bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation of Flow Losses in Rotating Passages of Gas Turbine Cooling Systems
Authors: Brillert D. , Reichert A. W. , Simon H. 
Published: December 2014

The continuous improvement in thermal efficiency of gas turbines is primarily achieved by increasing the turbine inlet temperatures without, however, affecting the thermal stability and the fatigue strength of the blades which must be guaranteed for their entire service life. The precise analysis of secondary air systems is therefore of crucial importance for the design of gas turbines.
Stationary and rotating passages constitute important elements of secondary air systems, and this paper focuses on the calculation of the characteristics of fluid flow through stationary and rotating passages (or bores) as a function of passage length, asymmetric inflow (i.e. crossflow at the inlet) and inlet edge geometry (i.e. rounded or sharp–edged inlets). A simple physical model is developed on the basis of the simple and thoroughly investigated passage flow. The model is then matched to a large number of test results taken from the literature. The result is a versatile tool for calculating flow losses in rotating and stationary passages.
Computations of Film Cooling From Holes With Struts
Authors: Shih T. I-P. , Lin Y.-L. , Chyu M. K. , Gogineni S. 
Published: December 2014

Computations were performed to study the three-dimensional flow and heat transfer on a flat plate cooled by jets, injected from a plenum through one row of film-cooling holes in which each hole is fitted with a strut in the form of a circular cylinder. Three different configurations of the film-cooling hole were investigated: without strut, with streamwise strut, and with spanwise strut. For all configurations, the film-cooling holes are inclined at 35°, and the coolant-to-mainflow density and mass-flux ratios are 1.6 and 0.5, respectively. The focus of this study is to understand how struts in holes affect film cooling jets and their interactions with the mainflow in forming a protective layer of cooler fluid over the plate.
This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy. Effects of turbulence was modeled by a low Reynolds number k-ω closure known as the shear-stress-transport (SST) model. Solutions were generated by a cell-centered finite-volume method that uses third-order accurate flux-difference splitting of Roe with limiters, multigrid acceleration of a diagonalized ADI scheme with local time stepping, and patched/overlapped structured grids. In the computations, the flow is resolved not just in the cooling-jet/mainflow interaction region, but also inside the film-cooling holes and in the plenum. Computed results for adiabatic effectiveness for the case without struts were compared with experimental data, and reasonably good agreements were obtained.
Thermoeconomic Analysis of Gas Turbine Based Cycles
Authors: Massardo A. F. , Scialò M. 
Published: December 2014

The thermoeconomic analysis of gas turbine based cycles is presented and discussed in this paper. The thermoeconomic analysis has been performed using the ThermoEconomic Modular Program (TEMP V.5.0) developed by the Authors (Agazzani and Massardo, 1997). The modular structure of the code allows the thermoeconomic analysis for different scenarios (turbine inlet temperature, pressure ratio, fuel cost, installation costs, operating hours per year, etc.) of a large number of advanced gas turbine cycles to be obtained in a fast and reliable way. The simple cycle configuration results have been used to assess the cost functions and coefficient values.
The results obtained for advanced gas turbine based cycles (intercooled, re-heated, regenerated and their combinations) are presented using new and useful representations: cost vs. efficiency, cost vs. specific work, and cost vs. pressure ratio. The results, including productive diagram configurations, are discussed in detail and compared to one another.
Design and Initial Development of Monolithic Cross-Flow Ceramic Hot-Gas Filters
Authors: Vaubert Virginie , Stinton David P. , Barra Chris , Limaye Santosh 
Published: December 2014

Advanced, coal-fueled, power generation systems utilizing pressurized fluidized bed combustion (PFBC) and integrated gasification combined cycle (IGCC) technologies are currently being developed for high-efficiency, low emissions, and low-cost power generation. In spite of the advantages of these promising technologies, the severe operating environment often leads to material degradation and loss of performance in the barrier filters used for particle entrapment. To address this problem, LoTEC Inc., and Oak Ridge National Laboratory are jointly designing and developing a monolithic cross-flow ceramic hot-gas filter. The filter concept involves a truly monolithic cross-flow design that is resistant to delamination, can be easily fabricated, and offers flexibility of geometry and material make-up.
During Phase I of the program, a thermo-mechanical analysis was performed to determine how a cross-flow filter would respond both thermally and mechanically to a series of thermal and mechanical loads. The cross-flow filter mold was designed accordingly, and the materials selection was narrowed down to Ca0.5Sr0.5Zr4P6O24 (CS-50) and 2Al2O3−3SiO2 (mullite). A fabrication process was developed using gelcasting technology and monolithic cross-flow filters were fabricated. The program focuses on obtaining optimum filter permeability and testing the corrosion resistance of the candidate materials.
A Comparative View of Engineering Training in the US, Germany, and France With Special Focus on Turbomachinery-Relevant Skills
Authors: von Hoyningen-Huene Martin , Wedig Walter , Jeanpert Julie , Edel André 
Published: December 2014

In this study, the status quo of university engineering education in the US, Germany, and France is presented. The different ways of training mechanical and aeronautical engineers are compared. Based on this, the strengths and weaknesses of their “products”, the outcoming engineers at Bachelor’s and Master’s level, are analyzed in respect to the needs in industry.
After a presentation of new tendencies and concepts in engineering education in the three countries under concern, the authors outline their vision of an engineer’s training. Some of these proposals are currently under realization in the Department of Mechanical Engineering of the University of Karlsruhe and at the Grande Ecole ENSAM in Paris that jointly have pursued this broad study.
An Interactive Method for Teaching Turbine Design
Authors: Ramsden K. W. 
Published: December 2014

The implementation of new technology in the gas turbine industry is accelerating at a rate which demands increasing specialisation by its engineering design staff. Simultaneously, this industry has been adopting concurrent engineering practices to reduce product lead-time. Accordingly, the industry now requires its engineers to acquire competence in a wide range of technological disciplines together with a thorough understanding of the demands of design optimisation for the whole engine.
Against this background, educational providers must respond to these increasing demands with teaching programmes that enable a more rapid and deeper understanding of a very complex product. The ambition of the teacher, however, to prepare the student will continue to be limited by time constraints within lecture courses. Hitherto, this has normally resulted in class worked examples which are necessarily narrow in scope and confined to a limited range of design cases.
To overcome these limitations, a portfolio of multimedia computer programs has been developed specifically for rapid and relevant learning purposes. Each is structured to facilitate in-depth understanding of the key interactions between aerodynamics, thermodynamics and mechanical integrity needed in gas turbine design and performance assessment.
This paper describes an interactive teaching method for turbine design optimisation using only the multimedia turbine design and performance module. Through the example of a case study, the preliminary design of a high pressure and low pressure turbine combination is undertaken initially by hand.
This first pass design leaves substantial scope for design optimisation through a series of workshops using only the software. Final design recommendations are subsequently based on comprehensive tutor led but fully interactive discussion. Particular emphasis is placed on the impact of design decisions on both the various technology issues and on the performance of other engine components.
Numerical and Experimental Study of Unsteady Flow Field and Vibration in Radial Inflow Turbines
Authors: Kreuz-Ihli T. , Filsinger D. , Schulz A. , Wittig S. 
Published: December 2014

The blades of turbocharger impellers are exposed to unsteady aerodynamic forces, which cause blade vibrations and may lead to failures. An indispensable requirement for a safe design of radial inflow turbines is a detailed knowledge of the exciting forces. Up to now, only few investigations relating to unsteady aerodynamic forces in radial turbines were presented. To give a detailed insight into the complex phenomena, a comprehensive research project was initiated at the Institut für Thermische Strömungsmaschinen, at the University of Karlsruhe.
A turbocharger test rig was installed in the high pressure, high temperature laboratory of the institute. The present paper gives a description of the test rig design and the measuring techniques. The flow field in a vaneless radial inflow turbine was analyzed using laser Doppler anemometry. First results of unsteady flow field investigations in the turbine scroll and unsteady phase resolved measurements of the flow field in the turbine rotor will be discussed. Moreover, results from finite element calculations analyzing frequencies and mode shapes are presented.
As vibrations in turbines of turbochargers are assumed to be predominantly excited by unsteady aerodynamic forces, a method to predict the actual transient flow in a radial turbine utilizing the commercial Navier Stokes solver TASCflow3d was developed. Results of the unsteady calculations are presented and comparisons with the measured unsteady flow field are made. As a major result, the excitation effect of the tongue region in a vaneless radial inflow turbine can be demonstrated.
300 KW Class, Semi-Closed Cycle Gas Turbine Engine Design Considerations
Authors: Rodgers C. 
Published: December 2014

The thermodynamic performances and relative sizing of small single shaft and two spool semi-closed cycle turbine engines (SCTE), for propulsion needs were studied relative to the conventional intercooled recuperative (ICR) open cycle gas turbine. The study indicated that the basic attributes of the SCTE are higher specific power, hp/pps inlet flow, a flat specific fuel consumption (SFC) characteristic, and potentially reduced exhaust emissions, at the expense of slightly higher SFC, lower power to weight ratio, and increased cost $/hp relative to the ICR.
The combustor is paramount to the successful operation of the SCTE in that the feedback (recirculated) flow, must be clean and devoid of particulates that could deposit on the heat transfer surfaces and turbo machinery. Additionally if high specific power is the primary design constraint high reticulation flow ratio combustor technology must be researched.
A conservative cycle analysis was conducted with current small gas turbine state-of-art component efficiencies and temperature limits for metallic hot-end components. The analysis was simplified by using existing gas properties for hydrocarbon air mixtures without oxygen depletion, or exhaust products in compression. Although the assumption that the intercooler and recuperator effectiveness and pressure drops remained constant provided a common datum, the part load performance analysis could benefit from the supplementation of improved heat exchanger algorithms.
Quantifying Fuel/Air Unmixedness in Premixing Nozzles Using an Acetone Fluorescence Technique
Authors: Stufflebeam John H. , Kendrick Donald W. , Sowa William A. , Snyder Timothy S. 
Published: December 2014

The ability of a lean-premixed combustion system to minimize emissions while maintaining combustion stability over the operating curve relies upon how well the fuel nozzle premixes the fuel and air. As the level of premixing increases, NOx emissions at a given flame temperature decrease until a perfectly premixed condition is achieved. The objective of this paper is to quantify the level of premixing achieved by a premixing nozzle using an acetone fluorescence technique and determine its relationship to NOx emissions and combustion stability.
The technique of using acetone fluorescence has been used as a fast and quantitative diagnostic to map the fuel-air distribution. This technique has been applied to the development of a lean premixing nozzle to measure the fuel air distribution at the fuel nozzle exit plane. In this study, the fuel air distribution is presented as 2-D images. The average fuel/air ratio and the standard deviation are calculated at various annular regions to determine the distribution as a function of radius. A single unmixedness parameter (σ/μ) over the entire annulus is also calculated to allow relative ranking of the various fuel nozzle configurations.
The fluorescence data is acquired for various nozzle hardware configurations in an atmospheric test facility. Fuel and air flow conditions are determined by scaling engine conditions to cold flow conditions and matching the fuel to air momentum ratio at the fuel injection site. Measured fuel/air distributions, 6 mm downstream of the nozzle exit plane, from the acetone fluorescence technique are correlated to emissions and acoustic measurements made at full pressure and temperature conditions in a single-nozzle test rig.
The paper includes a description of the acetone fluorescence technique, the method for optimizing the fuel/air distribution through changes to the main gas fuel injection array, and correlations made between the fuel/air distribution, nozzle geometry, power setting, emissions and combustor acoustics.
GT24/26 Advanced Cycle System Power Plant Progress for the New Millenium
Authors: Mayer Albrecht , van der Linden Septimus 
Published: December 2014

The GT24/26 Advance Cycle System ‘ACS’ was announced in 1993 as the first modern single shaft reheat combustion turbine to serve the power generation market. The ACS goal was to have higher efficiency and higher specific output than ‘F’ class machines already providing the first step to improved efficiency.
The innovative sequential combustion system (reheat) technology raised overall plant efficiencies to 58% LHV, a substantial improvement over the state of the art plant performance of 55% LHV at that time, without pushing the turbine inlet temperature envelope.
This paper will review progress of the power plant concepts that will serve the emerging Merchant Power market as a result of deregulation of the industry not only in the United States but in other countries as well. Operating experience as well as improvements will be reviewed of the current and future plants that will account for over 10 GW’s in the year 2000. Improvements to meet the challenges of the New Millenium continue through ABB R&D efforts as well as contributions to the DOE ATS program.
Deposition and Testing of Thermal Barrier Coatings on Gas Turbine Vanes
Authors: Tului M. , Gualco G. C. , Scarpellini R. 
Published: December 2014

An innovative methodology to deposit, by plasma spraying, ceramic thermal barrier coatings on gas turbine blades and vanes was developed. Such a methodology produces a pattern of microcracks in the coating, thus improving its thermal shock resistance.
After a laboratory campaign of process optimization and coating characterization, real components were coated with a 150 μm thick layer of NiCoCrAlY as a bond coat and a 300 μm thick layer of ZrO2, partially stabilised with 8%of Y2O3, as a top coat. In particular, four vanes, taken from the first stage of a land based gas turbine (V64.3, produced by Ansaldo), were coated on the whole airfoil.
The four vanes were submitted to a cyclic oxidation test in a burner rig simulating the operative conditions of a gas turbine. In particular, they were exposed to a gas flow with the same composition, temperature and speed of the inlet gas of a real gas turbine; moreover, they were cooled by an internal stream of compressed air for obtaining the same temperature profile of a vane in operation. The surface temperature of the vanes was monitored during the test by an optical pyrometer and the internal temperature by a thermocouple.
After 550 hours of test, corresponding to 550 cycles, the four vanes did not show any sign of damage.
The Hybrid Cycle: Integration of a Fuel Cell With a Gas Turbine
Authors: Leeper John D. 
Published: December 2014

The integration of a fuel cell and a gas turbine is a natural evolution in the quest for improved generation efficiency with clean emissions. Integration is achieved by using the gas turbine compressor as the air mover for the fuel cell, and using the high temperature exhaust of the fuel cell to supplant the gas turbine combustor.
Edison Technology Solutions (ETS), the California Energy Commission, the U. S. Department of Energy (DOE), and Siemens Westinghouse Power Corporation are jointly sponsoring a project to design and fabricate a hybrid cycle power system that couples a Pressurized Solid Oxide Fuel Cell (SOFC) generator module with a Micro Turbine Generator (MTG), to yield a system with a nominal capacity of 250 kW and a power generation efficiency approaching 60%. The SOFC will supply approximately 80% of the output power and the MTG 20%. The MTG functions primarily as a turbo charger for the SOFC with some additional shaft power available to turn an integral generator. The demonstration will be conducted at the University of California at Irvine. Startup is scheduled for the summer of 1999.
This project is expected to be the first demonstration of a hybrid cycle employing a pressurized SOFC to supplant the combustor of a gas turbine generator. The parameters of evaluation are the power output, electric generation efficiency, degradation characteristics, operability, and operating power range.
The primary project objective is to demonstrate successful startup and operation over the design power range at efficiencies approaching 60%. Secondary objectives are to evaluate operability, component reliability, and to conduct a design evaluation to develop improvements for subsequent designs.
One-Dimensional Performance Prediction of Subsonic Vaned Diffusers
Authors: Ribi Beat , Dalbert Peter 
Published: December 2014

A simple 1-d-theory to predict the performance of a diffuser using as few empirical factors as possible is presented. The prediction method uses two empirical functions to assess both the pressure recovery and the losses. The functions have been calibrated from experimental data from the company’s standard diffusers. The method is, however, adaptable for any type of subsonic vaned diffusers provided that the empirical functions can be calibrated from measurements.
The pressure rise in the diffuser is calculated from the continuity equation taking into account the blockage, while the losses are determined by means of displacement and momentum thickness. These values are calculated at design point from an integral boundary layer calculation. To take into account the influence of flow separation at off-design the calculated displacement and momentum thickness are increased according to empirical functions.
When designing a new impeller the method provides a simple way to evaluate the diffuser resulting in the best combination in terms of efficiency and range. It further provides a simple means of estimating the change to be expected in a known stage performance characteristic due to a modification of the diffuser geometry.
AbuO, a TolC-Like Outer Membrane Protein of Acinetobacter baumannii, Is Involved in Antimicrobial and Oxidative Stress Resistance
Authors: Srinivasan Vijaya Bharathi , Vaidyanathan Vasanth , Rajamohan Govindan 
Published: December 2014

ABSTRACT

Although
Acinetobacter baumannii
is well accepted as a nosocomial pathogen, only a few of the outer membrane proteins (OMPs) have been functionally characterized. In this study, we demonstrate the biological functions of AbuO, a homolog of TolC from
Escherichia coli
. Inactivation of
abuO
led to increased sensitivity to high osmolarity and oxidative stress challenge. The Δ
abuO
mutant displayed increased susceptibility to antibiotics, such as amikacin, carbenicillin, ceftriaxone, meropenem, streptomycin, and tigecycline, and hospital-based disinfectants, such as benzalkonium chloride and chlorhexidine. The reverse transcription (RT)-PCR analysis indicated increased expression of efflux pumps (resistance nodulation cell division [RND] efflux pump
acrD
, 8-fold; SMR-type
emrE
homolog, 12-fold; and major facilitator superfamily [MFS]-type
ampG
homolog, 2.7-fold) and two-component response regulators (
baeR
, 4.67-fold;
ompR
, 10.43-fold) in the Δ
abuO
mutant together with downregulation of
rstA
(4.22-fold) and the pilin chaperone (9-fold). The isogenic mutant displayed lower virulence in a nematode model (
P
< 0.01). Experimental evidence for the binding of MerR-type transcriptional regulator SoxR to radiolabeled
abuO
promoter suggests regulation of
abuO
by SoxR in
A. baumannii
.
Identification of a New Amide-Containing Thiazole as a Drug Candidate for Treatment of Chagas' Disease
Authors: Álvarez Guzmán , Varela Javier , Cruces Eugenia , Fernández Marcelo , Gabay Martín , Leal Sandra M. , Escobar Patricia , Sanabria Luis , Serna Elva , Torres Susana , Figueredo Thiel Susy J. , Yaluff Gloria , Vera de Bilbao Ninfa I. , Cerecetto Hugo , González Mercedes 
Published: December 2014

ABSTRACT

Although the parasitic infection Chagas' disease was described over 100 years ago, even now there are not suitable drugs. The available drugs nifurtimox and benznidazole have limited efficacies and tolerances, with proven mutagenic effects. Attempting to find appropriate drugs to deal with this problem, here we report on the development and pharmacological characterization of new amide-containing thiazoles. In the present study, we evaluated the
in vitro
and
in vivo
effects of new candidates against
Trypanosoma cruzi
, the etiological agent of Chagas' disease. The lead amide-containing thiazole derivative had potent
in vitro
activity, an absence of both
in vitro
mutagenic and
in vivo
clastogenic effects, and excellent
in vitro
selectivity and
in vivo
tolerance. The compound suppressed parasitemia in mice, modifying the anti-
T. cruzi
antibodies like the reference drug, benznidazole, and displayed the lowest mortality among the tested drugs. The present evidence suggests that this compound is a promising anti-
T. cruzi
agent surpassing the lead optimization stage in drug development and leading to a candidate for preclinical study.