scholarly journals Gas Turbine Assessment for Air Management of Pressurized SOFC/GT Hybrid Systems

2006 ◽  
Vol 4 (4) ◽  
pp. 373-383 ◽  
Author(s):  
Alberto Traverso ◽  
Aristide Massardo ◽  
Rory A. Roberts ◽  
Jack Brouwer ◽  
Scott Samuelsen
Keyword(s):  
Gas Turbine ◽  
Hybrid System ◽  
Variable Speed ◽  
Ambient Conditions ◽  
Safety Measures ◽  
Turbine Performance ◽  
Wide Range ◽  
Different Types ◽  
Transient And Steady State

This paper analyzes and compares transient and steady-state performance characteristics of different types of single-shaft turbo-machinery for controlling the air through a pressurized solid oxide fuel cell (SOFC) stack that is integrated into a SOFC/GT pressurized hybrid system. Analyses are focused on the bottoming part of the cycle, where the gas turbine (GT) has the role of properly managing airflow to the SOFC stack for various loads and at different ambient conditions. Analyses were accomplished using two disparate computer programs, which each modeled a similar SOFC/GT cycle using identical generic gas turbine performance maps. The models are shown to provide consistent results, and they are used to assess: (1) the influence of SOFC exhaust composition on expander behavior for on-design conditions, (2) the off-design performance of the bypass, bleed, and variable speed controls for various part-load conditions and for different ambient conditions; (3) the features of such controls during abrupt transients such as load trip and bypass/bleed valve failure. The results show that a variable speed microturbine is the best option for off-design operation of a SOFC/GT hybrid system. For safety measures a bleed valve provides adequate control of the system during load trip. General specifications for a radial GT engine for integration with a 550kW pressurized SOFC stack are identified, which allow operation under a wide range of ambient conditions as well as several different cycle configurations.

The Effects of Ambient Conditions on Gas Turbine Emissions—Generalized Correction Factors

1978 ◽  
Vol 100 (4) ◽  
pp. 640-646 ◽  
Author(s):  
P. Donovan ◽  
T. Cackette
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Correction Factors ◽  
Oxides Of Nitrogen ◽  
Ambient Conditions ◽  
Nitrogen Emission ◽  
Wide Range

A set of factors which reduces the variability due to ambient conditions of the hydrocarbon, carbon monoxide, and oxides of nitrogen emission indices has been developed. These factors can be used to correct an emission index to reference day ambient conditions. The correction factors, which vary with engine rated pressure ratio for NOx and idle pressure ratio for HC and CO, can be applied to a wide range of current technology gas turbine engines. The factors are a function of only the combustor inlet temperature and ambient humidity.

Gas Turbine Fouling Offshore: Correction Methodology Compressor Efficiency

2017 ◽  
Author(s):  
Stian Madsen ◽  
Lars E. Bakken
Keyword(s):  
Gas Turbine ◽  
Peak Load ◽  
Operational Experience ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Key Factors ◽  
Turbine Performance ◽  
Main Challenge ◽  
Filtration System ◽  
Compressor Efficiency

Gas turbine performance has been analyzed for a fleet of GE LM2500 engines at two Statoil offshore fields in the North Sea. Both generator drive engines and compressor driver engines have been analyzed, covering both the LM2500 base and plus configurations, as well as the SAC and DLE combustor configurations. Several of the compressor drive engines are running at peak load (T5.4 control), and the production rate is thus limited to the available power from these engines. The majority of the engines discussed run continuously without redundancy, implying that gas turbine uptime is critical for the field’s production and economy. Previous studies and operational experience have emphasized that the two key factors to minimize compressor fouling are the optimum designs of the inlet air filtration system and the water wash system. An optimized inlet air filtration system, in combination with daily online water wash (at high water-to-air ratio), are the key factors to achieve successful operation at longer intervals between offline washes and higher average engine performance. Operational experience has documented that the main gas turbine recoverable deterioration is linked to the compressor section. The main performance parameter when monitoring compressor fouling is the gas turbine compressor efficiency. Previous studies have indicated that inlet depression (air mass flow at compressor inlet) is a better parameter when monitoring compressor fouling, whereas instrumentation for inlet depression is very seldom implemented on offshore gas turbine applications. The main challenge when analyzing compressor efficiency (uncorrected) is the large variation in efficiency during the periods between offline washes, mainly due to operation at various engine loads and ambient conditions. Understanding the gas turbine performance deterioration is of vital importance. Trending of the deviation from the engine baseline facilitates load-independent monitoring of the gas turbine’s condition. Instrument resolution and repeatability are key factors for attaining reliable results in the performance analysis. A correction methodology for compressor efficiency has been developed, which improves the long term trend data for effective diagnostics of compressor degradation. Avenues for further research and development are proposed in order to further increase the understanding of the deterioration mechanisms, as well as gas turbine performance and response.

scholarly journals Historical timber as a sustainable material, Studies about Islamic architecture in Egypt

2018 ◽  
Vol 5 (1) ◽  
pp. 27
Author(s):  
Dalia Shebl Said
Keyword(s):  
Timber Structures ◽  
Natural Phenomena ◽  
Historical Buildings ◽  
Islamic Architecture ◽  
Modern Material ◽  
Sustainable Building ◽  
Wide Range ◽  
Different Types ◽  
Material Studies

<p>Wood is an old – modern material, It was and still used in a wide range in a various purposes as construction, decoration and remains the most popular material all over the world, The research provides an overview of the role of  timber as an important heritage element which forms the main characters and distinguishes features of many historical buildings in Islamic architecture and used widely in many applications, it had been played a great role in construction and structure of buildings, besides that it had been used in a beautiful purpose in different places whether indoors or outdoors use<strong> </strong>. The research presents the case studies of historical timber in different types of building in Islamic architecture which constructed from more than 1400 years ago, although the historical timber in old buildings exposed to many disasters and faced quite numbers of problems as a result of natural phenomena, man-made, humidity, and termites but it still stands proudly as a great sustain materials. The research shows how he use of timber in historical buildings as sources of inspiration and living evidence of ways of sustainable building practices the types of deterioration which appeared clearly an effect on the statue of historical timber, for that the research introduces some recommendations in the light of ICOMOS international charter “ <a href="http://www.icomos.org/en/home/179-articles-en-francais/ressources/charters-and-standards/163-principles-for-the-preservation-of-historic-timber-structures">Principles for the Preservation of Historic Timber Structures</a> 1999” that Emphasizes the necessity of taking a serious steps and clear strategy to save our heritage elements</p>

Comparison of Linear and Non-Linear Gas Turbine Performance Diagnostics

2003 ◽  
Author(s):  
Ph. Kamboukos ◽  
K. Mathioudakis
Keyword(s):  
Gas Turbine ◽  
Condition Monitoring ◽  
Theoretical Background ◽  
Diagnostic Methods ◽  
Turbine Performance ◽  
Different Types ◽  
Non Linear ◽  
Computational Procedures ◽  
Monitoring And Diagnostics ◽  
Performance Diagnostics

The features of linear performance diagnostic methods are discussed, in comparison to methods based on full non-linear calculation of performance deviations, for the purpose of condition monitoring and diagnostics. First, the theoretical background of linear methods is overviewed to establish a relationship to the principles used by non-linear methods. Then computational procedures are discussed and compared. The effectiveness of determining component performance deviations by the two types of approaches is examined, on different types of diagnostic situations. A way of establishing criteria to define whether non-linear methods have to be employed is presented. An overall assessment of merits or weaknesses of the two types of methods is attempted, based on the results presented in the paper.

Analysis of Part Electric Gas Turbine: A Novel Hybrid Propulsion Concept

2019 ◽  
Author(s):  
M. S. N. Murthy ◽  
Subhash Kumar ◽  
Sheshadri Sreedhara
Keyword(s):  
Gas Turbine ◽  
Electric Motor ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Variable Speed ◽  
Hybrid Propulsion ◽  
Design Point ◽  
Part Load ◽  
Wide Range ◽  
Efficient Option

Abstract A gas turbine engine (GT) is very complex to design and manufacture considering the power density it offers. Development of a GT is also iterative, expensive and involves a long lead time. The components of a GT, viz compressor, combustor and turbine are strongly dependent on each other for the overall performance characteristics of the GT. The range of compressor operation is dependent on the functional and safe limits of surging and choking. The turbine operating speeds are required to be matched with that of compressor for wide range of operating conditions. Due to this constrain, design for optimum possible performance is often sacrificed. Further, once catered for a design point, gas turbines offer low part load efficiencies at conditions away from design point. As a more efficient option, a GT is practically achievable in a split configuration, where the compressor and turbine rotate on different shafts independently. The compressor is driven by a variable speed electric motor. The power developed in the combustor using the compressed air from the compressor and fuel, drives the turbine. The turbine provides mechanical shaft power through a gear box if required. A drive taken from the shaft rotates an electricity generator, which provides power for the compressor’s variable speed electric motor through a power bank. Despite introducing, two additional power conversions compared to a conventional GT, this split configuration named as ‘Part Electric Gas Turbine’, has a potential for new applications and to achieve overall better efficiencies from a GT considering the poor part load characteristics of a conventional GT.

Validation of Surface Temperature Measurements on a Combustor Liner Under Full-Load Conditions Using a Novel Thermal History Paint

2016 ◽  
Author(s):  
Robert Krewinkel ◽  
Jens Färber ◽  
Martin Lauer ◽  
Dirk Frank ◽  
Ulrich Orth ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal History ◽  
Measurement Techniques ◽  
Combustion Process ◽  
Lanthanide Ions ◽  
Maximum Temperature ◽  
Oxide Ceramic ◽  
Ambient Conditions ◽  
Hot Gas ◽  
Wide Range

The ever-increasing requirements on gas turbine efficiency, which are at least partially met by increasing firing temperatures, and the simultaneous demand for reduced emissions, necessitate much more accurate calculations of the combustion process and combustor wall temperatures. Thermocouples give locally very accurate measurements of these temperatures, but there is a practical limit to the amount of measurement points. Thermal paints are another established measurement technique, but are toxic and at the same time require dedicated, short-duration tests. Thermal History Paints (THPs) provide an innovative alternative to the aforementioned techniques, but so far only a limited number of tests has been conducted under real engine conditions. THPs are similar in their chemical and physical make-up to conventional thermographic phosphors which have been successfully used in gas turbine applications for on-line temperature detection before. A typical THP comprises of oxide ceramic pigments and a water based binder. The ceramic is synthesized to be amorphous and when heated it crystallizes, permanently changing the microstructure. The ceramic is doped with lanthanide ions to make it phosphorescent. The lanthanide ions act as atomic level sensors and as the structure of the material changes, so do the phosphorescent properties of the material. By measuring the phosphorescence the maximum temperature of exposure can be determined through calibration, enabling post operation measurements at ambient conditions. This paper describes a test in which THP was applied to an impingement-cooled front panel from a combustor of an industrial gas turbine. Since this component sees a wide range of temperatures, it is ideally suited for the testing of the measurement techniques under real engine conditions. The panel was instrumented with a thermocouple and thermal paint was applied to the cold side of the impingement plate. THP was applied to the hot-gas side of this plate for validation against the other measurement techniques and to evaluate its resilience against the reacting hot gas environment. The durability and temperature results of the three different measurement techniques are discussed. The results demonstrate the benefits of THPs as a new temperature profiling technique. It is shown that the THP exhibited greater durability compared to the conventional thermal paint. Furthermore, the new technology provided detailed measurements down to millimeters indicating local temperature variations and global variations over the complete component.

Shear-Induced Microporous Nanocomposite Epoxy Thermosets (MiNET)

2020 ◽  
Author(s):  
Molla Hasan ◽  
Yogin Patel ◽  
Arielle R. Gamboa ◽  
Michael Grzenda ◽  
Valeria Saro-Cortes ◽  
...  
Keyword(s):  
Domain Size ◽  
High Shear ◽  
Ambient Conditions ◽  
Immiscible Liquids ◽  
Large Domain ◽  
Emulsion Gel ◽  
Porous Architecture ◽  
Wide Range ◽  
Different Types ◽  
Shear Mixing

<p>To create microporous nanocomposite epoxy thermosets (MiNET), a mixing pathway is demonstrated in which a bicontinuous emulsion gel (bijel) like viscous fluid is kinetically trapped by high shear mixing of immiscible liquids, surfactant, and nanoparticles. The MiNETs are prepared from common ingredients, that are widely employed in industry, including epoxy resin, vegetable oil, epoxidized soybean oil, and different types of nanoparticles such as silica, activated carbon, alumina, and zinc oxide. MiNETs prepared by the presented route are processed at ambient conditions and exhibit low shrinkage (less than 2%). Furthermore, they are suitable to erect macro- to microscale structures with high precision and various porosity. The interconnected porous architecture of MiNET is even preserved in microscale features and thus ensures the mass transport in microstructures. With facile processability and tunability of pore sizes in a wide range (~100 nm to few microns), the proposed route overcomes the two major roadblocks – difficulty in fabrication and large domain size (on the order of 5µm or larger) – of bijel-like materials to apply in catalysis, energy storage, and molecular encapsulation. </p>

Adapting the Micro-Gas Turbine Operation to Variable Thermal and Electrical Requirements

2003 ◽  
Author(s):  
Fabio Bozza ◽  
Maria Cristina Cameretti ◽  
Raffaele Tuccillo
Keyword(s):  
Gas Turbine ◽  
Thermal Cycle ◽  
Heat Recovery ◽  
Mechanical Load ◽  
Heat Recovery Boiler ◽  
Variable Speed ◽  
Micro Gas Turbine ◽  
Thermal Output ◽  
Wide Range ◽  
Component Matching

This paper examines the possibilities for a micro-gas turbine operation under a wide range of thermal and mechanical load requirements. The authors focus the attention on a partially recuperated thermal cycle based on a by-pass option towards the heat recovery boiler, in order to adapt the gas turbine operation to increasing needs of thermal output. In addition, a variable speed operation is considered as a more reliable method for decreasing the mechanical output without producing an excess in efficiency decay. The actual possibilities of the above named regulation tools are examined by an integrated procedure which involves, besides an accurate thermodynamic preliminary analysis, the component matching study and the CFD based simulation of the combustion chamber.

Comparison of Linear and Nonlinear Gas Turbine Performance Diagnostics

2005 ◽  
Vol 127 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Ph. Kamboukos ◽  
K. Mathioudakis
Keyword(s):  
Gas Turbine ◽  
Theoretical Background ◽  
Diagnostic Methods ◽  
Nonlinear Methods ◽  
Turbine Performance ◽  
Different Types ◽  
Linear And Nonlinear ◽  
Computational Procedures ◽  
Monitoring And Diagnostics ◽  
Performance Diagnostics

The features of linear performance diagnostic methods are discussed, in comparison to methods based on full nonlinear calculation of performance deviations, for the purpose of condition monitoring and diagnostics. First, the theoretical background of linear methods is reviewed to establish a relationship to the principles used by nonlinear methods. Then computational procedures are discussed and compared. The effectiveness of determining component performance deviations by the two types of approaches is examined, on different types of diagnostic situations. A way of establishing criteria to define whether nonlinear methods have to be employed is presented. An overall assessment of merits or weaknesses of the two types of methods is attempted, based on the results presented in the paper.

scholarly journals The Role of Aragonite in Producing the Microstructural Diversity of Serpulid Skeletons

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1435
Author(s):  
Olev Vinn
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Powder Diffraction ◽  
Deep Ocean ◽  
X Ray ◽  
Prismatic Structure ◽  
Wide Range ◽  
Different Types ◽  
Scanning Electron

Aragonite plays an important role in the biomineralization of serpulid polychaetes. Aragonitic structures are present in a wide range of serpulid species, but they mostly belong to one clade. Aragonitic structures are present in a wide range of marine environments, including the deep ocean. Aragonitic tube microstructures were studied using a scanning electron microscope. X-ray powder diffraction was used to identify the aragonite. Aragonite is used to build five different types of microstructures in serpulid tubes. The most common aragonitic irregularly oriented prismatic structure (AIOP) is also, evolutionarily, the most primitive. Some aragonitic microstructures, such as the spherulitic prismatic (SPHP) structure, have likely evolved from the AIOP structure. Aragonitic microstructures in serpulids are far less numerous than calcitic microstructures, and they lack the complexity of advanced calcitic microstructures. The reason why aragonitic microstructures have remained less evolvable than calcitic microstructures is currently unknown, considering their fit with the current aragonite sea conditions (Paleogene–recent).

Sign in / Sign up

Export Citation Format

Share Document