Liquid Fuel Spray Characterization for the Design of the Dual-Fuel PGT10B Combustor

2001 ◽  
Author(s):  
F. A. Tap ◽  
R. Modi ◽  
J. P. Van Buijtenen
Keyword(s):  
Liquid Film ◽  
Gas Turbine ◽  
Large Scale ◽  
Drop Size ◽  
Numerical Study ◽  
Fuel Spray ◽  
Small Scale ◽  
Dual Fuel ◽  
Test Results ◽  
Liquid Concentration

The Dry Low NOx (DLN) silo combustor of the Nuovo Pignone PGT10B gas turbine is being redesigned to meet Dual-Fuel capability. A prototype with specially designed fuel injectors, placed on airfoil-shaped elements, was tested at cold conditions (using water instead of Diesel fuel) to map the spray mass distribution at the premixer exit. The resulting profile showed high concentrations of liquid near the premixer centerline and on the premixer wall. Parallel to this test, a small-scale experimental and numerical study was made of a single atomizer of the fuel system, placed in cross flow position. This small-scale study was launched in order to gain insight in the behavior of the spray, as well as to assess the relative importance of spray modeling parameters. The PDPA experiments and 2D CFD simulations of these experiments showed fair agreement on the average drop size distribution and drop size-velocity correlation. The flow visualization also revealed liquid film formation on the surface of the airfoil, behind the injector, due to the low atomization pressure differential at cold conditions. Using this modeling experience, the spray patternation test with the prototype combustor has been modeled using an existing 3D CFD model of the premixer. The model also showed high liquid concentration on the wall, but not near the centerline. From the results of the small-scale study it is concluded that the measured high concentration near the premixer centerline is not a result of the flow field. It is assumed that in the complete assembly the liquid film from the injector vanes accumulates on the center body, resulting in a high liquid concentration downstream on the premixer centerline. Overall, the application of CFD analyses on the tests performed proved to be a very useful tool to evaluate the test results. The modeling experience identified the important factors in modeling the fuel spray in a gas turbine environment, but further evolution of computer resources is required before large-scale test results will be reproducible with CFD models.

A numerical study of the transition of jet diffusion flames

1990 ◽  
Vol 431 (1882) ◽  
pp. 301-314 ◽  
Keyword(s):  
Reynolds Number ◽  
Diffusion Coefficient ◽  
Large Scale ◽  
Numerical Study ◽  
Small Scale ◽  
Surface Model ◽  
Flame Surface ◽  
Transition Mechanism ◽  
Air Stream ◽  
Scale Fluctuation

A numerical study on the transition from laminar to turbulent of two-dimensional fuel jet flames developed in a co-flowing air stream was made by adopting the flame surface model of infinite chemical reaction rate and unit Lewis number. The time dependent compressible Navier–Stokes equation was solved numerically with the equation for coupling function by using a finite difference method. The temperature-dependence of viscosity and diffusion coefficient were taken into account so as to study effects of increases of these coefficients on the transition. The numerical calculation was done for the case when methane is injected into a co-flowing air stream with variable injection Reynolds number up to 2500. When the Reynolds number was smaller than 1000 the flame, as well as the flow, remained laminar in the calculated domain. As the Reynolds number was increased above this value, a transition point appeared along the flame, downstream of which the flame and flow began to fluctuate. Two kinds of fluctuations were observed, a small scale fluctuation near the jet axis and a large scale fluctuation outside the flame surface, both of the same origin, due to the Kelvin–Helmholtz instability. The radial distributions of density and transport coefficients were found to play dominant roles in this instability, and hence in the transition mechanism. The decreased density in the flame accelerated the instability, while the increase in viscosity had a stabilizing effect. However, the most important effect was the increase in diffusion coefficient. The increase shifted the flame surface, where the large density decrease occurs, outside the shear layer of the jet and produced a thick viscous layer surrounding the jet which effectively suppressed the instability.

scholarly journals Illumination Normalization Algorithm Combination Analysis in Face Recognition

2017 ◽  
Vol 9 (3) ◽  
pp. 334-339
Author(s):  
Rokas Semėnas
Keyword(s):  
Face Recognition ◽  
Large Scale ◽  
Real Life ◽  
Direct Approach ◽  
Small Scale ◽  
Test Results ◽  
Illumination Normalization ◽  
Recognition Algorithms ◽  
Life Problems

Face recognition programs have many practical usages in various fields, such as security or entertainment. Existing recognition algorithms must deal with various real life problems – mainly with illumination. In practice, illumination normalization models are often used only for Small-scale futures extraction, ignoring Large-scale features. In this article, new and more direct approach to this problem is offered, used algorithms and test results are given.

scholarly journals The Development of Nervous Problem Based Modulewith Character Conservation for Nervous System Materials in the Senior High School

2018 ◽  
Vol 7 (3) ◽  
pp. 298-304
Author(s):  
Reefa Qudsiya ◽  
Lisdiana Lisdiana ◽  
Nugrahaningsih WH
Keyword(s):  
Nervous System ◽  
Product Design ◽  
Large Scale ◽  
Small Scale ◽  
Test Results ◽  
Research Subjects ◽  
Teaching Materials ◽  
Valid Test ◽  
Readability Test ◽  
Positive Results

Nervous system teaching materials available in schools do not contain scientific-related content as mandated by the 2013 curriculum. In addition, teaching materials also do not contain student character reinforcement content. The purpose of this study is to develop “Nervous Problem Based Module with a  Conservation Character” as a nervous system learning supplement. This type of research is Research and Development (R&D) using ten steps, namely identification of potential and problems, data collection, product design, product design validation, product design revisions, small scale trials, product revision I, large scale trials, product revision II, and final products. The research subjects were students of class XI of SMA N 1 Bae Kudus. Nervous Problem Based Module with a  Conservation Character  tested the feasibility, readability, and effectiveness. Feasibility tests obtained very valid results. Readability test results were very valid. Test effectiveness by applying  Nervous Problem Based Module with a  Conservation Character in learning, obtained effective results and can be used in learning. The insertion of the conservation character reinforcement in the module gives positive results on the character of students. It can be concluded that “Nervous Problem Based Module with a Conservation Character” is decent and effectively applied in the nervous system learning.

Experimental and numerical study on a novel ribbed bracing system

2017 ◽  
Vol 21 (9) ◽  
pp. 1349-1360
Author(s):  
Ali Akbar Golafshani ◽  
Soheil Fallah ◽  
Mohammad Amin Sahafipourfard ◽  
Ali Arzeytoon ◽  
Vahab Toufigh
Keyword(s):  
Numerical Study ◽  
Absorption Capacity ◽  
Small Scale ◽  
Test Results ◽  
Residual Drift ◽  
Numerical Studies ◽  
Numerical Assessment ◽  
Story Drift ◽  
Bracing System ◽  
Length Reduction

In this article, the ribbed bracing system is proposed and evaluated through experimental and numerical studies. Ribbed bracing system is composed of a supplemental part with ribbed interfaces that is attached to a brace member and allows for its free length reduction to prevent the development of compressional forces responsible for buckling of the brace. Ribbed bracing system provides two different mechanisms: completely closed ribbed bracing system and improved-centering ribbed bracing system which are validated, in this study, through design, fabrication, and testing of small-scale specimens subjected to cyclic quasi-static loading. As verified by the test results, in improved-centering ribbed bracing system, nearly all compressive deformations are resisted through a self-centering mechanism; thus, smaller residual drift and energy absorption capacity are provided. In contrast, completely closed ribbed bracing system is ideal for maximizing the absorbed energy and minimizing the story drift while it leads to a rather large residual drift. Numerical assessment of an X-configured ribbed bracing system assembly employing the experimentally observed behavior also validates ribbed bracing system potentials for use in frame configurations.

Impact of Water on the Fatigue Performance of Large-Scale Grouted Connection Tests

2016 ◽  
Author(s):  
Peter Schaumann ◽  
Alexander Raba ◽  
Anne Bechtel
Keyword(s):  
Large Scale ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Small Scale ◽  
Test Results ◽  
Ambient Conditions ◽  
Research Project ◽  
Joint Research Project ◽  
Scale Test ◽  
The Impact

Grouted connections represent a common joining technique between substructure and foundation piles of offshore oil & gas platforms as well as of offshore wind turbines. Due to cyclic loads arising from wind and wave actions the fatigue performance of the connection has to be considered. In lattice substructures like jackets the grouted connections are located at seabed level being fully submerged during their entire lifetime. Today’s fatigue design regulations are based on investigations neglecting any influence of the surrounding water since they were conducted in dry ambient conditions. So far, only Germanischer Lloyd gives additional recommendations for submerged grouted connections. At the Institute for Steel Construction, Leibniz Universität Hannover, Germany investigations of the joint research project ‘GROWup’ focus on the fatigue performance of axially loaded grouted connections. The project is funded by the Federal Ministry for Economic Affairs and Energy (BMWi, funding sign: 0325290) and is the third project in a row dealing with grouted connections. As part of this research project, cyclic loading tests on small-scale and large-scale grouted connections with shear keys are conducted. Small-scale fatigue tests showed a reduced number of endurable load cycles for connections when tested in wet ambient conditions. However, the transferability of these findings to a larger scale was still doubtful due to unknown scale effects. Therefore, the impact of water on the fatigue performance was tested recently at large-scale grouted connections. Previous to the submerged large-scale grouted connection fatigue tests, similar test specimens were exposed to alternating loads at dry ambient conditions. Comparison of both large-scale test results under wet and dry conditions enable to estimate the influence of water on the fatigue performance of grouted connections. Reflection of the small-scale test results gives hints on the scale effect. Test preparation, test results and design recommendations are presented in the paper.

Flame Area Fluctuation Measurements in Velocity-Forced Premixed Gas Turbine Flames

2015 ◽  
Author(s):  
Alexander J. De Rosa ◽  
Janith Samarasinghe ◽  
Stephen J. Peluso ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca
Keyword(s):  
Heat Release ◽  
Gas Turbine ◽  
Heat Release Rate ◽  
Release Rate ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Small Scale ◽  
Flame Velocity ◽  
Unstable Combustion

Fluctuations in the heat release rate that occur during unstable combustion in lean premixed gas turbine combustors can be attributed to velocity and equivalence ratio fluctuations. For a fully premixed flame, velocity fluctuations affect the heat release rate primarily by inducing changes in the flame area. In this paper, a technique to analyze changes in flame area using chemiluminescence-based flame images is presented. The technique decomposes the flame area into separate components which characterize the relative contributions of area fluctuations in the large scale structure and the small scale wrinkling of the flame. The fluctuation in the wrinkled area of the flame which forms the flame brush is seen to dominate its response in the majority of cases tested. Analysis of the flame area associated with the large scale structure of the flame resolves convective perturbations that move along the mean flame position. Results are presented that demonstrate the application of this technique to both single-nozzle and multi-nozzle flames.

Development of a high-efficiency and long-life 500W class H-Darrieus-type vertical axis wind turbine (VAWT) system using skin-spar-foam sandwich composite structure

2013 ◽  
Vol 20 (4) ◽  
pp. 383-394
Author(s):  
Changduk Kong ◽  
Haseung Lee
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
High Efficiency ◽  
Vertical Axis ◽  
Small Scale ◽  
Test Results ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Structural Test ◽  
The City

AbstractSince the focus on the energy crisis and environmental issues due to excessive fossil fuel consumption, wind power has been considered as an important renewable energy source. Recently, several megawatt-class large-scale wind turbine systems have been developed in some countries. Even though the large-scale wind turbine can effectively produce electrical power, the small-scale wind turbine has been continuously developed due to some advantages; for instance, it can be easily built at a low cost without any limitation of location, i.e., even in the city. In case of small-scale wind turbines, the vertical axis wind turbine (VAWT) is used in the city despite having a lower efficiency than the horizontal axis wind turbine. Furthermore, most small-scale wind turbine systems have been designed at the rated wind speed of around 12 m/s. This aim of this work is to design a high-efficiency 500W class composite VAWT blade that is applicable to relatively low-speed regions. With regard to the aerodynamic design of the blade, parametric studies are carried out to decide an optimal aerodynamic configuration. The aerodynamic efficiency and performance of the designed VAWT is confirmed by computational fluid dynamics analysis. The structural design is performed by the load case study, initial sizing using the netting rule and the rule of mixture, structural analysis using finite element method (FEM), fatigue life estimation and structural test. The prototype blade is manufactured by hand lay-up and the matched die molding. The experimental structural test results are compared with the FEM analysis results. Finally, to evaluate the prototype VAWT including designed blades, the performance test is performed using a truck to simulate various ranges of wind speeds and some measuring equipment. According to the performance evaluation result, the estimated performance agrees well with the experimental test results in all operating ranges.

scholarly journals Impact Assessment of Orography on the Extreme Precipitation Event of July 2010 over Pakistan: A Numerical Study

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Khan Muhammad Tahir ◽  
Yan Yin ◽  
Yong Wang ◽  
Zaheer A. Babar ◽  
Dong Yan
Keyword(s):  
Large Scale ◽  
Extreme Event ◽  
Numerical Study ◽  
Deep Convection ◽  
Temporal Distribution ◽  
Precipitation Event ◽  
Windward Side ◽  
Small Scale ◽  
Extreme Rainfall Event ◽  
Synoptic Conditions

The topography influences monsoon precipitation and gives rise to significant rainfall events in South Asia. The physical mechanism involved in such events includes mechanical uplifting, thermodynamics, small scale cloud processes, and large scale atmospheric circulations. The investigation into orographic precipitation is pursued by synoptic and model analysis. Deep convection occurs as warm moist airflow is channeling over steep mountains. WRF model coupled with Morrison double moment scheme is used to assess the relative impact of topography on extreme rainfall event of 26–30 July 2010 in Pakistan. Two sensitivity tests with full topography (CTL) and reduced topography by 50% (LOW) are carried out. Two distinct precipitation zones over Hindukush and Himalaya mountains are identified. The topographic changes significantly affect moisture divergence and spatial and temporal distribution of precipitation. A low level jet is created on windward side of big mountains, yielding enhanced moisture flux and instability. Eddy kinetic energy significantly changes with orographic height. Energy flux created further unstabilized atmosphere and deep convection, producing wide spread heavy rainfall in the area in Himalaya foothills. Under the set synoptic conditions, orographic orientation enhanced the moisture accumulation and deep convection, resulting in occurrence of this extreme event.

scholarly journals Development Of Guided Discovery Based Electronic Module For Chemical Lessons In Redox Reaction Materials

2021 ◽  
Vol 15 (07) ◽  
pp. 94
Author(s):  
Dewi Handayani ◽  
Elvinawati Elvinawati ◽  
Isnaeni Isnaeni ◽  
Muzanip Alperi
Keyword(s):  
Redox Reaction ◽  
Large Scale ◽  
Student Response ◽  
Small Scale ◽  
Test Results ◽  
Guided Discovery ◽  
Student Responses ◽  
The Media ◽  
The Subject ◽  
Response Percentage

This research is the development of guided discovery based electronic module that aims to know the eligibility level of e-modules and student responses to guided discovery-based electronic modules in redox reaction material. This electronic module uses the ADDIE development model. The research was conducted at one of the high schools in Bengkulu with the subject 9 students of X MIPA A Students for small scale trials and 30 students of X MIPA D Students for large scale trials. From the results of the research obtained (1) the percentage of the feasibility of e-modules on the material aspect is 86,315% while from the media aspect is 91.425% so that based on the results of validation by the E-module validator is declared very valid, (2) based on the test results of the small-scale student response percentage of 75.97 % with interesting category, while for large-scale trials of 84.48% with a very interesting category. From the results percentage, it can be concluded that e-module is suitable for use in learning. Electronic module based on guided discovery is an effective tool to help students in learning redox reaction subject. E-module can be accessed by smartphone or laptop. With this e-module, students can access the study material from everywhere without any time limitation.

Concepts for the Production of Biomass Derived Fuel Gases for Gas Turbine Applications

2000 ◽  
Author(s):  
W. Schmitz ◽  
D. Hein
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Large Scale ◽  
Biomass Conversion ◽  
Rankine Cycle ◽  
Small Scale ◽  
Pyrolysis Gas ◽  
Gas Cleaning ◽  
Mild Pyrolysis ◽  
Hot Gas Cleaning

Amongst the available alternatives of regenerative energy sources, biomass may play an important role in the future. Biomass represents stored solar energy, accessible whenever there is demand. But so far, its large potential has only been used to a small extent. This is partly due to the fact that solid biomass is a common fuel for the production of heat, but is hardly used in combined heat and power (CHP) plants. For the conversion of solid fuels, combustion in combination with a Rankine cycle is the only well established technology available today, thus acceptable net efficiencies (> 25% LHV) are only possible in complex, rather large scale plants. However, since the occurrence of biomass differs depending on region and season, and because of its low energy density and thus reduced transportability, biomass is particularly suited for decentralized applications, i.e. for the generation of heat and power (1) in the small power range. This paper discusses strategies for the integration of biomass gasification / pyrolysis and gas cleaning processes into different gas turbine schemes. Rather than reviewing all possible aspects of and concepts for the usage of biomass in gas turbine applications, this paper evaluates some key aspects (pressurization, tar removal, gas cleaning, choice of gas turbine cycle) of directly fired gas turbine concepts with regard to small scale applications. The paper shows that tar is a key problem. Especially for small scale applications solutions based on the combustion of tars, like pressurized biomass conversion in combination with hot gas cleaning, prove to be simple and efficient. This paper also compares the characteristics of integrated gasification cycles, e.g. by demonstrating difficulties connected with the integration of steam blown allothermal gasification (reforming). Furthermore, it is shown that recuperated gas turbines are well suited for highly efficient, yet simple small scale applications. Test results indicate that “mild” pyrolysis is an alternative technology for the production of comparatively clean medium heating value gases. Integrating the use of pyrolysis gas and charcoal into a simple gas turbine plant, however, can not easily be achieved.

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