scholarly journals Review of Recent Developments in Wave Rotor Combustion Technology

2009 ◽  
Vol 25 (4) ◽  
pp. 833-844 ◽  
Author(s):  
P. Akbari ◽  
M. R. Nalim
Keyword(s):  
Wave Rotor ◽  
Recent Developments ◽  
Combustion Technology

Combustion Technology for Low-Emissions Gas-Turbines: Some Recent Modeling Results

1996 ◽  
Vol 118 (3) ◽  
pp. 201-208 ◽  
Author(s):  
S. M. Correa ◽  
I. Z. Hu ◽  
A. K. Tolpadi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Spectroscopic Data ◽  
Physical Models ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Recent Developments ◽  
Combustion Technology ◽  
Computationally Intensive ◽  
Transport Method

Computer modeling of low-emissions gas-turbine combustors requires inclusion of finite-rate chemistry and its intractions with turbulence. The purpose of this review is to outline some recent developments in and applications of the physical models of combusting flows. The models reviewed included the sophisticated and computationally intensive velocity-composition pdf transport method, with applications shown for both a laboratory flame and for a practical gas-turbine combustor, as well as a new and computationally fast PSR-microstructure-based method, with applications shown for both premixed and nonpremixed flames. Calculations are compared with laserbased spectroscopic data where available. The review concentrates on natural-gas-fueled machines, and liquid-fueled machines operating at high power, such that spray vaporization effects can be neglected. Radiation and heat transfer is also outside the scope of this review.

Application of the Geared Turbofan With Constant Volume Combustor on Short-Range Aircraft: A Feasibility Study

2009 ◽  
Author(s):  
Fernando Colmenares Quintero ◽  
Rob Brink ◽  
Stephen Ogaji ◽  
Pericles Pilidis ◽  
Juan Carlos Colmenares Quintero ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Short Range ◽  
Operating Cost ◽  
Constant Volume ◽  
Superior Performance ◽  
Wave Rotor ◽  
Environmental Aspects ◽  
Direct Operating Cost ◽  
Combustion Technology ◽  
Further Development

Recently a considerable effort was made to understand the gas- and thermodynamics of wave rotor combustion technology. Pressure-gain combustors potentially have superior performance over conventional combustors due to their unsteady flow behaviour. Wave rotor combustion provides semi-constant volume combustion and could be integrated in the steady-flow gas turbine. However, a feasibility study to assess the economical and environmental aspects of this concept has not been conducted for short-range missions. Preliminary Multidisciplinary Design Framework was developed to assess novel and radical engine cycles. The tool comprises modules to evaluate noise, emissions and environmental impact. Uncertainty can be accounted for with Monte Carlo simulation. The geared turbofan with constant volume combustor is simulated and benchmarked against a baseline geared turbofan engine. Results indicate that the former complies with CAEP/6 and FAR Part 36 regulations for noise and emissions. Furthermore, acquisition cost of the engine is higher, but engine direct operating cost decreases by 25.2%. The technology requires further development to meet future noise and emissions requirements.

Numerical Characterization of a Novel Staged Combustion Concept Applied to Oxy-Fuel Carbon Capture Technology

2011 ◽  
Author(s):  
Adrian Goanta ◽  
Jan-Peter Bohn ◽  
Maximilian Blume ◽  
Xinmeng Li ◽  
Hartmut Spliethoff
Keyword(s):  
Flue Gas ◽  
Carbon Capture ◽  
Co2 Concentration ◽  
Operating Conditions ◽  
Major Drawback ◽  
Numerical Characterization ◽  
Recent Developments ◽  
Combustion Technology ◽  
Experimental Values

In oxy-combustion the fuel is burnt in a mixture of oxygen and recirculated flue gas to keep the temperature inside the furnace to levels similar to conventional combustion. This eliminates the atmospheric nitrogen from the process, leading to a flue gas consisting mainly of carbon dioxide and water vapor. Further on, the CO2 can be separated for storage purposes. A major drawback of the conventional oxy-fuel combustion technology consists in the high amount of flue gas that has to be recirculated in order to control the temperature level inside the furnace. A novel oxy-fuel firing concept based on a combination of pulverized coal burners operating under non-stoichiometric conditions is investigated as a solution for lowering the necessary flue gas recirculation rate, while keeping the temperature inside the furnace at feasible levels. This paper presents a numerical analysis of the most relevant aspects for this new firing concept, such as process specifics and limitations, burner design criteria, aerodynamic characterization of the near burner zone, flame ignition and temperature. First the process is defined via thermodynamic calculations which are necessary to establish the operating conditions and to generate sets of parameters for the design phase of the burners. Subsequently the parameters generated in the first phase are used as boundary conditions for the design of the burners via CFD simulations. The CFD code used in this study is updated for oxy-firing conditions with the recent developments in terms of gas phase reactions, char conversion modeling and radiative heat transfer in high temperature atmospheres with elevated CO2 concentration. Additionally, the most relevant aspects regarding the validation of the CFD code against in-flame experimental values are presented and discussed. The simulations show good agreement with the averaged experimental data collected along the flame centerline.

Application of the Geared Turbofan With Constant Volume Combustor on Short-Range Aircraft: A Feasibility Study

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Ramón F. Colmenares Quintero ◽  
Rob Brink ◽  
Stephen Ogaji ◽  
Pericle Pilidis ◽  
Juan C. Colmenares Quintero ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Short Range ◽  
Flow Behavior ◽  
Operating Cost ◽  
Constant Volume ◽  
Superior Performance ◽  
Wave Rotor ◽  
Environmental Aspects ◽  
Combustion Technology ◽  
Further Development

Recently a considerable effort was made to understand the gas- and thermodynamics of wave rotor combustion technology. Pressure-gain combustors potentially have superior performance over conventional combustors due to their unsteady flow behavior. Wave rotor combustion provides semiconstant volume combustion and could be integrated in the steady-flow gas turbine. However, a feasibility study to assess the economical and environmental aspects of this concept has not been conducted for short-range missions. Preliminary multidisciplinary design framework was developed to assess novel and radical engine cycles. The tool comprises modules to evaluate noise, emissions, and environmental impact. Uncertainty can be accounted for with Monte Carlo simulation. The geared turbofan with constant volume combustor is simulated and benchmarked against a baseline geared turbofan engine. Results indicate that the former complies with CAEP/6 and FAR Part 36 regulations for noise and emissions. Furthermore, the acquisition cost of the engine is higher, but the engine direct operating cost decreases by 25.2%. The technology requires further development to meet future noise and emission requirements.

Fuel and Combustion System Capabilities of GE’s F and HA Class Gas Turbines

2017 ◽  
Author(s):  
Jeffrey Goldmeer ◽  
William York ◽  
Paul Glaser
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Electrical Power ◽  
Combined Cycle ◽  
Combustion System ◽  
Digital Twin ◽  
Fuel Flexibility ◽  
Natural Gas Prices ◽  
Recent Developments ◽  
Combustion Technology

The world is currently undergoing a shift in the power industry with an increase in the amount of electrical power being generated from natural gas. This is being driven, in part, by the increase in availability of natural gas derived from shale gas and the reduction in global natural gas prices. In parallel, there is a second trend; a shift of new gas turbines installations to higher efficiency F and HA-class gas turbine combined cycle platforms. Supporting these industry trends, GE’s DLN 2.6+ combustion system, which is available for the 7F, 9F, 7HA, and 9HA gas turbines offers a high degree of operational and fuel flexibility. The latest evolution of this combustion technology for GE’s 7F gas turbines has been commissioned on 25 units, including new units and upgrades to existing turbines. The increased fuel and operational flexibility of this system is aided by GE’s advanced control systems that includes a high fidelity digital twin. This paper details recent developments of the DLN 2.6+ combustion system as well as validation examples for both the DLN 2.6+ and the digital twin controls system.

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Filaments and membranes in the mitotic apparatus

1983 ◽  
Vol 41 ◽  
pp. 544-547
Author(s):  
Kent McDonald
Keyword(s):  
Intermediate Filaments ◽  
Mitotic Spindle ◽  
Mitotic Apparatus ◽  
Light Microscope Level ◽  
Microtubule Associated Proteins ◽  
Recent Developments ◽  
Associated Proteins ◽  
Force Generator ◽  
Spindle Function ◽  
Antibody Technology

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.

Software pattern recognition applied to nanodiffraction patterns from a STEM instrument

1986 ◽  
Vol 44 ◽  
pp. 694-695
Author(s):  
G.Y. Fan ◽  
J.M. Cowley
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
Computer Software ◽  
Processing System ◽  
Light Level ◽  
Host Computer ◽  
Low Light ◽  
Image Processing System ◽  
Recent Developments ◽  
On Line

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.

High-resolution microscopy of twin boundaries in gold

1987 ◽  
Vol 45 ◽  
pp. 260-261
Author(s):  
William Krakow ◽  
David A. Smith
Keyword(s):  
High Resolution ◽  
Specimen Preparation ◽  
Gold Films ◽  
Boundary Area ◽  
Transmission Electron ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Microscopy ◽  
Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

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