for 10 days, and were subsequently stored at -70°C. This stock was cultivated on R2A in batch mode. After culturing for five days, the bacteria were inoculated into the CBR. Biofilms were grown on polyurethane tubing for four days. Biofilm accumulation and thickness was 1.3 × 10 5  CFU cm -2 and 10-14 μm respectively, after four days. Bacteria in the biofilms included cocci and rods of short and medium lengths. In addition, 38 bacterial genera were detected in biofilms. In this study, the suitability and reproducibility of the CBR model for DUWL biofilm formation were demonstrated. The model provides a foundation for the development of bacterial control methods for DUWLs.

  8. Comprehensive Interpretation of the Laboratory Experiments Results to Construct Model of the Polish Shale Gas Rocks

    Science.gov (United States)

    Jarzyna, Jadwiga A.; Krakowska, Paulina I.; Puskarczyk, Edyta; Wawrzyniak-Guz, Kamila; Zych, Marcin

    2018-03-01

    More than 70 rock samples from so-called sweet spots, i.e. the Ordovician Sa Formation and Silurian Ja Member of Pa Formation from the Baltic Basin (North Poland) were examined in the laboratory to determine bulk and grain density, total and effective/dynamic porosity, absolute permeability, pore diameters size, total surface area, and natural radioactivity. Results of the pyrolysis, i.e., TOC (Total Organic Carbon) together with S1 and S2 - parameters used to determine the hydrocarbon generation potential of rocks, were also considered. Elemental composition from chemical analyses and mineral composition from XRD measurements were also included. SCAL analysis, NMR experiments, Pressure Decay Permeability measurements together with water immersion porosimetry and adsorption/ desorption of nitrogen vapors method were carried out along with the comprehensive interpretation of the outcomes. Simple and multiple linear statistical regressions were used to recognize mutual relationships between parameters. Observed correlations and in some cases big dispersion of data and discrepancies in the property values obtained from different methods were the basis for building shale gas rock model for well logging interpretation. The model was verified by the result of the Monte Carlo modelling of spectral neutron-gamma log response in comparison with GEM log results.

  9. Gelatins as rock analog in laboratory models: a rheological study and preliminary applications

    Science.gov (United States)

    Corbi, F.; di Giuseppe, E.; Funiciello, F.; Ranalli, G.; Faccenna, C.

    2009-12-01

    A laboratory model is a simplified scaled representation of nature. Thereby, according to ‘similarity criteria’, both rheological and physical parameters involved in the modeling must be properly scaled to natural conditions. In this work we systematically investigated the rheological and physical properties of a wide range of gelatins as functions of their temperature, composition, concentration, ageing and strain rate, in both gel- (i.e. solid) and sol-state (i.e. solution). Our results show that the complex mechanical behavior of gelatins reproduces gradually the full range of rheological behavior from purely elastic to visco-elasto-brittle to purely viscous (nonlinear) rheology going from the gel- to the sol-state. The handiness of the manipulation of the gelatins’ microstructure by calibrating the setting parameters and their resulting rheological variability appear promising for the potential use of these analog materials to simulate crustal and lithospheric rheological behavior. In particular, we found that pig skin 2.5 wt.% at 10 °C has the required rheological properties for a suitable experimental set-up to model crustal deformations.

  10. VESL: The Virtual Earth Sheet Laboratory for Ice Sheet Modeling and Visualization

    Science.gov (United States)

    Cheng, D. L. C.; Larour, E. Y.; Quinn, J. D.; Halkides, D. J.

    2016-12-01

    We introduce the Virtual Earth System Laboratory (VESL), a scientific modeling and visualization tool delivered through an integrated web portal for dissemination of data, simulation of physical processes, and promotion of climate literacy. The current prototype leverages NASA's Ice Sheet System Model (ISSM), a state-of-the-art polar ice sheet dynamics model developed at the Jet Propulsion Lab and UC Irvine. We utilize the Emscripten source-to-source compiler to convert the C/C++ ISSM engine core to JavaScript, and bundled pre/post-processing JS scripts to be compatible with the existing ISSM Python/Matlab API. Researchers using VESL will be able to effectively present their work for public dissemination with little-to-no additional post-processing. This will allow for faster publication in peer-reviewed journals and adaption of results for educational applications. Through future application of this concept to multiple aspects of the Earth System, VESL has the potential to broaden data applications in the geosciences and beyond. At this stage, we seek feedback from the greater scientific and public outreach communities regarding the ease of use and feature set of VESL, as we plan its expansion, and aim to achieve more rapid communication and presentation of scientific results.

  11. Laboratory modelling of the physico-chemical processes in the cosmic gas-dust clouds

    International Nuclear Information System (INIS)

    Bakulina, I.N.; Blashenkov, N.M.; Varshalovich, D.A.; Lavrent'ev, G.Ya.; Shustrov, B.N.

    1980-01-01

    The preliminary results of an experiment on the complex laboratory modelling of the physico-chemical processes proceeding in the interstellar gas clouds are presented. The purpose of the modelling is an analysis of the molecule formation and dissociation processes kinetics. The basic component of the modelling system is 10 cm diameter spherical container with cooled walls (the dust particles surface analogue). The high frequency discharger (the discharge region - the H 2 zone analogue) is placed in the central part of the container. The container contains the mixture of simple gases: 10 -1 Tor of H 2 and He, 10 -2 Tor of CO, O 2 and N 2 and 0.5x10 -2 Tor of H 2 S (an analogue of the H 1 zone). The reactions are induced by the electrodeless high-frequency discharge (f=20 MHz) with the discharge power of 0.1-1 W. The resulting mixture has been analyzed by the high-resolution magnetic resonance mass spectrometer. (M/ΔM=2x10 4 ) with an electron impact source. It is shown that, in the reactions of the formation of many on the interstellar molecules, the on the cold dust surface reactions rather than the gas-phase reactions may play the dominant role

  12. Effects of injection pressure variation on mixing in a cold supersonic combustor with kerosene fuel

    Science.gov (United States)

    Liu, Wei-Lai; Zhu, Lin; Qi, Yin-Yin; Ge, Jia-Ru; Luo, Feng; Zou, Hao-Ran; Wei, Min; Jen, Tien-Chien

    2017-10-01

    Spray jet in cold kerosene-fueled supersonic flow has been characterized under different injection pressures to assess the effects of the pressure variation on the mixing between incident shock wave and transverse cavity injection. Based on the real scramjet combustor, a detailed computational fluid dynamics model is developed. The injection pressures are specified as 0.5, 1.0, 2.0, 3.0 and 4.0 MPa, respectively, with the other constant operation parameters (such as the injection diameter, angle and velocity). A three dimensional Couple Level Set & Volume of Fluids approach incorporating an improved Kelvin-Helmholtz & Rayleigh-Taylor model is used to investigate the interaction between kerosene and supersonic air. The numerical simulations primarily concentrate on penetration depth, span expansion area, angle of shock wave and sauter mean diameter distribution of the kerosene droplets with/without evaporation. Validation has been implemented by comparing the calculated against the measured in literature with good qualitative agreement. Results show that the penetration depth, span-wise angle and expansion area of the transverse cavity jet are all increased with the injection pressure. However, when the injection pressure is further increased, the value in either penetration depth or expansion area increases appreciably. This study demonstrates the feasibility and effectiveness of the combination of Couple Level Set & Volume of Fluids approach and an improved Kelvin-Helmholtz & Rayleigh-Taylor model, in turn providing insights into scramjet design improvement.

  13. NONEQUILIBRIUM SULFUR CAPTURE AND RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Bert Zauderer

    1999-03-15

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. They are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, slag must be rapidly drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to perform a series of tests to determine the factors that control the retention of the sulfur in the slag. 36 days of testing on the combustor were completed prior to the end of this reporting period, 12/31/98. This compares with 16 tests required in the original project plan. Combustor tests in early 1997 with high (37%) ash, Indian coal confirmed that high slag mass flow rates of about 500 lb/hr resulted in retention in the slag of up to 20% of the injected sulfur content mineral matter. To further increase the slag flow rate, rice husks, which contain 20% ash, and rice husk char, which contain 70% ash, were co-fired with coal in the combustor. A series of 13 combustor tests were performed in fourth quarter of 1997 and a further 6 tests were performed in January 1998 and in the summer of 1998. The test objective was to achieve slag flow rates between 500 and 1,000 lb/hr. Due to the very low bulk density of rice husk, compared to pulverized coal, almost the entire test effort focused on developing methods for feeding the rice husks into combustor. In the last test of December 1997, a peak mineral matter, injection rate of 592 lb/hr was briefly achieved by injection of coal, rice husk char, gypsum, and limestone into the combustor. However, no significant sulfur concentration was measured in the slag removed from the combustor. The peak injection rate reached with biomass in the 1997 tests was 310 lb/hr with rice husk, and 584 lb/hr with rice husk char.

  14. Laboratory Modeling of Space experiments on Expulsion of CO2 ions. Application to Global Warming.

    Science.gov (United States)

    Wong, A. Y.

    2007-05-01

    An approach to expel minority species which can contribute to global warming from the upper atmosphere in the Arctic region by the use of HF electromagnetic waves has been proposed [1]. Laboratory plasma experiments have been designed to model various aspects of this concept - from the acquisiton of negative charges by green house gases such as CO2 to their ascent to the upper atmosphere and their acceleration and expulsion along the open magnetic field lines. Laboratory results are presented which confirmed the efficient gyro-resonance acceleration of minority ion species made possible through the space charge cancellation by majority species. The outflow of CO2 ions from the divergent magnetic field of a laboratory plasma device is measured at various background neutral pressures and for different amount of currents along the axial magnetic field. The central idea is to impart perpendicular energy to a selective ion species gyrating around the geomagnetic field at its cyclotron resonance. The wave field is produced by either modulating the auroral electrojet or from the nonlinear interaction between two electron plasma resonances. In the presence of the divergent polar geomagnetic field the accelerated perpendicular ion velocity is converted into an upward motion along open magnetic field lines. The ions thus removed will unlikely find their way back to the lower atmosphere. Negatively charged particles move upward by the fair-weather electric field and by atmospheric convection. When these ions reach above 120 km altitude where the ion gyro frequency is comparable to or greater than the ion- neutral collision frequency, they can be accelerated by EM fields through the gyro resonance interaction. The propagation of these low frequency waves to the upper atmosphere along the earth's magnetic field is permitted by the plasma dispersion relation. Laboratory experiments play an important role in confirming the theoretical prediction that ion cyclotron waves can grow

  15. Fire spread in chaparral – a comparison of laboratory data and model predictions in burning live fuels

    Science.gov (United States)

    David R. Weise; Eunmo Koo; Xiangyang Zhou; Shankar Mahalingam; Frédéric Morandini; Jacques-Henri Balbi

    2016-01-01

    Fire behaviour data from 240 laboratory fires in high-density live chaparral fuel beds were compared with model predictions. Logistic regression was used to develop a model to predict fire spread success in the fuel beds and linear regression was used to predict rate of spread. Predictions from the Rothermel equation and three proposed changes as well as two physically...

  16. Improving of Quality Control and Quality Assurance in 14C and 3H Laboratory; Participation in the IAEA Model Project

    International Nuclear Information System (INIS)

    Obelic, B.

    2001-01-01

    Full text: Users of laboratory's analytical results are increasingly requiring demonstrable proofs of the reliability and credibility of the results using internationally accepted standards, because the economic, ecological, medical and legal decisions based on laboratory results need to be accepted nationally and internationally. Credibility, respect and opportunities of the laboratories are improved when objective evidence on the reliability and quality of the results can be given. This is achieved through inculcation of a quality culture through definition of well-defined procedures and controls and operational checks characteristic of quality assurance and quality control (Q A/QC). IAEA launched in 1999 a two-and-a-half year model project entitled Quality Control and Quality Assurance of Nuclear Analytical Techniques with participation of laboratories using alpha, beta and/or gamma spectrometry from CEE and NIS countries. The project started to introduce and implement QA principles in accordance with the ISO-17025 guide, leading eventually to a level at which the QA system is self-sustainable and might be appropriate for formal accreditation or certification by respective national authorities. Activities within the project consist of semi-annual reports, two training workshops, two inspection visits of the laboratories by IAEA experts and proficiency tests. The following topics were considered: organisation requirements, acceptance criteria and non-conformance management of QC, internal and external method validation, statistical analyses and uncertainty evaluation, standard operation procedures and quality manual documentation. 14 C and 3 H Laboratory of the Rudjer Boskovic Institute has been one of ten laboratories participating in the Project. In the Laboratory all the procedures required in the quality control were included implicitly, while during the Model Project much effort has been devoted to elaboration of explicit documentation. Since the beginning

  17. Laser-shocked energetic materials for laboratory-scale characterization and model validation

    Science.gov (United States)

    Gottfried, Jennifer

    The development of laboratory-scale methods for characterizing the properties of energetic materials, i.e., using only milligram quantities of material, is essential for the development of new types of explosives and propellants for use in military applications. Laser-based excitation methods for initiating or exciting the energetic material offer several advantages for investigating the response of energetic materials to various stimuli: 1) very small quantities of material can be studied prior to scale-up synthesis, 2) no detonation of bulk energetic material is required, eliminating the need for expensive safety precautions, and 3) extensive diagnostics can be incorporated into the experimental setup to provide as much information as possible per shot. In this presentation, progress in our laboratory developing three laser-based methods for characterizing energetic materials will be discussed. Direct excitation of a sample residue using a focused nanosecond laser pulse enables estimation of the performance of the energetic material based on the measured shock wave velocity with a technique called laser-induced air shock from energetic materials (LASEM); recent LASEM results on novel energetic materials will be presented. Impact ignition of energetic materials has also been investigated using laser-driven flyer plates. High-speed schlieren imaging of the flyer plate launch has demonstrated that late-time emission from the impacted energetic material is caused by the reaction of particles ejected off the sample surface with the flyer plate launch products. Finally, the role of a rapid temperature jump (1014 K/s) in the initiation of the explosive cyclotrimethylenetrinitramine (RDX) has been investigated by indirect ultrafast laser heating. Although the temperature jump was insufficient to decompose the RDX, it did induce a temporary electronic excitation of the heated explosive molecules. These results are being used to validate multiscale models in order to

  18. Laboratory-based surveillance in the molecular era: The typened model, a joint data-sharing platform for clinical and public health laboratories

    NARCIS (Netherlands)

    H.G.M. Niesters (Bert); J.W. Rossen (John); H.G.A.M. van der Avoort (Harrie); D. Baas; K. Benschop (Kimberley); E.C.J. Claas (Eric); A. Kroneman; N.M. van Maarseveen (Noortje); S.D. Pas (Suzan); W. van Pelt (Wilfred); J. Rahamat-Langendoen (Janette); R. Schuurman (Rob); H. Vennema (Harry); L. Verhoef; K.C. Wolthers (Katja); M.P.G. Koopmans D.V.M. (Marion)

    2013-01-01

    textabstractLaboratory-based surveillance, one of the pillars of monitoring infectious disease trends, relies on data produced in clinical and/or public health laboratories. Currently, diagnostic laboratories worldwide submit strains or samples to a relatively small number of reference laboratories

  19. Laboratory-based surveillance in the molecular era : the TYPENED model, a joint data-sharing platform for clinical and public health laboratories

    NARCIS (Netherlands)

    Niesters, H G; Rossen, J W; van der Avoort, H; Baas, D; Benschop, K; Claas, E C; Kroneman, A; van Maarseveen, N; Pas, S; van Pelt, W; Rahamat-Langendoen, J C; Schuurman, R; Vennema, H; Verhoef, L; Wolthers, K; Koopmans, Marion

    2013-01-01

    Laboratory-based surveillance, one of the pillars of monitoring infectious disease trends, relies on data produced in clinical and/or public health laboratories. Currently, diagnostic laboratories worldwide submit strains or samples to a relatively small number of reference laboratories for

  20. Laboratory-based surveillance in the molecular era: the TYPENED model, a joint data-sharing platform for clinical and public health laboratories

    NARCIS (Netherlands)

    Niesters, H. G.; Rossen, J. W.; van der Avoort, H.; Baas, D.; Benschop, K.; Claas, E. C.; Kroneman, A.; van Maarseveen, N.; Pas, S.; van Pelt, W.; Rahamat-Langendoen, J. C.; Schuurman, R.; Vennema, H.; Verhoef, L.; Wolthers, K.; Koopmans, M.

    2013-01-01

    Laboratory-based surveillance, one of the pillars of monitoring infectious disease trends, relies on data produced in clinical and/or public health laboratories. Currently, diagnostic laboratories worldwide submit strains or samples to a relatively small number of reference laboratories for

  1. What Can Be Learned From a Laboratory Model of Conceptual Change? Descriptive Findings and Methodological Issues

    Science.gov (United States)

    Ohlsson, Stellan; Cosejo, David G.

    2014-07-01

    The problem of how people process novel and unexpected information— deep learning (Ohlsson in Deep learning: how the mind overrides experience. Cambridge University Press, New York, 2011)—is central to several fields of research, including creativity, belief revision, and conceptual change. Researchers have not converged on a single theory for conceptual change, nor has any one theory been decisively falsified. One contributing reason is the difficulty of collecting informative data in this field. We propose that the commonly used methodologies of historical analysis, classroom interventions, and developmental studies, although indispensible, can be supplemented with studies of laboratory models of conceptual change. We introduce re- categorization, an experimental paradigm in which learners transition from one definition of a categorical concept to another, incompatible definition of the same concept, a simple form of conceptual change. We describe a re-categorization experiment, report some descriptive findings pertaining to the effects of category complexity, the temporal unfolding of learning, and the nature of the learner's final knowledge state. We end with a brief discussion of ways in which the re-categorization model can be improved.

  2. Practical utilization of modeling and simulation in laboratory process waste assessments

    International Nuclear Information System (INIS)

    Lyttle, T.W.; Smith, D.M.; Weinrach, J.B.; Burns, M.L.

    1993-01-01

    At Los Alamos National Laboratory (LANL), facility waste streams tend to be small but highly diverse. Initial characterization of such waste streams is difficult in part due to a lack of tools to assist the waste generators in completing such assessments. A methodology has been developed at LANL to allow process knowledgeable field personnel to develop baseline waste generation assessments and to evaluate potential waste minimization technology. This process waste assessment (PWA) system is an application constructed within the process modeling system. The Process Modeling System (PMS) is an object-oriented, mass balance-based, discrete-event simulation using the common LISP object system (CLOS). Analytical capabilities supported within the PWA system include: complete mass balance specifications, historical characterization of selected waste streams and generation of facility profiles for materials consumption, resource utilization and worker exposure. Anticipated development activities include provisions for a best available technologies (BAT) database and integration with the LANL facilities management Geographic Information System (GIS). The environments used to develop these assessment tools will be discussed in addition to a review of initial implementation results

  3. Plume Characterization of a Laboratory Model 22 N GPIM Thruster via High-Frequency Raman Spectroscopy

    Science.gov (United States)

    Williams, George J.; Kojima, Jun J.; Arrington, Lynn A.; Deans, Matthew C.; Reed, Brian D.; Kinzbach, McKenzie I.; McLean, Christopher H.

    2015-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the capability of a green propulsion system, specifically, one using the monopropellant, AF-M315E. One of the risks identified for GPIM is potential contamination of sensitive areas of the spacecraft from the effluents in the plumes of AF-M315E thrusters. Plume characterization of a laboratory-model 22 N thruster via optical diagnostics was conducted at NASA GRC in a space-simulated environment. A high-frequency pulsed laser was coupled with an electron-multiplied ICCD camera to perform Raman spectroscopy in the near-field, low-pressure plume. The Raman data yielded plume constituents and temperatures over a range of thruster chamber pressures and as a function of thruster (catalyst) operating time. Schlieren images of the near-field plume enabled calculation of plume velocities and revealed general plume structure of the otherwise invisible plume. The measured velocities are compared to those predicted by a two-dimensional, kinetic model. Trends in data and numerical results are presented from catalyst mid-life to end-of-life. The results of this investigation were coupled with the Raman and Schlieren data to provide an anchor for plume impingement analysis presented in a companion paper. The results of both analyses will be used to improve understanding of the nature of AF-M315E plumes and their impacts to GPIM and other future missions.

  4. Effects of Combined Hands-on Laboratory and Computer Modeling on Student Learning of Gas Laws: A Quasi-Experimental Study

    Science.gov (United States)

    Liu, Xiufeng

    2006-01-01

    Based on current theories of chemistry learning, this study intends to test a hypothesis that computer modeling enhanced hands-on chemistry laboratories are more effective than hands-on laboratories or computer modeling laboratories alone in facilitating high school students' understanding of chemistry concepts. Thirty-three high school chemistry…

  5. Laboratory and modeling studies in search of the critical hydrogen concentration

    International Nuclear Information System (INIS)

    Bartels, David; Wu, Weiqiang; Kanjana, Kotchaphan; Sims, Howard; Henshaw, Jim

    2012-09-01

    The great success of hydrogen water chemistry (HWC) for primary coolant in nuclear power plants is due to the prevention of net radiolysis and to maintenance of the corrosion potential below -230 mV (SHE) where the rate of stress corrosion cracking is minimized. The critical hydrogen concentration or CHC has been defined as that concentration of excess H 2 in primary coolant water, which prevents net water radiolysis via the chain reaction OH + H 2 ↔H 2 O + H (1, -1) H + H 2 O 2 → H 2 O + OH (2) The principle oxidizing free radical (OH) is thus converted into a reducing radical (H), oxidation products are reduced back to water, and the net result is no chemical change. A set of benchmark experiments at the U2 reactor in Chalk River have been reported in an extensive AECL report, which indicate that the CHC in this reactor is ca. 25 micro-molar. Using the review of yields and reaction rates set forth in another recent AECL report, the Chalk River experiments have been modelled in work at NNL, Harwell. The model was not able to successfully reproduce the experimental CHC, or the steady-state H 2 concentrations (SSH2) in the absence of excess hydrogen. A sensitivity analysis of the entire model was carried out. Essentially three important variables have been found to dominate the result. Reaction rate (1) is overwhelmingly important in determining how much H 2 is needed to accomplish the chain back-reaction. Almost with equal importance, the back reaction (-1) needs to be considered at 300 deg. C, but there is some uncertainty of its magnitude. Finally, the relative yields of radicals and molecular products (i.e. H 2 , H 2 O 2 ) in particular H 2 :OH from the radiolysis are critical. Laboratory studies of hydrogenated water radiation chemistry have been carried out with a van de Graaff electron accelerator at Notre Dame Radiation Laboratory. Modelling of the hydrogen produced as a function of the hydrogen input, suggests that the reaction rate (-1) is ca. two

  6. Nonequilibrium Sulfur Capture & Retention in an Air Cooled Slagging Coal Combustor

    Energy Technology Data Exchange (ETDEWEB)

    Bert Zauderer

    1998-04-21

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles, which are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 36 month project was to perform a series of tests to determine the factors that control the retention of the sulfur in the slag. 19 days of testing were completed prior to 9/30/97. In the present quarterly reporting period ending 12/31/97, 13 tests days were completed on co-firing coal and a high ash, rice husk biomass, which was selected to produce a high slag flow rate. Most of the test effort focussed on developing methods for feeding the very low density rice husks into combustor. Various levels of mineral matter from coal ash, rice husk ash, calcium sulfate, and calcium oxide was injected in the combustor during these 13 tests. The peak mineral matter, injection rate was 592 lb/hr for a period of about one-hour. No significant sulfur concentration was measured in the slag removed from the combustor. This may be due to the brief test duration, and longer duration tests are planned for the next quarter. The two major accomplishments in this quarter are the successful co-firing of coal and biomass in the slagging combustor. This is a major technical milestone due to its application to greenhouse gas emission reduction. It was not in the original project plan. Also, the total of 31 test days completed by 12/31/97 is double the number originally planned.

  7. Experiments and numerical studies on a Syngas-fired Ultra low NOx combustor

    KAUST Repository

    S, Krishna

    2017-06-06

    Exhaust measurements of temperature and pollutants in a syngas-fired model trapped vortex combustor for stationary power generation applications are reported. The performance was further evaluated for configurations where mixing enhancement was obtained using struts in the mainstream flow. Mainstream premixing of fuel was also studied to investigate its effect on emissions. The exhaust temperature pattern factor was found to be poor for baseline cases, but improved with the introduction of struts. NO emissions were steadily below 3-ppm across various flow conditions, whereas CO emissions tended to increase with increasing Momentum Flux Ratios (MFRs) and mainstream fuel addition. Combustion efficiencies ~96% were observed for all conditions. The performance characteristics were found to be favourable at higher MFRs with low pattern factors and high combustion efficiencies. Numerical simulations employing RANS and LES with Presumed Probability Distribution Function (PPDF) model were also carried out. Mixture fraction profiles in the TVC cavity for non-reacting conditions show that LES simulations are able to capture the mean mixing field better than the RANS-based approach. This is attributed to the prediction of the jet decay rate and is reflected on the mean velocity magnitude fields, which reinforce this observation at different sections in the cavity. Both RANS and LES simulations show close agreement with the experimentally measured OH concentration, however, the RANS approach does not perform satisfactorily in capturing the trend of velocity magnitude. LES simulations clearly capture the trend observed in exhaust measurements which is primarily attributed to the flame stabilization mechanism.

  8. Laboratory And Lysimeter Experimentation And Transport Modeling Of Neptunium And Strontium In Savannah River Site Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Daniel I.; Powell, B. A.; Miller, Todd J.

    2012-09-24

    existing data sets. The first data set used laboratory generated Np sorption data as a function of concentration (three orders of magnitude) and as a function of pH (four orders of magnitude of proton concentration). In this modeling exercise, a very simple solution was identified by assuming that all sorption occurred only to the iron oxides in the sediment and that all the added NpO{sub 4}{sup -} remained in the oxidized state and was not reduced to the Np(IV) state (as occurs rapidly with Pu(V)). With rather limited input data, very good agreement between experimental and modeling results was observed. This modeling approach would be easy to add to the PA with little additional data requirements. This model would be useful in a system where pH is expected to change greatly, such as directly beneath a grout or concrete structure. The second model discussed in the report was to derive strontium K{sub d} values from data collected in an 11-year-old field transport study. In this controlled lysimeter study, a sensitivity analysis was conducted of hydrological and chemical processes that influence contaminant transport, including diffusion coefficients, seepage velocity, and K{sub d} value. The best overall K{sub d} derived from the model fit to the data was 32 L kg{sup -1}, which was the same value that was previously measured in traditional laboratory batch sorption studies. This was an unexpected result given the differences in experimental conditions between the batch test and the lysimeter flow through test, in particular the differences between strontium adsorption and desorption processes occurring in the latter test and not in the former. There were some trends in the lysimeter strontium data that were not predicted by the K{sub d} model, which suggest that other geochemical processes are likely also controlling strontium transport. Strontium release and cation exchange are being evaluated. These results suggest that future modeling efforts (e.g., PAs) could be

  9. Inventory of data bases, models, and graphics packages at the Pacific Northwest Laboratory

    International Nuclear Information System (INIS)

    Dionne, P.J.; Mathisen, D.I.

    1978-10-01

    The Information Coordination Focal Point (ICFP) was initiated in FY77 because DOE had a need for improved access to information at the Lawrence Berkeley Laboratory, the Savannah River Laboratory, and the six DOE national laboratories. The task for FY77 was to establish guidelines and procedures for this activity with plans of implementing the procedures in FY78 and FY79. The purpose of this report is to document the progress that has been made during FY78 for this project

  10. Inventory of data bases, models, and graphics packages at the Pacific Northwest Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Dionne, P.J.; Mathisen, D.I.

    1978-10-01

    The Information Coordination Focal Point (ICFP) was initiated in FY77 because DOE had a need for improved access to information at the Lawrence Berkeley Laboratory, the Savannah River Laboratory, and the six DOE national laboratories. The task for FY77 was to establish guidelines and procedures for this activity with plans of implementing the procedures in FY78 and FY79. The purpose of this report is to document the progress that has been made during FY78 for this project.

  11. Interim report on the laboratory and theoretical work in modeling the drained and undrained behavior of buffer materials

    International Nuclear Information System (INIS)

    Boergesson, L.

    1990-12-01

    This report describes the continuous work of modeling the geotechnical properties of buffer materials. Some results of laboratory work with drained and undrained tests are described as well as the material models that these test have yielded. The effective stress concept and its relevance is discussed. The technique to apply the models in calculations using the finite element program ABAQUS is described. Some calculations of laboratory verification tests are shown and the results compared. Finally two examples of scenario calculations are shown. The work has led to three material models that can be used in ABAQUS calculations. All parameters for these models are not fully known and a continuation of the work is required. These models are not suitable for all situations and the relevance and need for further developments are presently investigated. (au)

  12. Non-Fickian dispersive transport of strontium in laboratory-scale columns: Modelling and evaluation

    Science.gov (United States)

    Liu, Dongxu; Jivkov, Andrey P.; Wang, Lichun; Si, Gaohua; Yu, Jing

    2017-06-01

    In the context of environmental remediation of contaminated sites and safety assessment of nuclear waste disposal in the near-surface zone, we investigate the leaching and non-Fickian dispersive migration with sorption of strontium (mocking strontium-90) through columns packed with sand and clay. Analysis is based on breakthrough curves (BTCs) from column experiments, which simulated rainfall infiltration and source term release scenario, rather than applying constant tracer solution at the inlet as commonly used. BTCs are re-evaluated and transport parameters are estimated by inverse modelling using two approaches: (1) equilibrium advection-dispersion equation (ADE); and (2) continuous time random walk (CTRW). Firstly, based on a method for calculating leach concentration, the inlet condition with an exponential decay input is identified. Secondly, the results show that approximately 39%-58% of Br- and 16%-49% of Sr2+ are eluted from the columns at the end of the breakthrough experiments. This suggests that trapping mechanisms, including diffusion into immobile zones and attachment of tracer on mineral surfaces, are more pronounced for Sr2+ than for Br-. Thirdly, we demonstrate robustness of CTRW-based truncated power-law (TPL) model in capturing non-Fickian reactive transport with 0 2. The non-Fickian dispersion observed experimentally is explained by variations of local flow field from preferential flow paths due to physical heterogeneities. Particularly, the additional sorption process of strontium on clay minerals contributes to the delay of the peak concentration and the tailing features, which leads to an enhanced non-Fickian transport for strontium. Finally, the ADE and CTRW approaches to environmental modelling are evaluated. It is shown that CTRW with a sorption term can describe non-Fickian dispersive transport of strontium at laboratory scale by identifying appropriate parameters, while the traditional ADE with a retardation factor fails to reproduce

  13. Use of latent class models to accommodate inter-laboratory variation in assessing genetic polymorphisms associated with disease risk

    Directory of Open Access Journals (Sweden)

    Walter Stephen D

    2008-08-01

    Full Text Available Abstract Background Researchers wanting to study the association of genetic factors with disease may encounter variability in the laboratory methods used to establish genotypes or other traits. Such variability leads to uncertainty in determining the strength of a genotype as a risk factor. This problem is illustrated using data from a case-control study of cervical cancer in which some subjects were independently assessed by different laboratories for the presence of a genetic polymorphism. Inter-laboratory agreement was only moderate, which led to a very wide range of empirical odds ratios (ORs with the disease, depending on how disagreements were treated. This paper illustrates the use of latent class models (LCMs and to estimate OR while taking laboratory accuracy into account. Possible LCMs are characterised in terms of the number of laboratory measurements available, and if their error rates are assumed to be differential or non-differential by disease status and/or laboratory. Results The LCM results give maximum likelihood estimates of laboratory accuracy rates and the OR of the genetic variable and disease, and avoid the ambiguities of the empirical results. Having allowed for possible measurement error in the expure, the LCM estimates of exposure – disease associations are typically stronger than their empirical equivalents. Also the LCM estimates exploit all the available data, and hence have relatively low standard errors. Conclusion Our approach provides a way to evaluate the association of a polymorphism with disease, while taking laboratory measurement error into account. Ambiguities in the empirical data arising from disagreements between laboratories are avoided, and the estimated polymorphism-disease association is typically enhanced.

  14. Fuel burner and combustor assembly for a gas turbine engine

    Science.gov (United States)

    Leto, Anthony

    1983-01-01

    A fuel burner and combustor assembly for a gas turbine engine has a housing within the casing of the gas turbine engine which housing defines a combustion chamber and at least one fuel burner secured to one end of the housing and extending into the combustion chamber. The other end of the fuel burner is arranged to slidably engage a fuel inlet connector extending radially inwardly from the engine casing so that fuel is supplied, from a source thereof, to the fuel burner. The fuel inlet connector and fuel burner coact to anchor the housing against axial movement relative to the engine casing while allowing relative radial movement between the engine casing and the fuel burner and, at the same time, providing fuel flow to the fuel burner. For dual fuel capability, a fuel injector is provided in said fuel burner with a flexible fuel supply pipe so that the fuel injector and fuel burner form a unitary structure which moves with the fuel burner.

  15. CO2 release experiment in the shallow subsurface at the Brackenridge Field Laboratory and numerical modeling

    Science.gov (United States)

    Yang, C.; Romanak, K.; Hovorka, S.

    2009-12-01

    Soil gas monitoring is one cost-effective approach to detect CO2 leak at geological sequestration sites. Therefore understanding CO2 gas transport in soil zones is important for detection of CO2 leaks. A field experiment of a small CO2 release was conducted at the Brackenridge Field Laboratory, the University of Texas at Austin. The field site consists of one injection well, two sensor wells and one gas station well (Figure 1). The injection well was completed with a PVC pipe to a depth of 1.1 m below surface. CO2 sensors were deployed in sensor wells about 42 cm from the injection well at depths of 1.1 m having no subsurface PVC pipes but only a PVC protector cap at the surface. The gas monitoring station about 72 cm away from the injection well contains 3 copper tubes each set at different depths in sand pack isolated with bentonite clay. The CO2 release experiment started on March 4, 2009. A total 36.76 liters of CO2 were injected at 1 m depth at a rate of 100 ml/minute for 6 hours. Subsurface CO2 gas concentrations (before, during, and after the injection) were continuously monitored in sensor wells. Real-time CO2 concentrations were monitored at the gas station using an SRI 8610 gas chromatograph (GC) fitted with flame ionization detector (FID) and a thermal conductivity detector (TCD). A numerical model was constructed to simulate CO2 release experiments. The model takes into account CO2 diffusion and dissolution in pore water. Air in the pore space is assumed stagnant. Model domain consists of four soil layers and one atmospheric layer. The groundwater table is about 2.4 meters below ground surface. The model was calibrated with respect to diffusion coefficient (transport parameter) and the injection rate (mass parameter). Model results fit well with CO2 measurements at the sensor wells and the gas station. However, the calibrated injection rate underestimates measured injection rate.

  16. The effect of inlet conditions on lean premixed gas turbine combustor performance

    Science.gov (United States)

    Vilayanur, Suresh Ravi

    The combustion community is today faced with the goal to reduce NOx at high efficiencies. This requirement has directed attention to the manner by which air and fuel are treated prior to and at the combustor inlet. This dissertation is directed to establishing the role of combustor inlet conditions on combustor performance, and to deriving an understanding of the relationship between inlet conditions and combustion performance. To investigate the complex effect of inlet parameters on combustor performance, (1) a test facility was designed and constructed, (2) hardware was designed and fabricated, (3) a statistically based technique was designed and applied, and (4) detailed in-situ measurements were acquired. Atmospheric tests were performed at conditions representative of industrial combustors: 670 K inlet preheat and an equivalence ratio of 0.47, and make the study immediately relevant to the combustion community. The effects of premixing length, fuel distribution, swirl angle, swirl vane thickness and swirl solidity were investigated. The detailed in-situ measurements were performed to form the database necessary to study the responsible mechanisms. A host of conventional and advanced diagnostics were used for the investigation. In situ measurements included the mapping of the thermal and velocity fields of the combustor, obtaining species concentrations inside the combustor, and quantifying the fuel-air mixing entering the combustor. Acoustic behavior of the combustor was studied, including the application of high speed videography. The results reveal that the principal statistically significant effect on NOx production is the inlet fuel distribution, and the principal statistically significant effect on CO production is the swirl strength. Elevated levels of NOx emission result when the fuel is weighted to the centerline. Eddies shedding off the swirler hub ignite as discrete packets, and due to the elevated concentrations of fuel, reach higher temperatures

  17. Beyond a Battery Hen Model?: A Computer Laboratory, Micropolitics and Educational Change

    Science.gov (United States)

    Grieshaber, Susan

    2010-01-01

    This paper investigates what happened in one Australian primary school as part of the establishment, use and development of a computer laboratory over a period of two years. As part of a school renewal project, the computer laboratory was introduced as an "innovative" way to improve the skills of teachers and children in information and…

  18. Coal-Based Oxy-Fuel System Evaluation and Combustor Development; Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hollis, Rebecca

    2013-03-31

    Clean Energy Systems, Inc. (CES) partnered with the U.S. Department of Energy’s National Energy Technology Laboratory in 2005 to study and develop a competing technology for use in future fossil-fueled power generation facilities that could operate with near zero emissions. CES’s background in oxy-fuel (O-F) rocket technology lead to the award of Cooperative Agreement DE-FC26-05NT42645, “Coal-Based Oxy-Fuel System Evaluation and Combustor Development,” where CES was to first evaluate the potential of these O-F power cycles, then develop the detailed design of a commercial-scale O-F combustor for use in these clean burning fossil-fueled plants. Throughout the studies, CES found that in order to operate at competitive cycle efficiencies a high-temperature intermediate pressure turbine was required. This led to an extension of the Agreement for, “Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications” where CES was to also develop an intermediate-pressure O-F turbine (OFT) that could be deployed in O-F industrial plants that capture and sequester >99% of produced CO2, at competitive cycle efficiencies using diverse fuels. The following report details CES’ activities from October 2005 through March 2013, to evaluate O-F power cycles, develop and validate detailed designs of O-F combustors (main and reheat), and to design, manufacture, and test a commercial-scale OFT, under the three-phase Cooperative Agreement.

  19. Mars science laboratory radiation assessment detector (MSL/RAD) modeling workshop proceedings

    Science.gov (United States)

    Hassler, Donald M.; Norbury, John W.; Reitz, Günther

    2017-08-01

    The Radiation Assessment Detector (RAD) (Hassler et al., 2012; Zeitlin et al., 2016) onboard the Mars Science Laboratory (MSL) Curiosity rover (Grotzinger et al., 2012) is a sophisticated charged and neutral particle radiation analyzer developed by an international team of scientists and engineers from Southwest Research Institute in Boulder, Colorado as the leading institution, the University of Kiel and the German Aerospace Center in Cologne, Germany. RAD is a compact, powerful instrument capable of distinguishing between ionizing particles and neutral particles and providing neutron, gamma, and charged particle spectra from protons to iron as well as absorbed dose measurements in tissue-equivalent material. During the 6 month cruise to Mars, inside the MSL spacecraft, RAD served as a proxy to validate models of the radiation levels expected inside a spacecraft that future astronauts might experience (Zeitlin et al., 2013). RAD was turned on one day after the landing on August 7, 2012, exactly 100 years to the day after the discovery of cosmic rays on Earth by Victor Hess. These measurements are the first of their kind on the surface of another planet (Hassler et al., 2014), and the radiation data collected by RAD on the surface of Mars will inform projections of crew health risks and the design of protective surface habitats and other countermeasures for future human missions in the coming decades.

  20. Mixing in Long Cylinder by a Stratified Jet: Laboratory Modeling and Theory

    Science.gov (United States)

    Nath, C.; Voropayev, S. I.; Fernando, H. J. S.

    2011-11-01

    The evolution of buoyant turbulent jets released into a low aspect ratio (width/height) cavity filled with a homogeneous fluid was investigated experimentally. The motivation was to understand mixing process in U.S. Strategic Petroleum Reserves (SPR), where crude oil is stored in salt caverns of aspect ratio approximately 0.1. During maintenance, degassed oil is introduced as a jet from the top of the caverns while denser gas-laden crude oil is pumped out from the bottom. The focus was on mixing, formation and development of density layer as well as the time for replenishing oil in the container to an acceptable level of vapor pressure (gas concentration). Basing on the results of experiments a theoretical model was advanced which permits to calculate the vertical density distributions in cavern as a function of time and other external parameters. Satisfactory agreement between theory and measurements was demonstrated. The results obtained could be extrapolated to SPR flow mixing situations and help to improve the efficiency of expensive oil cavern refilling. This research is supported by the Sandia National Laboratories.

  1. Uncertainty Analysis of Resistance Tests in Ata Nutku Ship Model Testing Laboratory of Istanbul Technical University

    Directory of Open Access Journals (Sweden)

    Cihad DELEN

    2015-12-01

    Full Text Available In this study, some systematical resistance tests, where were performed in Ata Nutku Ship Model Testing Laboratory of Istanbul Technical University (ITU, have been included in order to determine the uncertainties. Experiments which are conducted in the framework of mathematical and physical rules for the solution of engineering problems, measurements, calculations include uncertainty. To question the reliability of the obtained values, the existing uncertainties should be expressed as quantities. The uncertainty of a measurement system is not known if the results do not carry a universal value. On the other hand, resistance is one of the most important parameters that should be considered in the process of ship design. Ship resistance during the design phase of a ship cannot be determined precisely and reliably due to the uncertainty resources in determining the resistance value that are taken into account. This case may cause negative effects to provide the required specifications in the latter design steps. The uncertainty arising from the resistance test has been estimated and compared for a displacement type ship and high speed marine vehicles according to ITTC 2002 and ITTC 2014 regulations which are related to the uncertainty analysis methods. Also, the advantages and disadvantages of both ITTC uncertainty analysis methods have been discussed.

  2. Laboratory modelling of the wind-wave interaction with modified PIV-method

    Directory of Open Access Journals (Sweden)

    Sergeev Daniil

    2017-01-01

    Full Text Available Laboratory experiments on studying the structure of the turbulent air boundary layer over waves were carried out at the Wind-Wave Flume of the Large Thermostratified Tank of the Institute of Applied Physics, Russian Academy of Sciences (IAP RAS, in conditions modeling the near water boundary layer of the atmosphere under strong and hurricane winds and the equivalent wind velocities from 10 to 48 m/s at the standard height of 10 m. A modified technique of Particle Image Velocimetry (PIV was used to obtain turbulent pulsation averaged velocity fields of the air flow over the water surface curved by a wave and average profiles of the wind velocity. The main modifications are: 1 the use of high-speed video recording (1000-10000 frames/sec with continuous laser illumination helps to obtain ensemble of the velocity fields in all phases of the wavy surface for subsequent statistical processing; 2 the development and application of special algorithms for obtaining form of the curvilinear wavy surface of the images for the conditions of parasitic images of the particles and the droplets in the air side close to the surface; 3 adaptive cross-correlation image processing to finding the velocity fields on a curved grid, caused by wave boarder; 4 using Hilbert transform to detect the phase of the wave in which the measured velocity field for subsequent appropriate binning within procedure obtaining the average characteristics.

  3. Laboratory modelling of the wind-wave interaction with modified PIV-method

    Science.gov (United States)

    Sergeev, Daniil; Kandaurov, Alexander; Troitskaya, Yuliya; Caulliez, Guillemette; Bopp, Maximilian; Jaehne, Bernd

    Laboratory experiments on studying the structure of the turbulent air boundary layer over waves were carried out at the Wind-Wave Flume of the Large Thermostratified Tank of the Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), in conditions modeling the near water boundary layer of the atmosphere under strong and hurricane winds and the equivalent wind velocities from 10 to 48 m/s at the standard height of 10 m. A modified technique of Particle Image Velocimetry (PIV) was used to obtain turbulent pulsation averaged velocity fields of the air flow over the water surface curved by a wave and average profiles of the wind velocity. The main modifications are: 1) the use of high-speed video recording (1000-10000 frames/sec) with continuous laser illumination helps to obtain ensemble of the velocity fields in all phases of the wavy surface for subsequent statistical processing; 2) the development and application of special algorithms for obtaining form of the curvilinear wavy surface of the images for the conditions of parasitic images of the particles and the droplets in the air side close to the surface; 3) adaptive cross-correlation image processing to finding the velocity fields on a curved grid, caused by wave boarder; 4) using Hilbert transform to detect the phase of the wave in which the measured velocity field for subsequent appropriate binning within procedure obtaining the average characteristics.

  4. Influence of the burner swirl on the azimuthal instabilities in an annular combustor

    Science.gov (United States)

    Mazur, Marek; Nygård, Håkon; Worth, Nicholas; Dawson, James

    2017-11-01

    Improving our fundamental understanding of thermoacoustic instabilities will aid the development of new low emission gas turbine combustors. In the present investigation the effects of swirl on the self-excited azimuthal combustion instabilities in a multi-burner annular annular combustor are investigated experimentally. Each of the burners features a bluff body and a swirler to stabilize the flame. The combustor is operated with an ethylene-air premixture at powers up to 100 kW. The swirl number of the burners is varied in these tests. For each case, dynamic pressure measurements at different azimuthal positions, as well as overhead imaging of OH* of the entire combustor are conducted simultaneously and at a high sampling frequency. The measurements are then used to determine the azimuthal acoustic and heat release rate modes in the chamber and to determine whether these modes are standing, spinning or mixed. Furthermore, the phase shift between the heat release rate and pressure and the shape of these two signals are analysed at different azimuthal positions. Based on the Rayleigh criterion, these investigations allow to obtain an insight about the effects of the swirl on the instability margins of the combustor. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant agreement n° 677931 TAIAC).

  5. Study on the Effect of Air Throttling on Flame Stabilization of an Ethylene Fueled Scramjet Combustor

    Directory of Open Access Journals (Sweden)

    Ye Tian

    2015-01-01

    Full Text Available The effect of air throttling on flame stabilization of an ethylene fueled scramjet combustor was investigated by numerical simulation and experiments in this paper. The results were obtained under the inflow condition with Mach number of 2.0, total temperature of 900 K, total pressure of 0.8 MPa, and total equivalence ratio of 0.5. The shock train generated by air throttling had a big effect on the flow structure of the scramjet combustor. Compared with the combustor without air throttling, the flow field with air throttling had a lower velocity and higher pressure, temperature, and vortices intensity. Air throttling was an effective way to achieve flame stabilization; the combustion in the combustor without air throttling was nearly blowout. In the experiment, the combustion was nearly blowout with air throttling location of 745 mm, and the fuel/air mixture in the combustor with air throttling location of 875 mm was burned intensively. It was important to choose the location and time sequence of air throttling for fuel ignition and flame stabilization. The numerical simulation results agreed well with experimental measurements.

  6. Combustion Dynamic Characteristics Identification in a 9-point LDI Combustor Under Choked Outlet Boundary Conditions

    Science.gov (United States)

    He, Zhuohui J.; Chang, Clarence T.

    2017-01-01

    Combustion dynamics data were collected at the NASA Glenn Research Center's CE-5 flame tube test facility under combustor outlet choked conditions. Two 9-point Swirl-Venturi Lean Direct Injection (SV-LDI) configurations were tested in a rectangular cuboid combustor geometry. Combustion dynamic data were measured at different engine operational conditions up to inlet air pressure and temperature of 24.13 bar and 828 K, respectively. In this study, the effects of acoustic cavity resonance, precessing vortex core (PVC), and non-uniform thermal expansion on the dynamic noise spectrum are identified by comparing the dynamic data that collected at various combustor inlet conditions along with combustor geometric calculations. The results show that the acoustic cavity resonance noises were seen in the counter-rotating pilot configuration but not in the co-rotating pilot configuration. Dynamic pressure noise band at around 0.9 kHz was only detected at the P'41 location (9.8 cm after fuel injector face) but not at the P'42 location (29 cm after the fuel injector face); the amplitude of this noise band depended on the thermal expansion ratio (T4/T3). The noise band at around 1.8 kHz was found to depend on the inlet air pressure or the air density inside the combustor. The PVC frequency was not observed in these two configurations.

  7. Laboratory measurements and model sensitivity studies of dust deposition ice nucleation

    Directory of Open Access Journals (Sweden)

    G. Kulkarni

    2012-08-01

    Full Text Available We investigated the ice nucleating properties of mineral dust particles to understand the sensitivity of simulated cloud properties to two different representations of contact angle in the Classical Nucleation Theory (CNT. These contact angle representations are based on two sets of laboratory deposition ice nucleation measurements: Arizona Test Dust (ATD particles of 100, 300 and 500 nm sizes were tested at three different temperatures (−25, −30 and −35 °C, and 400 nm ATD and kaolinite dust species were tested at two different temperatures (−30 and −35 °C. These measurements were used to derive the onset relative humidity with respect to ice (RHice required to activate 1% of dust particles as ice nuclei, from which the onset single contact angles were then calculated based on CNT. For the probability density function (PDF representation, parameters of the log-normal contact angle distribution were determined by fitting CNT-predicted activated fraction to the measurements at different RHice. Results show that onset single contact angles vary from ~18 to 24 degrees, while the PDF parameters are sensitive to the measurement conditions (i.e. temperature and dust size. Cloud modeling simulations were performed to understand the sensitivity of cloud properties (i.e. ice number concentration, ice water content, and cloud initiation times to the representation of contact angle and PDF distribution parameters. The model simulations show that cloud properties are sensitive to onset single contact angles and PDF distribution parameters. The comparison of our experimental results with other studies shows that under similar measurement conditions the onset single contact angles are consistent within ±2.0 degrees, while our derived PDF parameters have larger discrepancies.

  8. Development of a safer laboratory vervet monkey model for the study of human African trypanosomiasis

    Directory of Open Access Journals (Sweden)

    Maxwell Waema

    2014-10-01

    Full Text Available Background: There are three subspecies of Trypanosoma brucei: T. b. gambiense, T. b. rhodesiense and T. b. brucei. The first two are infectious to humans, whilst T. b. brucei is not. Identifying an animal model of T. b. brucei that mimics human African trypanosomiasis (HAT would enable researchers to study HAT without subjecting themselves to undue risks such as accidental infection. Objectives: This study assessed the sequential clinical, parasitological and haematological changes in vervet monkeys infected with T. b. brucei. Methods: Three vervet monkeys were infected with a 104 inoculum of T. b. brucei (isolate GUTat 1. Late-stage disease was induced by subcurative treatment with diminazene aceturate 28 days post-infection. The animals were treated curatively with melarsoprol upon relapse. Parasitaemia and clinical signs were monitored daily and, at weekly intervals, the monkeys’ blood and cerebrospinal fluid (CSF were sampled for haematology and parasitosis assessments, respectively. Results: The first-peak parasitaemia was observed between seven and nine days post-infection. Clinical signs associated with the disease included fever, dullness, pallor of mucous membranes, lymphadenopathy, splenomegaly and oedema. Late-stage signs included stiffness of joints and lethargy. The monkeys developed a disease associated with microcytic hypochromic anaemia. There was an initial decline, followed by an increase, in total white blood cell counts from early- to late-stage disease. Trypanosomes were detected in the CSF and there was a significant increase in white cell counts in the CSF during late-stage disease. Infected vervet monkeys displayed classical clinical symptoms, parasitological and haematological trends that were similar to monkeys infected withT.b. rhodesiense. Conclusion: The T. b. brucei vervet monkey model can be used for studying HAT without putting laboratory technicians and researchers at high risk of accidental infection.

  9. Large scale organized motion in isothermal swirling flow through an axisymmetric dump combustor

    International Nuclear Information System (INIS)

    Daddis, E.D.; Lieber, B.B.; Nejad, A.S.; Ahmed, S.A.

    1990-01-01

    This paper reports on velocity measurements that were obtained in a model axisymmetric dump combustor which included a coaxial swirler by means of a two component laser Doppler velocimeter (LDV) at a Reynolds number of 125,000. The frequency spectrum of the velocity fluctuations is obtained via the Fast Fourier Transform (FFT). The velocity field downstream of the dump plane is characterized, in addition to background turbulence, by large scale organized structures which are manifested as sharp spikes of the spectrum at relatively low frequencies. The decomposition of velocity disturbances to background turbulence and large scale structures can then be achieved through spectral methods which include matched filters and spectral factorization. These methods are demonstrated here for axial velocity obtained one step height downstream of the dump plane. Subsequent analysis of the various velocity disturbances shows that large scale structures account for about 25% of the apparent normal stresses at this particular location. Naturally, large scale structures evolve spatially and their contribution to the apparent stress tensor may vary depending on the location in the flow field

  10. Hydrogen jet combustion in a scramjet combustor with the rearwall-expansion cavity

    Science.gov (United States)

    Zhang, Yan-Xiang; Wang, Zhen-Guo; Sun, Ming-Bo; Yang, Yi-Xin; Wang, Hong-Bo

    2018-03-01

    This study is carried out to experimentally investigate the combustion characteristics of the hydrogen jet flame stabilized by the rearwall-expansion cavity in a model scramjet combustor. The flame distributions are characterized by the OH* spontaneous emission images, and the dynamic features of the flames are studied through the high speed framing of the flame luminosity. The combustion modes are further analyzed based on the visual flame structure and wall pressure distributions. Under the present conditions, the combustion based on the rearwall-expansion cavity appears in two distinguished modes - the typical cavity shear-layer stabilized combustion mode and the lifted-shear-layer stabilized combustion mode. In contrast with the shear-layer stabilized mode, the latter holds stronger flame. The transition from shear-layer stabilized combustion mode to lifted-shear-layer stabilized mode usually occurs when the equivalence ratio is high enough. While the increases of the offset ratio and upstream injection distance both lead to weaker jet-cavity interactions, cause longer ignition delay, and thus delay the mode transition. The results reveal that the rearwall-expansion cavity with an appropriate offset ratio should be helpful in delaying mode transition and preventing thermal choke, and meanwhile just brings minor negative impact on the combustion stability and efficiency.

  11. Near-infrared diode laser absorption diagnostic for temperature and water vapor in a scramjet combustor

    International Nuclear Information System (INIS)

    Liu, Jonathan T.C.; Rieker, Gregory B.; Jeffries, Jay B.; Gruber, Mark R.; Carter, Campbell D.; Mathur, Tarun; Hanson, Ronald K.

    2005-01-01

    Tunable diode laser absorption measurements of gas temperature and water concentration were made at the exit of a model scramjet combustor fueled on JP-7. Multiplexed, fiber-coupled, near-infrared distributed feedback lasers were used to probe three water vapor absorption features in the 1.34-1.47 μm spectral region (2v1and v1+ v3overtone bands). Ratio thermometry was performed using direct-absorption wavelength scans of isolated features at a 4-kHz repetition rate, as well as 2f wavelength modulation scans at a 2-kHz scan rate. Large signal-to-noise ratios demonstrate the ability of the optimally engineered optical hardware to reject beam steering and vibration noise. Successful measurements were made at full combustion conditions for a variety of fuel/air equivalence ratios and at eight vertical positions in the duct to investigate spatial uniformity. The use of three water vapor absorption features allowed for preliminary estimates of temperature distributions along the line of sight. The improved signal quality afforded by 2f measurements, in the case of weak absorption, demonstrates the utility of a scanned wavelength modulation strategy in such situations

  12. Fluid dynamic simulation of the fluidized bed using propane-air fuel; Simulacao dinamica de um combustor de leito fluidizado utilizando como combustivel o ar-propanado

    Energy Technology Data Exchange (ETDEWEB)

    Lima Junior, L.P.; Lucena, S.; Silva, D.J. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica]. E-mail: limajun@br.inter.net

    2004-07-01

    This paper has for purpose to present the modeling and simulation of the homogeneous combustion of the mixture of propane-air in a combustor of fluidized bed with inert particles, basing on a stationary model with phases in series, being taken into account the thermal changes and mass changes among the phases and it changes thermal with the wall for radiation. Computational methods are used for such simulation and CFX 4.4 as dynamic flowing computation software (CFD), kindred of more proximity with the real aspects. Being studied like this dynamic and kinetic flowing parameters of the involved components. (author)

  13. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62.14103 Protection of... combustor metals, acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste... nitrogen oxides in excess of the emission limits listed in table 2 of this subpart for affected facilities...

  14. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  15. 40 CFR Appendix to Subpart Eee of... - Quality Assurance Procedures for Continuous Emissions Monitors Used for Hazardous Waste Combustors

    Science.gov (United States)

    2010-07-01

    ... determination and adjustment of CEMS. 4. Integration of CEMS with the automatic waste feed cutoff (AWFCO) system... Continuous Emissions Monitors Used for Hazardous Waste Combustors Appendix to Subpart EEE of Part 63... Hazardous Air Pollutants from Hazardous Waste Combustors Pt. 63, Subpt. EEE, App. Appendix to Subpart EEE of...

  16. Validating the Technology Acceptance Model in the Context of the Laboratory Information System-Electronic Health Record Interface System

    Science.gov (United States)

    Aquino, Cesar A.

    2014-01-01

    This study represents a research validating the efficacy of Davis' Technology Acceptance Model (TAM) by pairing it with the Organizational Change Readiness Theory (OCRT) to develop another extension to the TAM, using the medical Laboratory Information Systems (LIS)--Electronic Health Records (EHR) interface as the medium. The TAM posits that it is…

  17. Use of a PhET Interactive Simulation in General Chemistry Laboratory: Models of the Hydrogen Atom

    Science.gov (United States)

    Clark, Ted M.; Chamberlain, Julia M.

    2014-01-01

    An activity supporting the PhET interactive simulation, Models of the Hydrogen Atom, has been designed and used in the laboratory portion of a general chemistry course. This article describes the framework used to successfully accomplish implementation on a large scale. The activity guides students through a comparison and analysis of the six…

  18. Rhetoric Versus Reality? Laboratory Surveys Show Actual Practice Differs Considerably from Proposed Models and Mandated Calculations.

    Science.gov (United States)

    Westgard, Sten A

    2017-03-01

    The scientific debate on goals, measurement uncertainty, and individualized quality control plans has diverged significantly from the reality of laboratory operation. Academic articles promoting certain approaches are being ignored; laboratories may be in compliance with new regulations, mandates, and calculations, but most of them still adhere to traditional quality management practices. Despite a considerable effort to enforce measurement uncertainty and eliminate or discredit allowable total error, laboratories continue to use these older, more practical approaches for quality management. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Evaluation of an FDA approved library against laboratory models of human intestinal nematode infections.

    Science.gov (United States)

    Keiser, Jennifer; Panic, Gordana; Adelfio, Roberto; Cowan, Noemi; Vargas, Mireille; Scandale, Ivan

    2016-07-01

    Treatment options for infections with soil-transmitted helminths (STH) - Ascaris lumbricoides, Trichuris trichiura and the two hookworm species, Ancylostoma duodenale and Necator americanus - are limited despite their considerable global health burden. The aim of the present study was to test the activity of an openly available FDA library against laboratory models of human intestinal nematode infections. All 1,600 drugs were first screened against Ancylostoma ceylanicum third-stage larvae (L3). Active compounds were scrutinized and toxic compounds, drugs indicated solely for topical use, and already well-studied anthelmintics were excluded. The remaining hit compounds were tested in parallel against Trichuris muris first-stage larvae (L1), Heligmosomoides polygyrus third-stage larvae (L3), and adult stages of the three species in vitro. In vivo studies were performed in the H. polygyrus and T. muris mice models. Fifty-four of the 1,600 compounds tested revealed an activity of > 60 % against A. ceylanicum L3 (hit rate of 3.4 %), following incubation at 200 μM for 72 h. Twelve compounds progressed into further screens. Adult A. ceylanicum were the least affected (1/12 compounds active at 50 μM), while eight of the 12 test compounds revealed activity against T. muris L1 (100 μM) and adults (50 μM), and H. polygyrus L3 (200 μM). Trichlorfon was the only compound active against all stages of A. ceylanicum, H. polygyrus and T. muris. In addition, trichlorfon achieved high worm burden reductions of 80.1 and 98.9 %, following a single oral dose of 200 mg/kg in the T. muris and H. polygyrus mouse model, respectively. Drug screening on the larval stages of intestinal parasitic nematodes is feasible using small libraries and important given the empty drug discovery and development pipeline for STH infections. Differences and commonalities in drug activities across the different STH species and stages were confirmed. Hits identified might serve as a

  20. Emissions of nitrogen oxides from an experimental hydrogen-fueled gas turbine combustor

    Science.gov (United States)

    Norgren, C. T.; Ingebo, R. D.

    1974-01-01

    The effect of operating variables of a hydrogen fueled combustor on exhaust concentrations of total oxides of nitrogen was determined at inlet-air temperature levels up to 810 K, pressure of 414,000N/sa m, and reference velocity of 21.3 m/sec. The combustor, which was originally designed for hydrocarbon fuel produced a NO(x) concentration of 380 ppm with hydrogen at 810 K inlet-air temperature. A reduction in NO(x) of about 30 % was obtained by modification to a lean or rich primary zone. The lowest NO(x) levels obtained with hydrogen were equivalent to those of the reference combustor burning hydrocarbon fuels.

  1. Experimental and analytical separation of hydrodynamic, entropy and combustion noise in a gas turbine combustor

    Science.gov (United States)

    Muthukrishnan, M.; Strahle, W. C.; Neale, D. H.

    1977-01-01

    This paper deals with noise sources which are central to the problem of core engine noise in turbopropulsion systems. The sources dealt with are entropy noise and direct combustion noise, as well as a non-propagating psuedosound which is hydrodynamic noise. It is shown analytically and experimentally that a transition can occur from a combustion noise dominant situation to an entropy noise dominant case if the contraction of a terminating nozzle to the combustor is high enough. In the combustor tested, entropy noise is the dominant source for propagational noise if the combustor is choked at the exit. Analysis techniques include spectral, cross spectral, cross correlation, and ordinary and partial coherence analysis. Measurements include exterior and interior fluctuating and mean pressures and temperatures.

  2. An emissions audit of a biomass combustor burning treated wood waste

    International Nuclear Information System (INIS)

    Jackson, P.M.; Jones, H.H.; King, P.G.

    1993-01-01

    This report describes the Emissions Audit carried out on a Biomass Combustor burning treated wood waste at the premises of a furniture manufacturer. The Biomass Combustor was tested in two firing modes; continuous fire and modulating fire. Combustion chamber temperatures and gas residence times were not measured. Boiler efficiencies were very good at greater than 75% in both tests. However, analysis of the flue gases indicated that improved efficiencies are possible. The average concentrations of CO (512mgm -3 ) and THC (34mgm -3 ) for Test 1 were high, indicating that combustion was poor. The combustor clearly does not meet the requirements of the Guidance Note for the Combustion of Wood Waste. CO 2 and O 2 concentrations were quite variable showing that combustion conditions were fairly unstable. Improved control of combustion should lead to acceptable emission concentrations. (Author)

  3. Investigation of combustion in miniaturised combustor for application to micro gas turbines

    Science.gov (United States)

    Guidez, J.; Roux, P.; Poirson, N.; Jourdanneau, E.; Orain, M.; Grisch, F.

    2009-09-01

    Assessing the feasibility of combustion in miniaturised combustors (volume less than 1 cm3) is a key point for the development of micro gas turbines. This paper presents the results obtained in a combustion chamber operating with a hydrogen-air mixture. A stable combustion was obtained with an output power between 100 and 1200 W, for air mass flow rate from 0.1 to 0.5 g/s, and equivalence ratio between 0.3 and 0.7. Experimental results were obtained using thermocouples to measure temperature of the burnt gases at the outlet of the combustor, and information on combustion efficiency and output power was derived. In addition, laser-based measurements were performed using spontaneous Raman spectroscopy and Rayleigh scattering to determine radial profiles of temperature and main species concentrations at the outlet of the combustor.

  4. The design and testing of a can-type combustor in a compressor test rig

    CSIR Research Space (South Africa)

    Meyers, Bronwyn C

    2017-09-01

    Full Text Available : Start-up Design point Unit Compressor outlet data p3 221627 548506 [Pa] P3 222000 550000 [Pa] T3 295 300 [K] ?̇?𝟑 0.32 1 [kg/s] ?̇?𝒇 0.0071 0.0133 [kg/s] Turbine inlet data T4 - 800 [K] pf 20 20 [%] Combustor 𝑷𝟑𝟒 𝑷𝟑 0.053 0.053 - 𝑷𝟒... would pose little to no effect on the performance of the combustor. Table 2 The revised input values for the preliminary combustor design Condition No.: 1 2 Condition: Start-up Design point Unit Compressor outlet data p3 221627 548506 [Pa] P3...

  5. Utility gas turbine combustor viewing system: Volume 1, Conceptual design and initial field testing: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Morey, W.W.

    1988-12-01

    This report summarizes the development and field testing of a combustor viewing probe (CVP) as a flame diagnostic monitor for utility gas turbine engines. The prototype system is capable of providing a visual record of combustor flame images, recording flame spectral data, analyzing image and spectral data, and diagnosing certain engine malfunctions. The system should provide useful diagnostic information to utility plant operators, and reduce maintenance costs. The field tests demonstrated the ability of the CVP to monitor combustor flame condition and to relate changes in the engine operation with variations in the flame signature. Engine light off, run up to full speed, the addition of load, and the effect of water injection for NO/sub x/ control could easily be identified on the video monitor. The viewing probe was also valuable in identifying hard startups and shutdowns, as well as transient effects that can seriously harm the engine. 11 refs.

  6. Utility gas turbine combustor viewing system: Volume 2, Engine operating envelope test: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Morey, W.W.

    1988-12-01

    This report summarizes the development and field testing of a combustor viewing probe (CVP) as a flame diagnostic monitor for utility gas turbine engines. The prototype system is capable of providing a visual record of combustor flame images, recording flame spectral data, analyzing image and spectral data, and diagnosing certain engine malfunctions. The system should provide useful diagnostic information to utility plant operators, and reduced maintenance costs. The field tests demonstrated the ability of the CVP to monitor combustor flame condition and to relate changes in the engine operation with variations in the flame signature. Engine light off, run up to full speed, the addition of load, and the effect of water injection for NO/sub x/ control could easily be identified on the video monitor. The viewing probe was also valuable in identifying hard startups and shutdowns, as well as transient effects that can seriously harm the engine.

  7. Validation of a Numerical Model for Dynamic Three-Dimensional Railway Bridge Analysis by Comparison with a Small-Scale Laboratory Model

    DEFF Research Database (Denmark)

    Bucinskas, Paulius; Sneideris, Jonas; Agapii, Liuba

    2017-01-01

    is constructed in the laboratory, and the results are compared with the proposed computational model. The computational analysis employs a multi-degree-of-freedom system for the vehicle, a three-dimensional finite-element model for the bridge structure and a semi-analytical solution for the subsoil, using...

  8. Laboratory Experiments and Modeling for Interpreting Field Studies of Secondary Organic Aerosol Formation Using an Oxidation Flow Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Jose-Luis [Univ. of Colorado, Boulder, CO (United States)

    2016-02-01

    This grant was originally funded for deployment of a suite of aerosol instrumentation by our group in collaboration with other research groups and DOE/ARM to the Ganges Valley in India (GVAX) to study aerosols sources and processing. Much of the first year of this grant was focused on preparations for GVAX. That campaign was cancelled due to political reasons and with the consultation with our program manager, the research of this grant was refocused to study the applications of oxidation flow reactors (OFRs) for investigating secondary organic aerosol (SOA) formation and organic aerosol (OA) processing in the field and laboratory through a series of laboratory and modeling studies. We developed a gas-phase photochemical model of an OFR which was used to 1) explore the sensitivities of key output variables (e.g., OH exposure, O3, HO2/OH) to controlling factors (e.g., water vapor, external reactivity, UV irradiation), 2) develop simplified OH exposure estimation equations, 3) investigate under what conditions non-OH chemistry may be important, and 4) help guide design of future experiments to avoid conditions with undesired chemistry for a wide range of conditions applicable to the ambient, laboratory, and source studies. Uncertainties in the model were quantified and modeled OH exposure was compared to tracer decay measurements of OH exposure in the lab and field. Laboratory studies using OFRs were conducted to explore aerosol yields and composition from anthropogenic and biogenic VOC as well as crude oil evaporates. Various aspects of the modeling and laboratory results and tools were applied to interpretation of ambient and source measurements using OFR. Additionally, novel measurement methods were used to study gas/particle partitioning. The research conducted was highly successful and details of the key results are summarized in this report through narrative text, figures, and a complete list of publications acknowledging this grant.

  9. Laboratory-scale model of carbon dioxide deposition for soil stabilisation

    Directory of Open Access Journals (Sweden)

    Mohammad Hamed Fasihnikoutalab

    2016-04-01

    Full Text Available Olivine sand is a natural mineral, which, when added to soil, can improve the soil's mechanical properties while also sequester carbon dioxide (CO2 from the surrounding environment. The originality of this paper stems from the novel two-stage approach. In the first stage, natural carbonation of olivine and carbonation of olivine treated soil under different CO2 pressures and times were investigated. In this stage, the unconfined compression test was used as a tool to evaluate the strength performance. In the second stage, details of the installation and performance of carbonated olivine columns using a laboratory-scale model were investigated. In this respect, olivine was mixed with the natural soil using the auger and the columns were then carbonated with gaseous CO2. The unconfined compressive strengths of soil in the first stage increased by up to 120% compared to those of the natural untreated soil. The strength development was found to be proportional to the CO2 pressure and carbonation period. Microstructural analyses indicated the presence of magnesite on the surface of carbonated olivine-treated soil, demonstrating that modified physical properties provided a stronger and stiffer matrix. The performance of the carbonated olivine-soil columns, in terms of ultimate bearing capacity, showed that the carbonation procedure occurred rapidly and yielded a bearing capacity value of 120 kPa. Results of this study are of significance to the construction industry as the feasibility of carbonated olivine for strengthening and stabilizing soil is validated. Its applicability lies in a range of different geotechnical applications whilst also mitigates the global warming through the sequestration of CO2.

  10. Exposure to engineered nanoparticles: Model and measurements for accident situations in laboratories.

    Science.gov (United States)

    Walser, Tobias; Hellweg, Stefanie; Juraske, Ronnie; Luechinger, Norman A; Wang, Jing; Fierz, Martin

    2012-03-15

    In the life cycle of engineered nanoparticles (ENP), their manufacturing requires particular attention because of unwanted potential ENP emissions to workplaces. We simulated three scenarios of equipment failure during gas phase production of nanoparticles in a laboratory. The emission plume of nanoparticles was tracked with high spatial and temporal resolution by 10 measurement devices. While under normal production conditions, no elevated ENP concentrations were observed, worst case scenarios led to homogeneous indoor ENP concentrations of up to 10(6)cm(-3) in a 300m(3) production room after only 60s. The fast dispersal in the room was followed by an exponential decrease in number concentration after the emission event. Under conditions like those observed - rapid dispersal and good mixing - a single measurement device alone can provide valuable information for an ENP exposure assessment. A one-box model adequately reflected measured number concentrations (r(2)>0.99). The ENP emission rates to the workplace were estimated between 2.5·10(11) and 6·10(12)s(-1) for the three emission scenarios. The worst case emission rate at the production zone was also estimated at 2·10(13)s(-1) with a stoichiometric calculation based on the precursor input, density and particle size. ENP intake fractions were 3.8-5.1·10(-4) inhaled ENP per produced ENP in the investigated setting. These could only be substantially lowered by leaving the production room within a few minutes after the emission event. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. The rat: a laboratory model for studies of the diving response

    Science.gov (United States)

    Gan, Qi; Juric, Rajko

    2010-01-01

    Underwater submersion in mammals induces apnea, parasympathetically mediated bradycardia, and sympathetically mediated peripheral vasoconstriction. These effects are collectively termed the diving response, potentially the most powerful autonomic reflex known. Although these physiological responses are directed by neurons in the brain, study of neural control of the diving response has been hampered since 1) it is difficult to study the brains of animals while they are underwater, 2) feral marine mammals are usually large and have brains of variable size, and 3) there are but few references on the brains of naturally diving species. Similar responses are elicited in anesthetized rodents after stimulation of their nasal mucosa, but this nasopharyngeal reflex has not been compared directly with natural diving behavior in the rat. In the present study, we compared hemodynamic responses elicited in awake rats during volitional underwater submersion with those of rats swimming on the water's surface, rats involuntarily submerged, and rats either anesthetized or decerebrate and stimulated nasally with ammonia vapors. We show that the hemodynamic changes to voluntary diving in the rat are similar to those of naturally diving marine mammals. We also show that the responses of voluntary diving rats are 1) significantly different from those seen during swimming, 2) generally similar to those elicited in trained rats involuntarily “dunked” underwater, and 3) generally different from those seen from dunking naive rats underwater. Nasal stimulation of anesthetized rats differed most from the hemodynamic variables of rats trained to dive voluntarily. We propose that the rat trained to dive underwater is an excellent laboratory model to study neural control of the mammalian diving response, and also suggest that some investigations may be done with nasal stimulation of decerebrate preparations to decipher such control. PMID:20093670

  12. Design and Performance of a Low Btu Fuel Rich-Quench-Lean Gas Turbine Combustor

    Energy Technology Data Exchange (ETDEWEB)

    Feitelberg, A.S.; Jackson, M.R.; Lacey, M.A.; Manning, K.S.; Ritter, A.M.

    1996-12-31

    General Electric Company is developing gas turbines and a high temperature desulfurization system for use in integrated gasification combined cycle (IGCC) power plants. High temperature desulfurization, or hot gas cleanup (HGCU), offers many advantages over conventional low temperature desulfurization processes, but does not reduce the relatively high concentrations of fuel bound nitrogen (FBN) that are typically found in low Btu fuel. When fuels containing bound nitrogen are burned in conventional gas turbine combustors, a significant portion of the FBN is converted to NO{sub x}. Methods of reducing the NO{sub x} emissions from IGCC power plants equipped with HGCU are needed. Rich-quench-lean (RQL) combustion can decrease the conversion of FBN to NO{sub x} because a large fraction of the FBN is converted into non-reactive N{sub 2} in a fuel rich stage. Additional air, required for complete combustion, is added in a quench stage. A lean stage provides sufficient residence time for complete combustion. Objectives General Electric has developed and tested a rich-quench-lean gas turbine combustor for use with low Btu fuels containing FBN. The objective of this work has been to design an RQL combustor that has a lower conversion of FBN to N{sub x} than a conventional low Btu combustor and is suitable for use in a GE heavy duty gas turbine. Such a combustor must be of appropriate size and scale, configuration (can-annular), and capable of reaching ``F`` class firing conditions (combustor exit temperature = 2550{degrees}F).

  13. Radiative heat transfer in strongly forward scattering media of circulating fluidized bed combustors

    Science.gov (United States)

    Ates, Cihan; Ozen, Guzide; Selçuk, Nevin; Kulah, Gorkem

    2016-10-01

    Investigation of the effect of particle scattering on radiative incident heat fluxes and source terms is carried out in the dilute zone of the lignite-fired 150 kWt Middle East Technical University Circulating Fluidized Bed Combustor (METU CFBC) test rig. The dilute zone is treated as an axisymmetric cylindrical enclosure containing grey/non-grey, absorbing, emitting gas with absorbing, emitting non/isotropically/anisotropically scattering particles surrounded by grey diffuse walls. A two-dimensional axisymmetric radiation model based on Method of Lines (MOL) solution of Discrete Ordinates Method (DOM) coupled with Grey Gas (GG)/Spectral Line-Based Weighted Sum of Grey Gases Model (SLW) and Mie theory/geometric optics approximation (GOA) is extended for incorporation of anisotropic scattering by using normalized Henyey-Greenstein (HG)/transport approximation for the phase function. Input data for the radiation model is obtained from predictions of a comprehensive model previously developed and benchmarked against measurements on the same CFBC burning low calorific value indigenous lignite with high volatile matter/fixed carbon (VM/FC) ratio in its own ash. Predictive accuracy and computational efficiency of nonscattering, isotropic scattering and forward scattering with transport approximation are tested by comparing their predictions with those of forward scattering with HG. GG and GOA based on reflectivity with angular dependency are found to be accurate and CPU efficient. Comparisons reveal that isotropic assumption leads to under-prediction of both incident heat fluxes and source terms for which discrepancy is much larger. On the other hand, predictions obtained by neglecting scattering were found to be in favorable agreement with those of forward scattering at significantly less CPU time. Transport approximation is as accurate and CPU efficient as HG. These findings indicate that negligence of scattering is a more practical choice in solution of the radiative

  14. Formed platelet combustor liner construction feasibility, phase A

    Science.gov (United States)

    Hayes, W. A.; Janke, D. E.

    1992-09-01

    Environments generated in high pressure liquid rocket engines impose severe requirements on regeneratively cooled combustor liners. Liners fabricated for use in high chamber pressures using conventional processes suffer from limitations that can impair operational cycle life and can adversely affect wall compatibility. Chamber liners fabricated using formed platelet technology provide an alternative to conventional regeneratively cooled liners (an alternative that has many attractive benefits). A formed platelet liner is made from a stacked assembly of platelets with channel features. The assembly is diffusion bonded into a flat panel and then three-dimensionally formed into a section of a chamber. Platelet technology permits the liner to have very precisely controlled and thin hot gas walls and therefore increased heat transfer efficiency. Further cooling efficiencies can be obtained through enhanced design flexibility. These advantages translate into increased cycle life and enhanced wall compatibility. The increased heat transfer efficiency can alternately be used to increase engine performance or turbopump life as a result of pressure drop reductions within the regeneratively cooled liner. Other benefits can be obtained by varying the materials of construction within the platelet liner to enhance material compatibility with operating environment or with adjoining components. Manufacturing cost savings are an additional benefit of a formed platelet liner. This is because of reduced touch labor and reduced schedule when compared to conventional methods of manufacture. The formed platelet technology is not only compatible with current state-of-the art combustion chamber structural support and manifolding schemes, it is also an enabling technology that allows the use of other high performance and potentially low cost methods of construction for the entire combustion chamber assembly. The contract under which this report is submitted contains three phases: (1) phase

  15. Using a novel alternative to drug choice in a human laboratory model of a cocaine binge: a game of chance.

    Science.gov (United States)

    Vosburg, Suzanne K; Haney, Margaret; Rubin, Eric; Foltin, Richard W

    2010-07-01

    Human laboratory studies have shown that, once initiated, cocaine self-administration is difficult to disrupt using non-drug alternatives. This inpatient study examined whether binge self-administration of cocaine could be altered by an immediate, non-drug reinforcer. Ten cocaine-dependent participants completed 5 consecutive laboratory session days with 2 sessions per day (a model binge), 9 days where cocaine was not available, and subsequent 2 laboratory session days where cocaine was again available (a second model binge). In each laboratory session, participants could choose to either self-administer smoked cocaine or play a game of chance by drawing a pre-determined number of balls from a bingo wheel. Balls were worth monetary amounts from $0 to $20. Participants' choice to smoke cocaine varied as a function of number of balls drawn. Thus, this game of chance served as an alternative reinforcer to smoking cocaine. Choice varied lawfully as a function of the number of opportunities to earn money indicating that an immediate behavioral alternative can reduce cocaine self-administration after initiation of use. The current model could be used to evaluate whether behavioral and pharmacological manipulations shift choice from cocaine to a non-drug alternative. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  16. System for reducing combustion dynamics and NO.sub.x in a combustor

    Science.gov (United States)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Hughes, Michael John; York, William David

    2016-05-31

    A combustor includes an end cap that extends radially across at least a portion of the combustor. The end cap includes an upstream surface axially separated from a downstream surface. A plurality of tubes extend from the upstream surface through the downstream surface of the end cap to provide fluid communication through the end cap. Each tube in a first set of the plurality of tubes has an inlet proximate to the upstream surface and an outlet downstream from the downstream surface. Each outlet has a first portion that extends a different axial distance from the inlet than a second portion.

  17. Parametric performance of a turbojet engine combustor using jet A and A diesel fuel

    Science.gov (United States)

    Butze, H. F.; Humenik, F. M.

    1979-01-01

    The performance of a single-can JT8D combustor was evaluated with Jet A and a high-aromatic diesel fuel over a parametric range of combustor-inlet conditions. Performance parameters investigated were combustion efficiency, emissions of CO, unburned hydrocarbons, and NOx, as well as liner temperatures and smoke. At all conditions the use of diesel fuel instead of Jet A resulted in increases in smoke numbers and liner temperatures; gaseous emissions, on the other hand, did not differ significantly between the two fuels.

  18. Induction of a chronic myocardial infarction in the laboratory animal - experimental model

    Science.gov (United States)

    POP, IONEL CIPRIAN; GRAD, NICOLAE-OVIDIU; PESTEAN, COSMIN; TAULESCU, MARIAN; MIRCEAN, MIRCEA; MIRONIUC, ION-AUREL

    2013-01-01

    Introduction Ischemic heart disease is a major public health problem in western countries. Appropriate animal experimental models of chronic myocardial infarction is an essential first step in order to investigate and develop new therapeutic interventions. Aim The aim of this study was to find an optimal place for a coronary artery ligation to induce an optimal chronic myocardial infarction and also a new heart approach that will not require oro-tracheal intubation. Material and methods To achieve these goals we used a group of rabbits and after induction of anesthesia and cardiac exposure by rib osteotomy (rib III, IV and V) at the costo-sternal junction level on the right side we performed three different left anterior descending artery (LAD) ligation at different distances (5, 10 and 15 mm) in relation to the apex. Thirty days after the acute myocardial infarction, we correlated laboratory investigations (serology, ECG, cardiac ultrasound) with histopathological findings. Results Heart approach achieved by rib osteotomy (rib III, IV and V) at the costo-sternal junction level on the right side, maintains the integrity of the ribcage, allowing it to take part in respiratory movements and the animal model does not need oro-tracheal intubation. Ligation of LAD at 15 mm from the apex was incompatible with life; ligation of LAD at 5 mm from the apex does not achieved transmural myocardial infarction and ligation of LAD at 10 mm from the apex achieved a transmural myocardial infarction of the left ventricle which also involved the distal part of the interventricular septum. Conclusion Ligation of LAD at 10 mm from the apex achieved a transmural myocardial infarction of the left ventricle, is in an easily accessible area from technical point of view, it is sufficiently expanded to induce hemodynamic effects that can be quantified with paraclinical examination and also it is compatible with the experimental animal life. If the heart is approached by rib III, IV and V

  19. Laboratory studies and model simulations of sorbent material behavior for an in-situ passive treatment barrier

    International Nuclear Information System (INIS)

    Aloysius, D.; Fuhrmann, M.

    1995-01-01

    This paper presents a study combining laboratory experiments and model simulations in support of the design and construction of a passive treatment barrier (or filter wall) for retarding the migration of Sr-90 within a water-bearing surficial sand and gravel layer. Preliminary evaluation was used to select materials for column testing. A one-dimensional finite-difference model was used to simulate the laboratory column results and extrapolation of the calibrated model was then used to assess barrier performance over extended time frames with respect to Sr-90 breakthrough and loading on the filter media. The final results of the study showed that 20 by 50 mesh clinoptilolite will attenuate Sr-90 with a maximum life expentancy of approximately 10 years. This time period is based on allowable limits of Sr-90 activity on the filter media and is also a function of site-specific conditions

  20. Effectiveness of the Flipped Classroom Model in Anatomy and Physiology Laboratory Courses at a Hispanic Serving Institution

    Science.gov (United States)

    Sanchez, Gerardo

    A flipped laboratory model involves significant preparation by the students on lab material prior to entry to the laboratory. This allows laboratory time to be focused on active learning through experiments. The aim of this study was to observe changes in student performance through the transition from a traditional laboratory format, to a flipped format. The data showed that for both Anatomy and Physiology (I and II) laboratories a more normal distribution of grades was observed once labs were flipped and lecture grade averages increased. Chi square and analysis of variance tests showed grade changes to a statistically significant degree, with a p value of less than 0.05 on both analyses. Regression analyses gave decreasing numbers after the flipped labs were introduced with an r. 2 value of .485 for A&P I, and .564 for A&P II. Results indicate improved scores for the lecture part of the A&P course, decreased outlying scores above 100, and all score distributions approached a more normal distribution.

  1. Nuclear forensics: a comprehensive model action plan for Nuclear Forensics Laboratory in India

    International Nuclear Information System (INIS)

    Deshmukh, A.V.; Nyati, S.; Fatangre, N.M.; Raghav, N.K.; Reddy, P.G.

    2013-01-01

    Nuclear forensic is an emerging and highly specialized discipline which deals with nuclear investigation and analysis of nuclear or radiological/radioactive materials. Nuclear Forensic analysis includes various methodology and analytical methods along with morphology, physical, chemical, elemental and isotopic analysis to characterize and develop nuclear database for the identification of unknown nuclear or radiological/radioactive material. The origin, source history, pathway and attribution of unknown radioactive/nuclear material is possible with certainty through Nuclear Forensics. Establishment of Nuclear Forensic Laboratory and development of expertise for nuclear investigation under one roof by developing the nuclear data base and laboratory network is need of the hour to ably address the problems of all the law enforcement and nuclear agencies. The present study provides insight in Nuclear Forensics and focuses on an urgent need for a comprehensive plan to set up Nuclear Forensic Laboratory across India. (author)

  2. Laboratory model study of newly deposited dredger fills using improved multiple-vacuum preloading technique

    Directory of Open Access Journals (Sweden)

    Jingjin Liu

    2017-10-01

    Full Text Available Problems continue to be encountered concerning the traditional vacuum preloading method in field during the treatment of newly deposited dredger fills. In this paper, an improved multiple-vacuum preloading method was developed to consolidate newly dredger fills that are hydraulically placed in seawater for land reclamation in Lingang Industrial Zone of Tianjin City, China. With this multiple-vacuum preloading method, the newly deposited dredger fills could be treated effectively by adopting a novel moisture separator and a rapid improvement technique without sand cushion. A series of model tests was conducted in the laboratory for comparing the results from the multiple-vacuum preloading method and the traditional one. Ten piezometers and settlement plates were installed to measure the variations in excess pore water pressures and moisture content, and vane shear strength was measured at different positions. The testing results indicate that water discharge–time curves obtained by the traditional vacuum preloading method can be divided into three phases: rapid growth phase, slow growth phase, and steady phase. According to the process of fluid flow concentrated along tiny ripples and building of larger channels inside soils during the whole vacuum loading process, the fluctuations of pore water pressure during each loading step are divided into three phases: steady phase, rapid dissipation phase, and slow dissipation phase. An optimal loading pattern which could have a best treatment effect was proposed for calculating the water discharge and pore water pressure of soil using the improved multiple-vacuum preloading method. For the newly deposited dredger fills at Lingang Industrial Zone of Tianjin City, the best loading step was 20 kPa and the loading of 40–50 kPa produced the highest drainage consolidation. The measured moisture content and vane shear strength were discussed in terms of the effect of reinforcement, both of which indicate

  3. EFFECT OF COMBUSTOR INLET GEOMETRY ON ACOUSTIC SIGNATURE AND FLOW FIELD BEHAVIOUR OF THE LOW SWIRL INJECTOR

    Energy Technology Data Exchange (ETDEWEB)

    Therkelsen, Peter L.; Littlejohn, David; Cheng, Robert K.; Portillo, J. Enrique; Martin, Scott M.

    2009-11-30

    Low Swirl Injector (LSI) technology is a lean premixed combustion method that is being developed for fuel-flexible gas turbines. The objective of this study is to characterize the fuel effects and influences of combustor geometry on the LSI's overall acoustic signatures and flowfields. The experiments consist of 24 flames at atmospheric condition with bulk flows ranging between 10 and 18 m/s. The flames burn CH{sub 4} (at {phi} = 0.6 & 0.7) and a blend of 90% H{sub 2} - 10% CH{sub 4} by volume (at {phi} = 0.35 & 0.4). Two combustor configurations are used, consisting of a cylindrical chamber with and without a divergent quarl at the dump plane. The data consist of pressure spectral distributions at five positions within the system and 2D flowfield information measured by Particle Imaging Velocimetry (PIV). The results show that acoustic oscillations increase with U{sub 0} and {phi}. However, the levels in the 90% H{sub 2} flames are significantly higher than in the CH{sub 4} flames. For both fuels, the use of the quarl reduces the fluctuating pressures in the combustion chamber by up to a factor of 7. The PIV results suggest this to be a consequence of the quarl restricting the formation of large vortices in the outer shear layer. A Generalized Instability Model (GIM) was applied to analyze the acoustic response of baseline flames for each of the two fuels. The measured frequencies and the stability trends for these two cases are predicted and the triggered acoustic mode shapes identified.

  4. Iodine stress corrosion cracking of Zircaloy: Laboratory data, a phenomenological model, and predictions of in-reactor behavior

    International Nuclear Information System (INIS)

    Miller, A.K.; Tasooji, A.

    1981-01-01

    Data from laboratory tests performed on unirradiated and irradiated Zircaloy have been used as the basis for developing a phenomenological model of iodine-induced stress corrosion crack initiation and growth. The model is capable of predicting the response of cladding subjected to complex loading conditions. Major features of the data incorporated into the model include the existence of a threshold stress, the effect of iodine concentration, temperature effects, the role of chemical inhomogeneities and mechanical flaws, crack initiation in smooth specimens, crack propagation rates as a function of stress intensity in flawed specimens, and the detrimental effect of irradiation. The major physical processes addressed by the model include intergranular stress corrosion cracking (SCC), transgranular SCC, ductile rupture, iodine penetration by surface diffusion along existing on incipient cracks, and stress and strain intensification and triaxiality caused by cracks or flaws. A probabilistic description of the size distribution of the flaws found in as-fabricated cladding is used at the basis for quantitatively extrapolating the laboratory test results to predict in-reactor cladding behavior. The in-reactor SCC resistance of a large fuel assembly is predicted to be substantially lower and more variable than that of small laboratory specimens. (orig.)

  5. Bioassay Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Bioassay Laboratory is an accredited laboratory capable of conducting standardized and innovative environmental testing in the area of aquatic ecotoxicology. The...

  6. HYDROMECHANICS LABORATORY

    Data.gov (United States)

    Federal Laboratory Consortium — Naval Academy Hydromechanics LaboratoryThe Naval Academy Hydromechanics Laboratory (NAHL) began operations in Rickover Hall in September 1976. The primary purpose of...

  7. TWODEE: the Health and Safety Laboratory's shallow layer model for heavy gas dispersion. Part 1. Mathematical basis and physical assumptions.

    Science.gov (United States)

    Hankin, R K; Britter, R E

    1999-05-14

    The Major Hazard Assessment Unit of the Health and Safety Executive (HSE) provides advice to local planning authorities on land use planning in the vicinity of major hazard sites. For sites with the potential for large scale releases of toxic heavy gases such as chlorine this advice is based on risk levels and is informed by use of the computerised risk assessment tool RISKAT [C. Nussey, M. Pantony, R. Smallwood, HSE's risk assessment tool RISKAT, Major Hazards: Onshore and Offshore, October, 1992]. At present RISKAT uses consequence models for heavy gas dispersion that assume flat terrain. This paper is the first part of a three part paper. Part 1 describes the mathematical basis of TWODEE, the Health and Safety Laboratory's shallow layer model for heavy gas dispersion. The shallow layer approach used by TWODEE is a compromise between the complexity of CFD models and the simpler integral models. Motivated by the low aspect ratio of typical heavy gas clouds, shallow layer models use depth-averaged variables to describe the flow behaviour. This approach is particularly well suited to assess the effect of complex terrain because the downslope buoyancy force is easily included. Entrainment may be incorporated into a shallow layer model by the use of empirical formulae. Part 2 of this paper presents the numerical scheme used to solve the TWODEE mathematical model, and validated against theoretical results. Part 3 compares the results of the TWODEE model with the experimental results taken at Thorney Island [J. McQuaid, B. Roebuck, The dispersion of heavier-than-air gas from a fenced enclosure. Final report to the US Coast Guard on contract with the Health and Safety Executive, Technical Report RPG 1185, Safety Engineering Laboratory, Research and Laboratory Services Division, Broad Lane, Sheffield S3 7HQ, UK, 1985]. Crown Copyright Copyright 1999 Published by Elsevier Science B.V.

  8. Effects of spray angle variation on mixing in a cold supersonic combustor with kerosene fuel

    Science.gov (United States)

    Zhu, Lin; Luo, Feng; Qi, Yin-Yin; Wei, Min; Ge, Jia-Ru; Liu, Wei-Lai; Li, Guo-Li; Jen, Tien-Chien

    2018-03-01

    Effective fuel injection and mixing is of particular importance for scramjet engines to be operated reliably because the fuel must be injected into high-speed crossflow and mixed with the supersonic air at an extremely short time-scale. This study numerically characterizes an injection jet under different spray angles in a cold kerosene-fueled supersonic flow and thus assesses the effects of the spray angle on the mixing between incident shock wave and transverse cavity injection. A detailed computational fluid dynamics model is developed in accordance with the real scramjet combustor. Next, the spray angles are designated as 45°, 90°, and 135° respectively with the other constant operational conditions (such as the injection diameter, velocity and pressure). Next, a combination of a three dimensional Couple Level Set & Volume of Fluids with an improved Kelvin-Helmholtz & Rayleigh-Taylor model is used to investigate the interaction between kerosene and supersonic air. The numerical predictions are focused on penetration depth, span expansion area, angle of shock wave and sauter mean diameter distribution of the kerosene droplets with or without evaporation. Finally, validation has been implemented by comparing the calculated to the measured in literature with good qualitative agreement. Results show that no matter whether the evaporation is considered, the penetration depth, span-wise angle and expansion area of the kerosene droplets are all increased with the spray angle, and most especially, that the size of the kerosene droplets is surely reduced with the spray angle increase. These calculations are beneficial to better understand the underlying atomization mechanism in the cold kerosene-fueled supersonic flow and hence provide insights into scramjet design improvement.

  9. Designing Science Laboratories: Learning Environments, School Architecture and Teaching and Learning Models

    Science.gov (United States)

    Veloso, Luísa; Marques, Joana S.

    2017-01-01

    This article on secondary schools science laboratories in Portugal focuses on how school space functions as a pedagogical and political instrument by contributing to shape the conditions for teaching and learning dynamics. The article places the impact of changes to school layouts within the larger context of a public school renovation programme,…

  10. Small Laccase from "Streptomyces Coelicolor"--An Ideal Model Protein/Enzyme for Undergraduate Laboratory Experience

    Science.gov (United States)

    Cook, Ryan; Hannon, Drew; Southard, Jonathan N.; Majumdar, Sudipta

    2018-01-01

    A one semester undergraduate biochemistry laboratory experience is described for an understanding of recombinant technology from gene cloning to protein characterization. An integrated experimental design includes three sequential modules: molecular cloning, protein expression and purification, and protein analysis and characterization. Students…

  11. Child Development Laboratory Schools as Generators of Knowledge in Early Childhood Education: New Models and Approaches

    Science.gov (United States)

    McBride, Brent A.; Groves, Melissa; Barbour, Nancy; Horm, Diane; Stremmel, Andrew; Lash, Martha; Bersani, Carol; Ratekin, Cynthia; Moran, James; Elicker, James; Toussaint, Susan

    2012-01-01

    Research Findings: University-based child development laboratory programs have a long and rich history of supporting teaching, research, and outreach activities in the child development/early childhood education fields. Although these programs were originally developed in order to conduct research on children and families to inform policy and…

  12. Modeling lung cancer risks in laboratory dogs exposed to inhaled plutonium

    International Nuclear Information System (INIS)

    Gilbert, E.S.; Park, J.F.; Buschbom, R.L.

    1990-06-01

    These analyses are based on data from a lifespan study of beagle dogs exposed to inhaled plutonium being conducted at Pacific Northwest Laboratory. An important goal of this study is to increase understanding of health risk resulting from this exposure, with particular attention to lung cancer risks. Data on humans exposed to plutonium are inadequate for achieving this goal

  13. Laboratory modeling of air-sea interaction under severe wind conditions

    Science.gov (United States)

    Troitskaya, Yuliya; Vasiliy, Kazakov; Nicolay, Bogatov; Olga, Ermakova; Mikhail, Salin; Daniil, Sergeev; Maxim, Vdovin

    2010-05-01

    Wind-wave interaction at extreme wind speed is of special interest now in connection with the problem of explanation of the sea surface drag saturation at the wind speed exceeding 30 m/s. The idea on saturation (and even reduction) of the coefficient of aerodynamic resistance of the sea surface at hurricane wind speed was first suggested by Emanuel (1995) on the basis of theoretical analysis of sensitivity of maximum wind speed in a hurricane to the ratio of the enthalpy and momentum exchange coefficients. Both field (Powell, Vickery, Reinhold, 2003, French et al, 2007, Black, et al, 2007) and laboratory (Donelan et al, 2004) experiments confirmed that at hurricane wind speed the sea surface drag coefficient is significantly reduced in comparison with the parameterization obtained at moderate to strong wind conditions. Two groups of possible theoretical mechanisms for explanation of the effect of the sea surface drag reduction can be specified. In the first group of models developed by Kudryavtsev & Makin (2007) and Kukulka,Hara Belcher (2007), the sea surface drag reduction is explained by peculiarities of the air flow over breaking waves. Another approach more appropriate for the conditions of developed sea exploits the effect of sea drops and sprays on the wind-wave momentum exchange (Andreas, 2004; Makin, 2005; Kudryavtsev, 2006). The main objective of this work is investigation of factors determining momentum exchange under high wind speeds basing on the laboratory experiment in a well controlled environment. The experiments were carried out in the Thermo-Stratified WInd-WAve Tank (TSWIWAT) of the Institute of Applied Physics. The parameters of the facility are as follows: airflow 0 - 25 m/s (equivalent 10-m neutral wind speed U10 up to 60 m/s), dimensions 10m x 0.4m x 0.7 m, temperature stratification of the water layer. Simultaneous measurements of the airflow velocity profiles and wind waves were carried out in the wide range of wind velocities. Airflow

  14. Investigation of Combustion Control in a Dump Combustor Using the Feedback Free Fluidic Oscillator

    Science.gov (United States)

    Meier, Eric J.; Casiano, Matthew J.; Anderson, William E.; Heister, Stephen D.

    2015-01-01

    A feedback free fluidic oscillator was designed and integrated into a single element rocket combustor with the goal of suppressing longitudinal combustion instabilities. The fluidic oscillator uses internal fluid dynamics to create an unsteady outlet jet at a specific frequency. An array of nine fluidic oscillators was tested to mimic modulated secondary oxidizer injection into the combustor dump plane. The combustor has a coaxial injector that uses gaseous methane and decomposed hydrogen peroxide with an overall O/F ratio of 11.7. A sonic choke plate on an actuator arm allows for continuous adjustment of the oxidizer post acoustics enabling the study of a variety of instability magnitudes. The fluidic oscillator unsteady outlet jet performance is compared against equivalent steady jet injection and a baseline design with no secondary oxidizer injection. At the most unstable operating conditions, the unsteady outlet jet saw a 67% reduction in the instability pressure oscillation magnitude when compared to the steady jet and baseline data. Additionally, computational fluid dynamics analysis of the combustor gives insight into the flow field interaction of the fluidic oscillators. The results indicate that open loop high frequency propellant modulation for combustion control can be achieved through fluidic devices that require no moving parts or electrical power to operate.

  15. Experimental evaluation of sorbents for sulfur control in a coal-fueled gas turbine slagging combustor

    International Nuclear Information System (INIS)

    Cowell, L.H.; Wen, C.S.; LeCren, R.T.

    1992-01-01

    This paper reports on a slagging combustor that has been used to evaluate three calcium-based sorbents for sulfur capture efficiency in order to assess their applicability for use in a oil-fueled gas turbine. Testing is competed in a bench-scale combustor with one-tenth the heat input needed for the full-scale gas turbine. The bench-scale rig is a two-stage combustor featuring a fuel-rich primary zone an a fuel-lean secondary zone. The combustor is operated at 6.5 bars with inlet air preheated to 600 K. Gas temperatures of 1840 K are generated in the primary zone and 1280 K in the secondary zone. Sorbents are either fed into the secondary zone or mixed with the coal-water mixture and fed into the primary zone. Dry powered sorbents are fed into the secondary zone by an auger into one of six secondary air inlet ports. The three sorbents tested in the secondary zone include dolomite, pressure-hydrated dolomitic lime, and hydrated lime. Sorbents have been tested while burning coal-water mixtures with coal sulfur loadings of 0.56 to 3.13 weight percent sulfur. Sorbents are injected into the secondary zone at varying flow rates such that the calcium/sulfur ratio varies from 0.5 to 10.0

  16. Experimental and numerical studies of a lean-burn internally-staged combustor

    Directory of Open Access Journals (Sweden)

    Fu Zhenbo

    2014-06-01

    Full Text Available A lean-burn internally-staged combustor for low emissions that can be used in civil aviation gas turbines is introduced in this paper. The main stage is designed and optimized in terms of fuel evaporation ratio, fuel/air pre-mixture uniformity, and particle residence time using commercial computational fluid dynamics (CFD software. A single-module rectangular combustor is adopted in performance tests including lean ignition, lean blowout, combustion efficiency, emissions, and combustion oscillation using aviation kerosene. Furthermore, nitrogen oxides (NOx emission is also predicted using CFD simulation to compare with test results. Under normal inlet temperature, this combustor can be ignited easily with normal and negative inlet pressures. The lean blowout fuel/air ratio (LBO FAR at the idle condition is 0.0049. The fuel split proportions between the pilot and main stages are determined through balancing emissions, combustion efficiency, and combustion oscillation. Within the landing and take-off (LTO cycle, this combustor enables 42% NOx reduction of the standard set by the 6th Committee on Aviation Environmental Protection (CAEP/6 with high combustion efficiency. The maximum board-band pressure oscillations of inlet air and fuel are below 1% of total pressure during steady-state operations at the LTO cycle specific conditions.

  17. Wall heat flux influence on the thermodynamic optimisation of irreversibilities of a circulating fluidised bed combustor

    CSIR Research Space (South Africa)

    Baloyi, J

    2016-07-01

    Full Text Available In the study the comparison of irreversibilities was done when the wall condition of the combustor was changed from adiabatic to negative heat flux, for incoming air temperature of 400 K. The reactant mixture of solid pitch pine wood fuel and air...

  18. EMISSION TEST REPORT- FIELD TEST OF CARBON INJECTION FOR MERCURY CONTROL, CAMDEN COUNTY MUNICIPAL WASTE COMBUSTOR

    Science.gov (United States)

    The report gives results of parametric test to evaluate the injection powdered activated carbon to control volatile pollutants in municipal waste combustor (MWC) flue gas. he tests were conducted at a spray dryer absorber/electrostatic precipitator (SD/ESP)-equipped MWC in Camden...

  19. 3D Measurements of Ignition Processes at 20 kHz in a Supersonic Combustor

    Science.gov (United States)

    2015-03-05

    Wehe, 3D Flame Measurements at 5 kHz on a Jet Fueled Aviation Combustor. ASME Turbo Expo 2015 (2014) 10. M. Kang, Q. Lei, L. Ma, Characterization of...Geipel, A.M. Kempf, Computed tomography of chemiluminescence (CTC): instantaneous 3D measurements and phantom studies of a turbulent opposed jet

  20. Evaluation of fuel injection configurations to control carbon and soot formation in small GT combustors

    Science.gov (United States)

    Rosfjord, T. J.; Briehl, D.

    1982-01-01

    An experimental program to investigate hardware configurations which attempt to minimize carbon formation and soot production without sacrificing performance in small gas turbine combustors has been conducted at the United Technologies Research Center. Four fuel injectors, embodying either airblast atomization, pressure atomization, or fuel vaporization techniques, were combined with nozzle air swirlers and injector sheaths, and evaluated at test conditions which included and extended beyond standard small gas turbine combustor operation. Extensive testing was accomplished with configurations embodying either a spill return or a T-vaporizer injector. Minimal carbon deposits were observed on the spill return nozzle for tests using either Jet A or ERBS test fuel. A more extensive film of soft carbon was observed on the vaporizer after operation at standard engine conditions, with large carbonaceous growths forming on the device during off-design operation at low combustor inlet temperature. Test results indicated that smoke emission levels depended on the combustor fluid mechanics (especially the mixing rates near the injector), the atomization quality of the injector and the fuel hydrogen content.

  1. Simulation Investigation on Combustion Characteristics in a Four-Point Lean Direct Injection Combustor with Hydrogen/Air

    Directory of Open Access Journals (Sweden)

    Jianzhong Li

    2017-06-01

    Full Text Available To investigate the combustion characteristics in multi-point lean direct injection (LDI combustors with hydrogen/air, two swirl–venturi 2 × 2 array four-point LDI combustors were designed. The four-point LDI combustor consists of injector assembly, swirl–venturi array and combustion chamber. The injector, swirler and venturi together govern the rapid mixing of hydrogen and air to form the mixture for combustion. Using clockwise swirlers and anticlockwise swirlers, the co-swirling and count-swirling swirler arrays LDI combustors were achieved. Using Reynolds-Averaged Navier–Stokes (RANS code for steady-state reacting flow computations, the four-point LDI combustors with hydrogen/air were simulated with an 11 species and 23 lumped reaction steps H2/Air reaction mechanism. The axial velocity, turbulence kinetic energy, total pressure drop coefficient, outlet temperature, mass fraction of OH and emission of pollutant NO of four-point LDI combustors, with different equivalence ratios, are here presented and discussed. As the equivalence ratios increased, the total pressure drop coefficient became higher because of increasing heat loss. Increasing equivalence ratios also corresponded with the rise in outlet temperature of the four-point LDI combustors, as well as an increase in the emission index of NO EINO in the four-point LDI combustors. Along the axial distance, the EINO always increased and was at maximum at the exit of the dump. Along the chamber, the EINO gradually increased, maximizing at the exit of chamber. The total temperature of four-point LDI combustors with different equivalence ratios was identical to the theoretical equilibrium temperature. The EINO was an exponential function of the equivalence ratio.

  2. Air Flow Modeling in the Wind Tunnel of the FHWA Aerodynamics Laboratory at Turner-Fairbank Highway Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Transportation Research and Analysis Computing Center (TRACC) Energy Systems Division; Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Transportation Research and Analysis Computing Center (TRACC) Energy Systems Division; Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States). Transportation Research and Analysis Computing Center (TRACC) Energy Systems Division

    2017-09-01

    Computational fluid dynamics (CFD) modeling is widely used in industry for design and in the research community to support, compliment, and extend the scope of experimental studies. Analysis of transportation infrastructure using high performance cluster computing with CFD and structural mechanics software is done at the Transportation Research and Analysis Computing Center (TRACC) at Argonne National Laboratory. These resources, available at TRACC, were used to perform advanced three-dimensional computational simulations of the wind tunnel laboratory at the Turner-Fairbank Highway Research Center (TFHRC). The goals were to verify the CFD model of the laboratory wind tunnel and then to use versions of the model to provide the capability to (1) perform larger parametric series of tests than can be easily done in the laboratory with available budget and time, (2) to extend testing to wind speeds that cannot be achieved in the laboratory, and (3) to run types of tests that are very difficult or impossible to run in the laboratory. Modern CFD software has many physics models and domain meshing options. Models, including the choice of turbulence and other physics models and settings, the computational mesh, and the solver settings, need to be validated against measurements to verify that the results are sufficiently accurate for use in engineering applications. The wind tunnel model was built and tested, by comparing to experimental measurements, to provide a valuable tool to perform these types of studies in the future as a complement and extension to TFHRC’s experimental capabilities. Wind tunnel testing at TFHRC is conducted in a subsonic open-jet wind tunnel with a 1.83 m (6 foot) by 1.83 m (6 foot) cross section. A three component dual force-balance system is used to measure forces acting on tested models, and a three degree of freedom suspension system is used for dynamic response tests. Pictures of the room are shown in Figure 1-1 to Figure 1-4. A detailed CAD

  3. Advanced combustor design concept to control NOx and air toxics

    Energy Technology Data Exchange (ETDEWEB)

    Eddings, E.G.; Pershing, D.W.; Molina, A.; Sarofim, A.F.; Spinti, J.P.; Veranth, J.

    1999-03-29

    Direct coal combustion needs to be a primary energy source for the electric utility industry and for heavy manufacturing during the next several decades because of the availability and economic advantage of coal relative to other fuels and because of the time required to produce major market penetration in the energy field. However, the major obstacle to coal utilization is a set of ever-tightening environmental regulations at both the federal and local level. It is, therefore, critical that fundamental research be conducted to support the development of low-emission, high-efficiency pulverized coal power systems. The objective of this program was to develop fundamental understanding regarding the impact of fuel and combustion changes on NOx formation, carbon burnout and air toxic emissions from pulverized coal (pc) combustion. During pc combustion, nitrogen in the coal can be oxidized to form nitrogen oxides (NO{sub x}). The 1990 Clean Air Act Amendments established much stricter NO{sub x} emissions limits for new and existing coal-fired plants, so there has been renewed interest in the processes by which NO{sub x} forms in pc flames. One of the least understood aspects of NO{sub x} formation from pc combustion is the process by which char-N (nitrogen remaining in the char after devolatilization) forms either NO{sub x} or N{sub 2}, and the development of a fundamental understanding of this process was a major focus of this research. The overall objective of this program was to improve the ability of combustion system designers and boiler manufacturers to build high efficiency, low emission pulverized coal systems by improving the design tools available to the industry. The specific program goals were to: Use laboratory experiments and modeling to develop fundamental understanding for a new submodel for char nitrogen oxidation (a critical piece usually neglected in most NOx models.); Use existing bench scale facilities to investigate alternative schemes to

  4. The development of an aquatic spill model for the White Oak Creek watershed, Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.O.

    1996-05-01

    This study develops an aquatic spill model applicable to the White Oak Creek watershed draining the Oak Ridge National Laboratory. Hazardous, toxic, and radioactive chemicals are handled and stored on the laboratory reservation. An accidental spill into the White Oak Creek watershed could contaminate downstream water supplies if insufficient dilution did not occur. White Oak Creek empties into the Clinch River, which flows into the Tennessee River. Both rivers serve as municipal water supplies. The aquatic spill model provides estimates of the dilution at sequential downstream locations along White Oak creek and the Clinch River after an accidental spill of a liquid containing a radioactively decaying constituent. The location of the spill on the laboratory is arbitrary, while hydrologic conditions range from drought to extreme flood are simulated. The aquatic spill model provides quantitative estimates with which to assess water quality downstream from the site of the accidental spill, allowing an informed decision to be made whether to perform mitigating measures so that the integrity of affected water supplies is not jeopardized.

  5. Improvement in laboratory test turnaround times for inpatients following move to hub and spoke model of delivery

    Directory of Open Access Journals (Sweden)

    David James

    2015-04-01

    Full Text Available Objectives: The relative merits of hub and spoke models of service delivery are often debated, but accessing data on how they may benefit service delivery can be difficult, and may hinder the adoption of a model which can benefit the health community. Our aim was to provide objective data that would either support or refute one potential benefit of service redesign, namely the effect on turnaround times within the acute hospital. Design and methods: Data on turnaround times for sequential requests containing creatinine as a request item received from inpatient locations at two acute hospitals were extracted from the laboratory computer system. Monthly data was collected for a period of 5 months prior to and the same 5 month period following the service redesign. Data was subjected to statistical process control (SPC analysis. Results: There was a statistically significant reduction (P<0.05 in the average turnaround time of at least 29% for routine requests and 22% for urgent requests, accompanied by a statistically significant reduction (P<0.05 in upper control limits of least 46% – improving the predictability of result availability and reducing the 95% confidence interval for turnaround times. Conclusions: Adoption of a “hub and spoke” model has the potential to support laboratories in improving both urgent and non-urgent turnaround times in a cost-efficient manner within acute hospitals, and reduce the variability in turnaround time. Keywords: Laboratory organisation, Turnaround time, Efficiency

  6. Laboratory-based surveillance in the molecular era: the TYPENED model, a joint data-sharing platform for clinical and public health laboratories.

    Science.gov (United States)

    Niesters, H G; Rossen, J W; van der Avoort, H; Baas, D; Benschop, K; Claas, E C; Kroneman, A; van Maarseveen, N; Pas, S; van Pelt, W; Rahamat-Langendoen, J C; Schuurman, R; Vennema, H; Verhoef, L; Wolthers, K; Koopmans, M

    2013-01-24

    Laboratory-based surveillance, one of the pillars of monitoring infectious disease trends, relies on data produced in clinical and/or public health laboratories. Currently, diagnostic laboratories worldwide submit strains or samples to a relatively small number of reference laboratories for characterisation and typing. However, with the introduction of molecular diagnostic methods and sequencing in most of the larger diagnostic and university hospital centres in high-income countries, the distinction between diagnostic and reference/public health laboratory functions has become less clear-cut. Given these developments, new ways of networking and data sharing are needed. Assuming that clinical and public health laboratories may be able to use the same data for their own purposes when sequence-based testing and typing are used, we explored ways to develop a collaborative approach and a jointly owned database (TYPENED) in the Netherlands. The rationale was that sequence data - whether produced to support clinical care or for surveillance -can be aggregated to meet both needs. Here we describe the development of the TYPENED approach and supporting infrastructure, and the implementation of a pilot laboratory network sharing enterovirus sequences and metadata.

  7. Quantification of Uncertainty in Mathematical Models: The Statistical Relationship between Field and Laboratory pH Measurements

    Directory of Open Access Journals (Sweden)

    Kurt K. Benke

    2017-01-01

    Full Text Available The measurement of soil pH using a field portable test kit represents a fast and inexpensive method to assess pH. Field based pH methods have been used extensively for agricultural advisory services and soil survey and now for citizen soil science projects. In the absence of laboratory measurements, there is a practical need to model the laboratory pH as a function of the field pH to increase the density of data for soil research studies and Digital Soil Mapping. The accuracy and uncertainty in pH field measurements were investigated for soil samples from regional Victoria in Australia using both linear and sigmoidal models. For samples in water and CaCl2 at 1 : 5 dilutions, sigmoidal models provided improved accuracy over the full range of field pH values in comparison to linear models (i.e., pH 9. The uncertainty in the field results was quantified by the 95% confidence interval (CI and 95% prediction interval (PI for the models, with 95% CI < 0.25 pH units and 95% PI = ±1.3 pH units, respectively. It was found that the Pearson criterion for robust regression analysis can be considered as an alternative to the orthodox least-squares modelling approach because it is more effective in addressing outliers in legacy data.

  8. Thermal characteristics of various biomass fuels in a small-scale biomass combustor

    International Nuclear Information System (INIS)

    Al-Shemmeri, T.T.; Yedla, R.; Wardle, D.

    2015-01-01

    Biomass combustion is a mature and reliable technology, which has been used for heating and cooking. In the UK, biomass currently qualifies for financial incentives such as the Renewable Heat Incentive (RHI). Therefore, it is vital to select the right type of fuel for a small-scale combustor to address different types of heat energy needs. In this paper, the authors attempt to investigate the performance of a small-scale biomass combustor for heating, and the impact of burning different biomass fuels on useful output energy from the combustor. The test results of moisture content, calorific value and combustion products of various biomass samples were presented. Results from this study are in general agreement with published data as far as the calorific values and moisture contents are concerned. Six commonly available biomass fuels were tested in a small-scale combustion system, and the factors that affect the performance of the system were analysed. In addition, the study has extended to examine the magnitude and proportion of useful heat, dissipated by convection and radiation while burning different biomass fuels in the small-scale combustor. It is concluded that some crucial factors have to be carefully considered before selecting biomass fuels for any particular heating application. - Highlights: • Six biomass materials combustion performance in a small combustor was examined. • Fuel combustion rate and amount of heat release has varied between materials. • Heat release by radiation, convection and flue gasses varied between materials. • Study helps engineers and users of biomass systems to select right materials

  9. Anesthesia in swine : optimizing a laboratory model to optimize translational research.

    Science.gov (United States)

    Pehböck, D; Dietrich, H; Klima, G; Paal, P; Lindner, K H; Wenzel, V

    2015-01-01

    In order to extrapolate novel therapies from the bench to the bedside (translational research), animal experiments are scientifically necessary. Swine are popular laboratory animals as their cardiorespiratory physiology is very similar to humans. Every study has to be approved by the local and/or national animal ethical committees. As swine are extremely sensitive to stress the primary goal is therefore to provide a calm, stress-free environment in both housing and experimental facilities. Swine should be properly sedated for transport and normothermia needs to be ensured. It is recommended to commence anesthesia by injecting ketamine and propofol followed by endotracheal intubation during spontaneous breathing. After intubation, anesthesia maintenance is performed with morphine or piritramide, propofol and rocuronium and routine monitoring is applied analogue to a clinical operating theater for humans. Normothermia (38.5 °C) needs to be ensured. While surgical procedures can be readily extrapolated from a human operating theater to swine, non-anesthesiologist scientists may lose the animal rapidly due to airway management problems. Vascular access can be secured by cut-downs or ultrasound-guided techniques in the inguinal and the neck region. For humane euthanasia of pigs, morphine, followed by propofol, rocuronium and potassium chloride are recommended. As radical animal right groups may threaten scientists, it is prudent that animal laboratories have unmarked entrance doors, are located in buildings that are not accessible to the public and strictly controlled access of laboratory staff is enforced. In conclusion, swine are an excellent laboratory animal for bench to bedside research and can be managed properly when basic knowledge and adequate skills on careful handling, anesthesia and surgical considerations are present.

  10. Evaluation of Porosity and Saturation Degree by Laboratory Joint Measurements of Velocity and Resistivity: A Model Improvement

    Science.gov (United States)

    Carrara, E.; Mazzacca, A.; Pece, R.; Roberti, N.; Vanorio, T.

    This paper illustrates the laboratory procedures and experiments carried out on samples with different lithologies and reconstructed samples in order to test and implement an electroseismic model (Carrara et al., 1994) which allows the evaluation of porosity and the saturation degree of rocks. The testing was conducted by comparing porosity (Φ) and saturation degree (Sw ) values, obtained from measured resistivity (ρ) and elastic wave velocity (VP ) by means of appropriate formulations, with the values of Φ and Sw previously calculated by geotechnics and employed as standards. The experimental results have led to a good definition of the model to be proposed as an application method in the field of hydrogeology.

  11. Anatomical features for an adequate choice of experimental animal model in biomedicine: II. Small laboratory rodents, rabbit, and pig.

    Science.gov (United States)

    Lossi, Laura; D'Angelo, Livia; De Girolamo, Paolo; Merighi, Adalberto

    2016-03-01

    The anatomical features distinctive to each of the very large array of species used in today's biomedical research must be born in mind when considering the correct choice of animal model(s), particularly when translational research is concerned. In this paper we take into consideration and discuss the most important anatomical and histological features of the commonest species of laboratory rodents (rat, mouse, guinea pig, hamster, and gerbil), rabbit, and pig related to their importance for applied research. Copyright © 2015 Elsevier GmbH. All rights reserved.

  12. Applications of Mars Global Reference Atmospheric Model (Mars-GRAM 2005) Supporting Mission Site Selection for Mars Science Laboratory

    Science.gov (United States)

    Justh, Hilary L.; Justus, Carl G.

    2008-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM 2005) is an engineering level atmospheric model widely used for diverse mission applications. An overview is presented of Mars-GRAM 2005 and its new features. One new feature of Mars-GRAM 2005 is the 'auxiliary profile' option. In this option, an input file of temperature and density versus altitude is used to replace mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. An auxiliary profile can be generated from any source of data or alternate model output. Auxiliary profiles for this study were produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5)model) and a global Thermal Emission Spectrometer(TES) database. The global TES database has been specifically generated for purposes of making Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components,averaged over 5-by-5 degree latitude-longitude bins and 15 degree L(s) bins, for each of three Mars years of TES nadir data. Results are presented using auxiliary profiles produced from the mesoscale model output and TES observed data for candidate Mars Science Laboratory (MSL) landing sites. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

  13. Specialist integrated haematological malignancy diagnostic services: an Activity Based Cost (ABC) analysis of a networked laboratory service model.

    Science.gov (United States)

    Dalley, C; Basarir, H; Wright, J G; Fernando, M; Pearson, D; Ward, S E; Thokula, P; Krishnankutty, A; Wilson, G; Dalton, A; Talley, P; Barnett, D; Hughes, D; Porter, N R; Reilly, J T; Snowden, J A

    2015-04-01

    Specialist Integrated Haematological Malignancy Diagnostic Services (SIHMDS) were introduced as a standard of care within the UK National Health Service to reduce diagnostic error and improve clinical outcomes. Two broad models of service delivery have become established: 'co-located' services operating from a single-site and 'networked' services, with geographically separated laboratories linked by common management and information systems. Detailed systematic cost analysis has never been published on any established SIHMDS model. We used Activity Based Costing (ABC) to construct a cost model for our regional 'networked' SIHMDS covering a two-million population based on activity in 2011. Overall estimated annual running costs were £1 056 260 per annum (£733 400 excluding consultant costs), with individual running costs for diagnosis, staging, disease monitoring and end of treatment assessment components of £723 138, £55 302, £184 152 and £94 134 per annum, respectively. The cost distribution by department was 28.5% for haematology, 29.5% for histopathology and 42% for genetics laboratories. Costs of the diagnostic pathways varied considerably; pathways for myelodysplastic syndromes and lymphoma were the most expensive and the pathways for essential thrombocythaemia and polycythaemia vera being the least. ABC analysis enables estimation of running costs of a SIHMDS model comprised of 'networked' laboratories. Similar cost analyses for other SIHMDS models covering varying populations are warranted to optimise quality and cost-effectiveness in delivery of modern haemato-oncology diagnostic services in the UK as well as internationally. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. Laboratory model of the potential role of fungi (Phytophthora spp. ) in the decomposition of red mangrove (Rhizophora mangle) leaf litter

    Energy Technology Data Exchange (ETDEWEB)

    Fell, J.W.; Master, I.M.; Newell, S.Y.

    1977-01-01

    Field studies of quantitative changes in carbon, nitrogen and dry weight of decomposing mangrove leaves demonstrated similar net weight and carbon losses irrespective of station location or time of year. In contrast, rates differed and percent change in nitrogen content varied from no gain to 78% increase. A laboratory model was designed to examine the field responses. Because of variation between leaves, a split leaf technique was developed in which one half of the leaf was used to predict the original carbon, nitrogen and dry weight of the other, experimental, half leaf. Nitrogen immobilization, in the laboratory studies, required the presence of microorganisms, such as fungi of the genus Phytophthora, and the addition of inorganic N. The final amount of nitrogen in the leaf was directly related to the original amount, however, change in nitrogen was inversely related to original nitrogen. Weight loss was inversely related to the dry weight:fresh weight ratio of the leaves, possibly due to the high fiber content of the high ratio leaves. A discussion is presented of the field results, as interpreted by the laboratory model. 28 references, 15 figures, 1 table.

  15. Development of a pulsed coal combustor fired with CWM (coal-water mixture): Phase 3, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, M.N.; Durai-Swamy, K.

    1986-11-01

    This report presents the results of an R and D program aimed at developing a new burner technology for coal-water mixture (CWM) fuels to enable the substitution of these new fuels in utility and industrial boilers and process heaters currently firing oil and gas. The application of pulse combustion to CWM fuels is chosen to alleviate many of the physical plant and environmental constraints presently associated with the direct use of these fuels in equipment designed for oil and gas firing. Pulse combustion has been shown to be capable of high-intensity burning of coal for acceptably complete combustion within relatively small equipment volumes. It also has the inherent capability to agglomerate ash particles, thus rendering ash more easily separable from the combustion gas prior to its entrance into the convective section of the boiler or heater, thereby reducing ash buildup and pluggage. Pulse combustion is also well-suited to staged combustion for NO/sub x/ control and has excellent potential for enhanced in-furnace SO/sub 2/ removal due to the enhanced levels of mass transfer brought about by the vigorous flow oscillations. The primary objective of the Phase 2 work was to develop a detailed program for laboratory development and evaluation of the pulse CWM combustor and system design concepts. 112 refs., 40 figs., 94 tabs.

  16. Visualization and Analysis of a Hydrocarbon Premixed Flame a in Small Scale Scramjet Combustor

    Science.gov (United States)

    Cantu, Luca Maria Luigi

    Nitric oxide (NO) planar induced laser fluorescence (PLIF) measurements have been performed in a small scale scramjet combustor at the University of Virginia Aerospace Research Laboratory at nominal simulated Mach 5 flight enthalpy. A mixture of NO and N2 was injected at the upstream end of the inlet isolator as a surrogate for ethylene fuel, and the mixing of this fuel simulant was studied with and without a shock train. The shock train was produced by an air throttle, which simulated the blockage effects of combustion downstream of the cavity flame holder. NO PLIF signal was imaged in a plane orthogonal to the freestream at the leading edge of the cavity. Instantaneous planar images were recorded and analyzed to identify the most uniform cases, which were achieved by varying the location of the fuel injection and shock train. This method was used to screen different possible fueling configurations to provide optimized test conditions for follow-on combustion measurements using ethylene fuel. A theoretical study of the selected NO rotational transitions was performed to obtain a LIF signal that is linear with NO mole fraction and approximately independent of pressure and temperature. In the same facility, OH PLIF measurements were also performed; OH lines were carefully chosen to have fluorescent signal that is independent of pressure and temperature but linear with mole fraction. The OH PLIF signal was imaged in planes orthogonal to and parallel to the freestream flow at different equivalence ratios. Flameout limits were tested and identified. Instantaneous planar images were recorded and analyzed to compare the results with width increased dual-pump enhanced coherent anti-Stokes Raman spectroscopy (WIDECARS) measurements in the same facility and large eddy simulation/Reynolds average Navier-Stokes (LES/RANS) numerical simulations. The flame angle was found to be approximately 10 degrees for several different conditions, which is in agreement with numerical

  17. LiLa Booking System: Architecture and Conceptual Model of a Rig Booking System for On-Line Laboratories

    Directory of Open Access Journals (Sweden)

    Dr. Víctor A. Villagrá

    2011-11-01

    Full Text Available Many educational institutions acknowledged the importance of providing online-access to student laboratories. To optimize the use of the scarce and expensive resources such laboratories depend on, it is advisable to establish and setup a booking system that helps to administer access to them. This paper reports on the architecture and conceptual model of the rig booking system designed for the LiLa Portal, a web portal that makes virtual and remote experiments available on the Internet. The design of the booking system is based on a requirements analysis carried out by the EC funded LiLa project in cooperation with international partners from the Global Online Lab Consortium, GoLC.

  18. Student Teachers' Modeling of Acceleration Using a Video-Based Laboratory in Physics Education: A Multimodal Case Study

    Directory of Open Access Journals (Sweden)

    Louis Trudel

    2016-06-01

    Full Text Available This exploratory study intends to model kinematics learning of a pair of student teachers when exposed to prescribed teaching strategies in a video-based laboratory. Two student teachers were chosen from the Francophone B.Ed. program of the Faculty of Education of a Canadian university. The study method consisted of having the participants interact with a video-based laboratory to complete two activities for learning properties of acceleration in rectilinear motion. Time limits were placed on the learning activities during which the researcher collected detailed multimodal information from the student teachers' answers to questions, the graphs they produced from experimental data, and the videos taken during the learning sessions. As a result, we describe the learning approach each one followed, the evidence of conceptual change and the difficulties they face in tackling various aspects of the accelerated motion. We then specify advantages and limits of our research and propose recommendations for further study.

  19. Laboratory modeling, field study, and numerical simulation of bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    Livingston, R.J.; Islam, M.R.

    1999-01-01

    Historical methods of cleaning up petroleum hydrocarbons from the vadose zone, the capillary zone, and the aquifers are not technically true cleanup technologies but rather transfer techniques. In addition, environmental engineers are realizing that the standard remediation techniques are not entirely effective in removing the hazardous material in a reasonable time frame. Long-chain hydrocarbons such as kerosene, diesel, and waste oil are particularly difficult to remediate using conventional techniques. The use of bioremediation as an alternative remediation technology is fast becoming the technique of choice among many environmental professionals. This method offers substantial benefits not found in other remediation processes. Bioremediation is very cost effective, nondestructive, relatively uncomplicated in implementing, requires non specialized equipment, and can be extremely effective in removing recalcitrant petroleum hydrocarbons. This study researched the availability of viable microbial populations in the arid climate in South Dakota. Exponential growth of the bacteria and the ability of bacteria to degrade long-chain hydrocarbons indicated that healthy populations do exist and could be used to mineralize organic hydrocarbons. Experimental results indicated that bioremediation can be effectively enhanced in landfills as well as in the subsurface using a supply of harmless nutrients. The biodegradation rate can be further enhanced with the use of edible surfactant that helped disperse the petroleum products. Also, the use of hydrogen peroxide enhanced the oxygen availability and increased the degradation rate. Interestingly, the bacterial growth rate is found to be high in difficult-to-biodegrade contaminants, such as waste oil. A numerical simulation program was also developed that describes the bacterial growth in the subsurface along with the reduction in substrate (contamination). Results from this program were found to be consistent with laboratory

  20. Groundwater Pathway Model for the Los Alamos National Laboratory Technical Area 21, Material Disposal Area T

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Levitt, Daniel G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Miller, Terry Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jordan, Amy [Neptune Inc, Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dash, Zora [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-09

    This report consists of four major sections, including this introductory section. Section 2 provides an overview of previous investigations related to the development of the current sitescale model. The methods and data used to develop the 3-D groundwater model and the techniques used to distill that model into a form suitable for use in the GoldSim models are discussed in Section 3. Section 4 presents the results of the model development effort and discusses some of the uncertainties involved. Three attachments that provide details about the components and data used in this groundwater pathway model are also included with this report.

  1. Models for the field-based toxicity of copper and zinc salts to wheat in 11 Australian soils and comparison to laboratory-based models

    International Nuclear Information System (INIS)

    Warne, Michael St.J.; Heemsbergen, Diane; McLaughlin, Mike; Bell, Mike; Broos, Kris; Whatmuff, Mark; Barry, Glenn; Nash, David; Pritchard, Deb; Penney, Nancy

    2008-01-01

    Laboratory-based relationships that model the phytotoxicity of metals using soil properties have been developed. This paper presents the first field-based phytotoxicity relationships. Wheat (Triticum aestivum L.) was grown at 11 Australian field sites at which soil was spiked with copper (Cu) and zinc (Zn) salts. Toxicity was measured as inhibition of plant growth at 8 weeks and grain yield at harvest. The added Cu and Zn EC10 values for both endpoints ranged from approximately 3 to 4760 mg/kg. There were no relationships between field-based 8-week biomass and grain yield toxicity values for either metal. Cu toxicity was best modelled using pH and organic carbon content while Zn toxicity was best modelled using pH and the cation exchange capacity. The best relationships estimated toxicity within a factor of two of measured values. Laboratory-based phytotoxicity relationships could not accurately predict field-based phytotoxicity responses. - Field-based toxicity of Cu and Zn to wheat can be modelled using soil properties. Laboratory-based models should not be used to estimate toxicity in the field

  2. Modeling chemical systems using cellular automata a textbook and laboratory manual

    CERN Document Server

    Kier, Lemont B; Cheng, Chao-Kun

    2005-01-01

    There are few publications on Cellular Automata and certainly no direct competition Insight into a new modeling paradigm Novel approach to the use of in silico modeling to replace or supplement costly labs.

  3. Diode Laser Sensor for Gas Temperature and H2O Concentration in a Scramjet Combustor Using Wavelength Modulation Spectroscopy (Postprint)

    National Research Council Canada - National Science Library

    Rieker, Gregory B; Li, Jonathan T; Jeffries, Jay B; Mathur, Tarun; Gruber, Mark R; Carter, Campbell D

    2005-01-01

    A diode laser absorption sensor which probes three spectral features of water vapor in the near infrared region to infer gas temperature and water vapor concentration near the exit of a scramjet combustor is presented...

  4. Laboratory Studies of the Reactive Chemistry and Changing CCN Properties of Secondary Organic Aerosol, Including Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Scot Martin

    2013-01-31

    The chemical evolution of secondary-organic-aerosol (SOA) particles and how this evolution alters their cloud-nucleating properties were studied. Simplified forms of full Koehler theory were targeted, specifically forms that contain only those aspects essential to describing the laboratory observations, because of the requirement to minimize computational burden for use in integrated climate and chemistry models. The associated data analysis and interpretation have therefore focused on model development in the framework of modified kappa-Koehler theory. Kappa is a single parameter describing effective hygroscopicity, grouping together several separate physicochemical parameters (e.g., molar volume, surface tension, and van't Hoff factor) that otherwise must be tracked and evaluated in an iterative full-Koehler equation in a large-scale model. A major finding of the project was that secondary organic materials produced by the oxidation of a range of biogenic volatile organic compounds for diverse conditions have kappa values bracketed in the range of 0.10 +/- 0.05. In these same experiments, somewhat incongruently there was significant chemical variation in the secondary organic material, especially oxidation state, as was indicated by changes in the particle mass spectra. Taken together, these findings then support the use of kappa as a simplified yet accurate general parameter to represent the CCN activation of secondary organic material in large-scale atmospheric and climate models, thereby greatly reducing the computational burden while simultaneously including the most recent mechanistic findings of laboratory studies.

  5. Understanding water uptake in bioaerosols using laboratory measurements, field tests, and modeling

    Science.gov (United States)

    Chaudhry, Zahra; Ratnesar-Shumate, Shanna A.; Buckley, Thomas J.; Kalter, Jeffrey M.; Gilberry, Jerome U.; Eshbaugh, Jonathan P.; Corson, Elizabeth C.; Santarpia, Joshua L.; Carter, Christopher C.

    2013-05-01

    Uptake of water by biological aerosols can impact their physical and chemical characteristics. The water content in a bioaerosol can affect the backscatter cross-section as measured by LIDAR systems. Better understanding of the water content in controlled-release clouds of bioaerosols can aid in the development of improved standoff detection systems. This study includes three methods to improve understanding of how bioaerosols take up water. The laboratory method measures hygroscopic growth of biological material after it is aerosolized and dried. Hygroscopicity curves are created as the humidity is increased in small increments to observe the deliquescence point, then the humidity is decreased to observe the efflorescence point. The field component of the study measures particle size distributions of biological material disseminated into a large humidified chamber. Measurements are made with a Twin-Aerodynamic Particle Sizer (APS, TSI, Inc), -Relative Humidity apparatus where two APS units measure the same aerosol cloud side-by-side. The first operated under dry conditions by sampling downstream of desiccant dryers, the second operated under ambient conditions. Relative humidity was measured within the sampling systems to determine the difference in the aerosol water content between the two sampling trains. The water content of the bioaerosols was calculated from the twin APS units following Khlystov et al. 2005 [1]. Biological material is measured dried and wet and compared to laboratory curves of the same material. Lastly, theoretical curves are constructed from literature values for components of the bioaerosol material.

  6. Communication and computing technology in biocontainment laboratories using the NEIDL as a model.

    Science.gov (United States)

    McCall, John; Hardcastle, Kath

    2014-07-01

    The National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, is a globally unique biocontainment research facility housing biosafety level 2 (BSL-2), BSL-3, and BSL-4 laboratories. Located in the BioSquare area at the University's Medical Campus, it is part of a national network of secure facilities constructed to study infectious diseases of major public health concern. The NEIDL allows for basic, translational, and clinical phases of research to be carried out in a single facility with the overall goal of accelerating understanding, treatment, and prevention of infectious diseases. The NEIDL will also act as a center of excellence providing training and education in all aspects of biocontainment research. Within every detail of NEIDL operations is a primary emphasis on safety and security. The ultramodern NEIDL has required a new approach to communications technology solutions in order to ensure safety and security and meet the needs of investigators working in this complex building. This article discusses the implementation of secure wireless networks and private cloud computing to promote operational efficiency, biosecurity, and biosafety with additional energy-saving advantages. The utilization of a dedicated data center, virtualized servers, virtualized desktop integration, multichannel secure wireless networks, and a NEIDL-dedicated Voice over Internet Protocol (VoIP) network are all discussed. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  7. Groundwater Pathway Model for the Los Alamos National Laboratory Technical Area 54, Area G, Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Miller, Terry A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Strobridge, Daniel M. [Neptune Inc., Los Alamos, NM (United States); Cole, Gregory L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Birdsell, Kay H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Robinson, Bruce Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gable, Carl Walter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Broxton, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Springer, Everett P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schofield, Tracy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-10

    This report consists of four major sections, including this introductory section. Section 2 provides an overview of previous investigations related to the development of the current sitescale model. The methods and data used to develop the 3-D groundwater model and the techniques used to distill that model into a form suitable for use in the GoldSim models are discussed in Section 3. Section 4 presents the results of the model development effort and discusses some of the uncertainties involved. Eight attachments that provide details about the components and data used in this groundwater pathway model are also included with this report. The groundwater modeling effort reported here is a revision of the work that was conducted in 2005 (Stauffer et al., 2005a) in support of the 2008 Area G performance assessment and composite analysis (LANL, 2008). The revision effort was undertaken primarily to incorporate new geologic information that has been collected since 2003 at, and in the vicinity of, Area G. The new data were used to create a more accurate geologic framework model (GFM) that forms the basis of the numerical modeling of the site’s long-term performance. The groundwater modeling uses mean hydrologic properties of the geologic strata underlying Area G; this revision includes an evaluation of the impacts that natural variability in these properties may have on the model projections.

  8. Interpreting DNAPL saturations in a laboratory-scale injection using one- and two-dimensional modeling of GPR Data

    Science.gov (United States)

    Johnson, R.H.; Poeter, E.P.

    2005-01-01

    Ground-penetrating radar (GPR) is used to track a dense non-aqueous phase liquid (DNAPL) injection in a laboratory sand tank. Before modeling, the GPR data provide a qualitative image of DNAPL saturation and movement. One-dimensional (1D) GPR modeling provides a quantitative interpretation of DNAPL volume within a given thickness during and after the injection. DNAPL saturation in sublayers of a specified thickness could not be quantified because calibration of the 1D GPR model is nonunique when both permittivity and depth of multiple layers are unknown. One-dimensional GPR modeling of the sand tank indicates geometric interferences in a small portion of the tank. These influences are removed from the interpretation using an alternate matching target. Two-dimensional (2D) GPR modeling provides a qualitative interpretation of the DNAPL distribution through pattern matching and tests for possible 2D influences that are not accounted for in the 1D GPR modeling. Accurate quantitative interpretation of DNAPL volumes using GPR modeling requires (1) identification of a suitable target that produces a strong reflection and is not subject to any geometric interference; (2) knowledge of the exact depth of that target; and (3) use of two-way radar-wave travel times through the medium to the target to determine the permittivity of the intervening material, which eliminates reliance on signal amplitude. With geologic conditions that are suitable for GPR surveys (i.e., shallow depths, low electrical conductivities, and a known reflective target), the procedures in this laboratory study can be adapted to a field site to delineate shallow DNAPL source zones.

  9. An optimal generic model for multi-parameters and big data optimizing: a laboratory experimental study

    Science.gov (United States)

    Utama, D. N.; Ani, N.; Iqbal, M. M.

    2018-03-01

    Optimization is a process for finding parameter (parameters) that is (are) able to deliver an optimal value for an objective function. Seeking an optimal generic model for optimizing is a computer science study that has been being practically conducted by numerous researchers. Generic model is a model that can be technically operated to solve any varieties of optimization problem. By using an object-oriented method, the generic model for optimizing was constructed. Moreover, two types of optimization method, simulated-annealing and hill-climbing, were functioned in constructing the model and compared to find the most optimal one then. The result said that both methods gave the same result for a value of objective function and the hill-climbing based model consumed the shortest running time.

  10. Urban Multisensory Laboratory, AN Approach to Model Urban Space Human Perception

    Science.gov (United States)

    González, T.; Sol, D.; Saenz, J.; Clavijo, D.; García, H.

    2017-09-01

    An urban sensory lab (USL or LUS an acronym in Spanish) is a new and avant-garde approach for studying and analyzing a city. The construction of this approach allows the development of new methodologies to identify the emotional response of public space users. The laboratory combines qualitative analysis proposed by urbanists and quantitative measures managed by data analysis applications. USL is a new approach to go beyond the borders of urban knowledge. The design thinking strategy allows us to implement methods to understand the results provided by our technique. In this first approach, the interpretation is made by hand. However, our goal is to combine design thinking and machine learning in order to analyze the qualitative and quantitative data automatically. Now, the results are being used by students from the Urbanism and Architecture courses in order to get a better understanding of public spaces in Puebla, Mexico and its interaction with people.

  11. Model-based beam control for illumination of remote objects, part II: laboratory testbed

    Science.gov (United States)

    Basu, Santasri; Voelz, David; Chandler, Susan M.; Lukesh, Gordon W.; Sjogren, Jon

    2004-10-01

    When a laser beam propagates through the atmosphere, it is subject to corrupting influences including mechanical vibrations, turbulence and tracker limitations. As a result, pointing errors can occur, causing loss of energy or signal at the target. Nukove Scientific Consulting has developed algorithms to estimate these pointing errors from the statistics of the return photons from the target. To prove the feasibility of this approach for real-time estimation, an analysis tool called RHINO was developed by Nukove. Associated with this effort, New Mexico State University developed a laboratory testbed, the ultimate objective being to test the estimation algorithms under controlled conditions and to stream data into RHINO to prove the feasibility of real-time operation. The present paper outlines the description of this testbed and the results obtained through RHINO when the testbed was used to test the estimation approach.

  12. Boiling water reactor containment modeling and analysis at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Holcomb, E.E. III; Wilson, G.E.

    1984-01-01

    Under the auspices of the United States Nuclear Regulatory Commission, severe accidents are being studied at the Idaho National Engineering Laboratory. The boiling water reactor (BWR) studies have focused on postulated anticipated transients without scram (ATWS) accidents which might contribute to severe core damage or containment failure. A summary of the containment studies is presented in the context of the analytical tools (codes) used, typical transient simulation results and the need for prototypical containment data. All of these are related to current and future analytical capabilities. It is shown that torus temperatures during the ATWS depart from limiting conditions for BWR T-quencher operation, outside of which stable steam condensation has not been proven

  13. Validation of numerical model of a liquid flow in a tundish by laboratory measurements

    Directory of Open Access Journals (Sweden)

    T. Merder

    2014-07-01

    Full Text Available The article presents results of physical and numerical modelling of steel flow through a tundish of continuous casting machine. In numerical calculations the influence of mesh density was tested and the correctness of the flow description in the near-wall region was checked using Standard Wall Function model. Obtained results were verified using experimental results of velocity field (PIV method coming from a water tundish model.

  14. Electric Conduction in Solids: a Pedagogical Approach Supported by Laboratory Measurements and Computer Modelling Environments

    Science.gov (United States)

    Bonura, A.; Capizzo, M. C.; Fazio, C.; Guastella, I.

    2008-05-01

    In this paper we present a pedagogic approach aimed at modeling electric conduction in semiconductors, built by using NetLogo, a programmable modeling environment for building and exploring multi-agent systems. `Virtual experiments' are implemented to confront predictions of different microscopic models with real measurements of electric properties of matter, such as resistivity. The relations between these electric properties and other physical variables, like temperature, are, then, analyzed.

  15. Observations and Modeling of Long Negative Laboratory Discharges: Identifying the Physics Important to an Electrical Spark in Air

    Energy Technology Data Exchange (ETDEWEB)

    Biagi, C J; Uman, M A

    2011-12-13

    There are relatively few reports in the literature focusing on negative laboratory leaders. Most of the reports focus exclusively on the simpler positive laboratory leader that is more commonly encountered in high voltage engineering [Gorin et al., 1976; Les Renardieres Group, 1977; Gallimberti, 1979; Domens et al., 1994; Bazelyan and Raizer 1998]. The physics of the long, negative leader and its positive counterpart are similar; the two differ primarily in their extension mechanisms [Bazelyan and Raizer, 1998]. Long negative sparks extend primarily by an intermittent process termed a 'step' that requires the development of secondary leader channels separated in space from the primary leader channel. Long positive sparks typically extend continuously, although, under proper conditions, their extension can be temporarily halted and begun again, and this is sometimes viewed as a stepping process. However, it is emphasized that the nature of positive leader stepping is not like that of negative leader stepping. There are several key observational studies of the propagation of long, negative-polarity laboratory sparks in air that have aided in the understanding of the stepping mechanisms exhibited by such sparks [e.g., Gorin et al., 1976; Les Renardieres Group, 1981; Ortega et al., 1994; Reess et al., 1995; Bazelyan and Raizer, 1998; Gallimberti et al., 2002]. These reports are reviewed below in Section 2, with emphasis placed on the stepping mechanism (the space stem, pilot, and space leader). Then, in Section 3, reports pertaining to modeling of long negative leaders are summarized.

  16. Laboratory Testing, Characterization and Mathematical Modeling of the Moniwrist III by Ross-Hime Designs, Incorporated

    National Research Council Canada - National Science Library

    Skormin, Victor A

    2005-01-01

    .... It is proposed to enhance the system performance through development of an optimal comptroller extending the conventional state-variable and model reference control laws, with dynamic programming...

  17. An Evaluation of the Instruction Carried out with Printed Laboratory Materials Designed in Accordance with 5E Model: Reflection of Light and Image on a Plane Mirror

    Science.gov (United States)

    Ayvaci, Hakan Sevki; Yildiz, Mehmet; Bakirci, Hasan

    2015-01-01

    This study employed a print laboratory material based on 5E model of constructivist learning approach to teach reflection of light and Image on a Plane Mirror. The effect of the instruction which conducted with the designed print laboratory material on academic achievements of prospective science and technology teachers and their attitudes towards…

  18. On the Modelling and Control of a Laboratory Prototype of a Hydraulic Canal Based on a TITO Fractional-Order Model

    Directory of Open Access Journals (Sweden)

    Andres San-Millan

    2017-08-01

    Full Text Available In this paper a two-input, two-output (TITO fractional order mathematical model of a laboratory prototype of a hydraulic canal is proposed. This canal is made up of two pools that have a strong interaction between them. The inputs of the TITO model are the pump flow and the opening of an intermediate gate, and the two outputs are the water levels in the two pools. Based on the experiments developed in a laboratory prototype the parameters of the mathematical models have been identified. Then, considering the TITO model, a first control loop of the pump is closed to reproduce real-world conditions in which the water level of the first pool is not dependent on the opening of the upstream gate, thus leading to an equivalent single input, single output (SISO system. The comparison of the resulting system with the classical first order systems typically utilized to model hydraulic canals shows that the proposed model has significantly lower error: about 50%, and, therefore, higher accuracy in capturing the canal dynamics. This model has also been utilized to optimize the design of the controller of the pump of the canal, thus achieving a faster response to step commands and thus minimizing the interaction between the two pools of the experimental platform.

  19. Modeling Photovoltaic Module-Level Power Electronics in the System Advisor Model; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-07-01

    Module-level power electronics, such as DC power optimizers, microinverters, and those found in AC modules, are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software. This paper extends the work completed at NREL that provided recommendations to model the performance of distributed power electronics in NREL’s popular PVWatts calculator [1], to provide similar guidelines for modeling these technologies in NREL's more complex System Advisor Model (SAM). Module-level power electronics - such as DC power optimizers, microinverters, and those found in AC modules-- are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software.

  20. The Red Sea: A Natural Laboratory for Wind and Wave Modeling

    KAUST Repository

    Langodan, Sabique

    2014-12-01

    The Red Sea is a narrow, elongated basin that is more than 2000km long. This deceivingly simple structure offers very interesting challenges for wind and wave modeling, not easily, if ever, found elsewhere. Using standard meteorological products and local wind and wave models, this study explores how well the general and unusual wind and wave patterns of the Red Sea could be reproduced. The authors obtain the best results using two rather opposite approaches: the high-resolution Weather Research Forecasting (WRF) local model and the slightly enhanced surface winds from the global European Centre for Medium-Range Weather Forecasts model. The reasons why these two approaches produce the best results and the implications on wave modeling in the Red Sea are discussed. The unusual wind and wave patterns in the Red Sea suggest that the currently available wave model source functions may not properly represent the evolution of local fields. However, within limits, the WAVEWATCH III wave model, based on Janssen\\'s and also Ardhuin\\'s wave model physics, provides very reasonable results in many cases. The authors also discuss these findings and outline related future work.

  1. Gray's Reinforcement Sensitivity Model and Child Psychopathology: Laboratory and Questionnaire Assessment of the BAS and BIS

    Science.gov (United States)

    Colder, Craig R.; O'Connor, Roisin M.

    2004-01-01

    The Behavioral Approach System (BAS) and Behavioral Inhibition System (BIS) are widely studied components of Gray's sensitivity to reinforcement model. There is growing interest in integrating the BAS and BIS into models of risk for psychopathology, however, few measures assess BAS and BIS functioning in children. We adapted a questionnaire…

  2. Development of a comprehensive source term model for the Subsurface Disposal Area at the Idaho National Engineering and Environmental Laboratory

    International Nuclear Information System (INIS)

    1997-01-01

    The first detailed comprehensive simulation study to evaluate fate and transport of wastes disposed in the Subsurface Disposal Area (SDA), at the Radioactive Waste Management Complex (RWMC), Idaho National Engineering and Environmental Laboratory (INEEL) has recently been conducted. One of the most crucial parts of this modeling was the source term or release model. The current study used information collected over the last five years defining contaminant specific information including: the amount disposed, the waste form (physical and chemical properties) and the type of container used for each contaminant disposed. This information was used to simulate the release of contaminants disposed in the shallow subsurface at the SDA. The DUST-MS model was used to simulate the release. Modifications were made to allow the yearly disposal information to be incorporated. The modeling includes unique container and release rate information for each of the 42 years of disposal. The results from this simulation effort are used for both a groundwater and a biotic uptake evaluation. As part of this modeling exercise, inadequacies in the available data relating to the release of contaminants have been identified. The results from this modeling study have been used to guide additional data collection activities at the SDA for purposes of increasing confidence in the appropriateness of model predictions

  3. Photometrics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose:The Photometrics Laboratory provides the capability to measure, analyze and characterize radiometric and photometric properties of light sources and filters,...

  4. Blackroom Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Enables evaluation and characterization of materials ranging from the ultraviolet to the longwave infrared (LWIR).DESCRIPTION: The Blackroom Laboratory is...

  5. Target Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — [Part of the ATLAS user facility.] The Physics Division operates a target development laboratory that produces targets and foils of various thickness and substrates,...

  6. Large-Eddy / Reynolds-Averaged Navier-Stokes Simulations of a Dual-Mode Scramjet Combustor

    Science.gov (United States)

    Fulton, Jesse A.; Edwards, Jack R.; Hassan, Hassan A.; Rockwell, Robert; Goyne, Christopher; McDaniel, James; Smith, Chad; Cutler, Andrew; Johansen, Craig; Danehy, Paul M.; hide

    2012-01-01

    Numerical simulations of reacting and non-reacting flows within a scramjet combustor configuration experimentally mapped at the University of Virginia s Scramjet Combustion Facility (operating with Configuration A ) are described in this paper. Reynolds-Averaged Navier-Stokes (RANS) and hybrid Large Eddy Simulation / Reynolds-Averaged Navier-Stokes (LES / RANS) methods are utilized, with the intent of comparing essentially blind predictions with results from non-intrusive flow-field measurement methods including coherent anti-Stokes Raman spectroscopy (CARS), hydroxyl radical planar laser-induced fluorescence (OH-PLIF), stereoscopic particle image velocimetry (SPIV), wavelength modulation spectroscopy (WMS), and focusing Schlieren. NC State's REACTMB solver was used both for RANS and LES / RANS, along with a 9-species, 19- reaction H2-air kinetics mechanism by Jachimowski. Inviscid fluxes were evaluated using Edwards LDFSS flux-splitting scheme, and the Menter BSL turbulence model was utilized in both full-domain RANS simulations and as the unsteady RANS portion of the LES / RANS closure. Simulations were executed and compared with experiment at two equivalence ratios, PHI = 0.17 and PHI = 0.34. Results show that the PHI = 0.17 flame is hotter near the injector while the PHI = 0.34 flame is displaced further downstream in the combustor, though it is still anchored to the injector. Reactant mixing was predicted to be much better at the lower equivalence ratio. The LES / RANS model appears to predict lower overall heat release compared to RANS (at least for PHI = 0.17), and its capability to capture the direct effects of larger turbulent eddies leads to much better predictions of reactant mixing and combustion in the flame stabilization region downstream of the fuel injector. Numerical results from the LES/RANS model also show very good agreement with OH-PLIF and SPIV measurements. An un-damped long-wave oscillation of the pre-combustion shock train, which caused

  7. A coupled THMC model of a heating and hydration laboratory experiment in unsaturated compacted FEBEX bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, L.; Samper, J.; Montenegro, L.; Fernandez, A.M.

    2010-05-01

    Unsaturated compacted bentonite is foreseen by several countries as a backfill and sealing material in high-level radioactive waste repositories. The strong interplays between thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration stage of a repository call for fully coupled THMC models. Validation of such THMC models is prevented by the lack of comprehensive THMC experiments and the difficulties of experimental methods to measure accurately the chemical composition of bentonite porewater. We present here a non-isothermal multiphase flow and multicomponent reactive solute transport model for a deformable medium of a heating and hydration experiment performed on a sample of compacted FEBEX bentonite. Besides standard solute transport and geochemical processes, the model accounts for solute cross diffusion and thermal and chemical osmosis. Bentonite swelling is solved with a state-surface approach. The THM model is calibrated with transient temperature, water content and porosity data measured at the end of the experiment. The reactive transport model is calibrated with porewater chemical data derived from aqueous extract data. Model results confirm that thermal osmosis is relevant for the hydration of FEBEX bentonite while chemical osmosis can be safely neglected. Dilution and evaporation are the main processes controlling the concentration of conservative species. Dissolved cations are mostly affected by calcite dissolution-precipitation and cation exchange reactions. Dissolved sulphate is controlled by gypsum/anhydrite dissolution-precipitation. pH is mostly buffered by protonation/deprotonation via surface complexation. Computed concentrations agree well with inferred aqueous extract data at all sections except near the hydration boundary where cation data are affected by a sampling artifact. The fit of Cl{sup -} data is excellent except for the data near the heater. The largest deviations of the model from inferred aqueous

  8. Behavioral Neuroscience Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — This lab supports cognitive research using rodent models. Capabilities for behavioral assessments include:Morris water maze and Barnes maze (spatial memory)elevate...

  9. Laboratory investigations

    International Nuclear Information System (INIS)

    Handin, J.

    1980-01-01

    Our task is to design mined-repository systems that will adequately secure high-level nuclear waste for at least 10,000 yr and that will be mechanically stable for 50 to 100-yr periods of retrievability during which mistakes could be corrected and a valuable source of energy could be reclaimed, should national policy on the reprocessing of spent fuel ever change. The only credible path for the escape of radionuclides from the repository to the biosphere is through ground-water, and in hard rock, bulk permeability is largely governed by natural and artificial fracture systems. Catastrophic failure of an excavation in hard rock is likely to occur at the weakest links - the discontinuities in the rock mass that is perturbed first by mining and then by radiogenic heating. The laboratory can contribute precise measurements of the pertinent thermomechanical, hydrological and chemical properties and improve our understanding of the fundamental processes through careful experiments under well controlled conditions that simulate the prototype environment. Thus laboratory investigations are necessary, but they are not sufficient, for conventional sample sizes are small relative to natural defects like joints - i.e., the rock mass is not a continuum - and test durations are short compared to those that predictive modeling must take into account. Laboratory investigators can contribute substantially more useful data if they are provided facilities for testing large specimens(say one cubic meter) and for creep testing of all candidate host rocks. Even so, extrapolations of laboratory data to the field in neither space nor time are valid without the firm theoretical foundations yet to be built. Meanwhile in-situ measurements of structure-sensitive physical properties and access to direct observations of rock-mass character will be absolutely necessary

  10. Complete Evaluation of Available Laboratory-scale Data for the Independence Model

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Troy Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kress, Joel David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bhat, Kabekode Ghanasham [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-30

    Year 1 Objectives (August 2016 – December 2016) – The original Independence model is a sequentially regressed set of parameters from numerous data sets in the Aspen Plus modeling framework. The immediate goal with the basic data model is to collect and evaluate those data sets relevant to the thermodynamic submodels (pure substance heat capacity, solvent mixture heat capacity, loaded solvent heat capacities, and volatility data). These data are informative for the thermodynamic parameters involved in both vapor-liquid equilibrium, and in the chemical equilibrium of the liquid phase.

  11. Ultra low injection angle fuel holes in a combustor fuel nozzle

    Science.gov (United States)

    York, William David

    2012-10-23

    A fuel nozzle for a combustor includes a mixing passage through which fluid is directed toward a combustion area and a plurality of swirler vanes disposed in the mixing passage. Each swirler vane of the plurality of swirler vanes includes at least one fuel hole through which fuel enters the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes thereby decreasing a flameholding tendency of the fuel nozzle. A method of operating a fuel nozzle for a combustor includes flowing a fluid through a mixing passage past a plurality of swirler vanes and injecting a fuel into the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes.

  12. NOx results from two combustors tested on medium BTU coal gas

    Science.gov (United States)

    Sherlock, T. P.; Carl, D. E.; Vermes, G.; Schwab, J.; Notardonato, J. J.

    1982-01-01

    The results of tests of two combustor configurations using coal gas from a 25 ton/day fluidized bed coal gasifier are reported. The trials were run with a ceramic-lined, staged rich/lean burner and an integral, all metal multiannular swirl burner (MASB) using a range of temperatures and pressures representative of industrial turbine inlet conditions. A lean mixture was examined at 104, 197, and 254 Btu/Scf, yielding NO(x) emissions of 5, 20, and 70 ppmv, respectively. The MASB was employed only with a gas rated at 220-270 Btu/Scf, producing 80 ppmv NO(x) at rated engine conditions. The results are concluded to be transferrable to current machines. Further tests on the effects of gas composition, the scaling of combustors to utility size, and the development of improved wall cooling techniques and variable geometry are indicated.

  13. Numerical analysis of lean premixed combustor fueled by propane-hydrogen mixture

    Directory of Open Access Journals (Sweden)

    Mahjoub Mustafa Makhzoum Ali

    2017-01-01

    Full Text Available A numerical investigation of combustion of propane-hydrogen mixture in a swirl premixed micro gas turbine combustor is presented. The effects of hydrogen addition into propane on temperature distribution in the combustor, reaction rates of propane and hydrogen and NOx emissions for different equivalence ratios and swirl numbers are given. The propane-hydrogen mixture of 90/10% by volume was assumed. The numerical results and measurements of NOx emissions for pure propane are compared. Excellent agreements are found for all equivalence ratios and swirl numbers, except for the highest swirl number (1.13. It is found that the addition of hydrogen into propane increases NOx emission. On the other hand, the increase of swirl number and the decrease of equivalence ratio decrease the NOx emissions.

  14. North Pacific Acoustic Laboratory: Analysis of Shadow Zone Arrivals and Acoustic Propagation in Numerical Ocean Models

    National Research Council Canada - National Science Library

    Dushaw, Brian

    2009-01-01

    ... depth of the receiver lies well below the depths of the predicted cusps. Several models for the temperature and salinity in the North Pacific Ocean were obtained and processed to enable simulations of acoustic propagation for comparison to the observations...

  15. Searching for beyond the minimal supersymmetric standard model at the laboratory and in the sky

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Min

    2010-09-15

    We study the collider signals as well as Dark Matter candidates in supersymmetric models. We show that the collider signatures from a supersymmetric Grand Unification model based on the SO(10) gauge group can be distinguishable from those from the (constrained) minimal supersymmetric Standard Model, even though they share some common features. The N=2 supersymmetry has the characteristically distinct phenomenology, due to the Dirac nature of gauginos, as well as the extra adjoint scalars. We compute the cold Dark Matter relic density including a class of one-loop corrections. Finally, we discuss the detectability of neutralino Dark Matter candidate of the SO(10) model by the direct and indirect Dark Matter search experiments. (orig.)

  16. BioVeL: a virtual laboratory for data analysis and modelling in biodiversity science and ecology.

    Science.gov (United States)

    Hardisty, Alex R; Bacall, Finn; Beard, Niall; Balcázar-Vargas, Maria-Paula; Balech, Bachir; Barcza, Zoltán; Bourlat, Sarah J; De Giovanni, Renato; de Jong, Yde; De Leo, Francesca; Dobor, Laura; Donvito, Giacinto; Fellows, Donal; Guerra, Antonio Fernandez; Ferreira, Nuno; Fetyukova, Yuliya; Fosso, Bruno; Giddy, Jonathan; Goble, Carole; Güntsch, Anton; Haines, Robert; Ernst, Vera Hernández; Hettling, Hannes; Hidy, Dóra; Horváth, Ferenc; Ittzés, Dóra; Ittzés, Péter; Jones, Andrew; Kottmann, Renzo; Kulawik, Robert; Leidenberger, Sonja; Lyytikäinen-Saarenmaa, Päivi; Mathew, Cherian; Morrison, Norman; Nenadic, Aleksandra; de la Hidalga, Abraham Nieva; Obst, Matthias; Oostermeijer, Gerard; Paymal, Elisabeth; Pesole, Graziano; Pinto, Salvatore; Poigné, Axel; Fernandez, Francisco Quevedo; Santamaria, Monica; Saarenmaa, Hannu; Sipos, Gergely; Sylla, Karl-Heinz; Tähtinen, Marko; Vicario, Saverio; Vos, Rutger Aldo; Williams, Alan R; Yilmaz, Pelin

    2016-10-20

    Making forecasts about biodiversity and giving support to policy relies increasingly on large collections of data held electronically, and on substantial computational capability and capacity to analyse, model, simulate and predict using such data. However, the physically distributed nature of data resources and of expertise in advanced analytical tools creates many challenges for the modern scientist. Across the wider biological sciences, presenting such capabilities on the Internet (as "Web services") and using scientific workflow systems to compose them for particular tasks is a practical way to carry out robust "in silico" science. However, use of this approach in biodiversity science and ecology has thus far been quite limited. BioVeL is a virtual laboratory for data analysis and modelling in biodiversity science and ecology, freely accessible via the Internet. BioVeL includes functions for accessing and analysing data through curated Web services; for performing complex in silico analysis through exposure of R programs, workflows, and batch processing functions; for on-line collaboration through sharing of workflows and workflow runs; for experiment documentation through reproducibility and repeatability; and for computational support via seamless connections to supporting computing infrastructures. We developed and improved more than 60 Web services with significant potential in many different kinds of data analysis and modelling tasks. We composed reusable workflows using these Web services, also incorporating R programs. Deploying these tools into an easy-to-use and accessible 'virtual laboratory', free via the Internet, we applied the workflows in several diverse case studies. We opened the virtual laboratory for public use and through a programme of external engagement we actively encouraged scientists and third party application and tool developers to try out the services and contribute to the activity. Our work shows we can deliver an operational

  17. Modeling HF Gain Generator F-Atom Flows

    National Research Council Canada - National Science Library

    Kwok, Munson

    2003-01-01

    Control volume analysis and one-dimensional reacting gasdynamics have been combined with a unique thermal-mechanical model of a combustor vessel to estimate production of fluorine atoms at the nozzle exit plane...

  18. Improved Kinetic Models for High-Speed Combustion Simulation

    National Research Council Canada - National Science Library

    Montgomery, C. J; Tang, Q; Sarofim, A. F; Bockelie, M. J; Gritton, J. K; Bozzelli, J. W; Gouldin, F. C; Fisher, E. M; Chakravarthy, S

    2008-01-01

    Report developed under an STTR contract. The overall goal of this STTR project has been to improve the realism of chemical kinetics in computational fluid dynamics modeling of hydrocarbon-fueled scramjet combustors...

  19. Comparative statistical analysis of strong zonal jet flows generated in a laboratory device and a Global Climate Model.

    Science.gov (United States)

    Cabanes, S.; Spiga, A.; Guerlet, S.; Aurnou, J. M.; Favier, B.; Le Bars, M.

    2017-12-01

    The strong zonal (i.e. east-west) jet flows on the gas giants, Jupiter and Saturn, have persisted for hundreds of years. Zonal jets are large-scale features ubiquitous in planetary atmosphere and result from multi-scales interactions in rapidly rotating turbulent flows. Here we use a new Saturn Global Climate Model (GCM) coupling seasonal radiative model tailored for Saturn with a new hydrodynamical solver, developed in Laboratoire de Météorology Dynamique, which uses an original icosahedral mapping of the planetary sphere to ensure excellent conservation and scalability properties in massively parallel computing resources. Strong and quasi-steady Saturn jets are reproduced in our GCM simulations with both unprecedented horizontal resolutions (reference at 1/2 ° latitude/longitude, and tests at 1/4 ° and 1/8 ° ), integrated time (up to ten simulated Saturn years), and large vertical extent (from the troposphere to the stratosphere). We perform statistical analysis on the resulting flows to explore scales interactions and kinetic energy distribution at all scale. It appears that horizontal resolution as well as subgrid-scale (unresolved) dissipation, included as an additional hyperdiffusion term, strongly affect jets' intensity and statistical properties. In parallel, we set the first laboratory device capable to achieve the relevant regime to form planetary like zonal jets. We report that in a rapidly rotating cylindrical container, turbulent laboratory flow naturally generate multiple, alternating jets that share basic properties of the one observed on gas planets. By performing similar statistical analysis we directly confront flow properties of laboratory versus GCM generated jets and point out the effect of limited numerical resolution and subgrid-scale assumptions on atmospheric dynamics at large/jets scale.

  20. Gender Comparison of Medical Student Microsurgical Skills in a Laboratory Model.

    Science.gov (United States)

    Sudario-Lumague, Rowena; Chiang, Yuan-Cheng; Lin, Tsan-Shiun

    2018-02-16

     Perceived gender-related differences in surgical skills could limit opportunities available for any aspiring surgeon. There should be more available literature and logical analysis of these observations. The objective of this study is to evaluate the microsurgical skills of male and female medical students using a standard scale in the laboratory.  This study included medical students enrolled in the Kaohsiung Chang Gung Memorial Hospital from 2002 to 2015 who were evaluated by a senior consultant for their microsurgical skills. A standard numeric scale was used to evaluate their suturing technique after basic microsurgical training. Differences in the scores between male and female medical students were evaluated using statistical analysis.  A total of 578 medical students were included in the study. There were 393 males (68%) and 185 females (32%). Using statistical analysis, there is no significant difference in the distribution of scores ( P value = 0.78) and mean scores ( P value = 0.75) between the two groups.  This study shows that microsurgical skills of male and female medical students are similar. Equal opportunities in the eventual pursuit of the surgical specialties should be available regardless of gender. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.