The Prediction of Sauter Mean Diameter for Gas Turbine Fuel Nozzles of Different Types

1980 ◽  
Vol 102 (3) ◽  
pp. 646-652 ◽  
Author(s):  
H. C. Simmons
Keyword(s):  
Gas Turbine ◽  
Present State ◽  
State Of The Art ◽  
Prediction Equation ◽  
Published Data ◽  
Sauter Mean Diameter ◽  
Mean Diameter ◽  
Different Types

Reviewing the more important published equations for predicting SMD for various types of fuel nozzles it is pointed out that there is no universal or common approach to cover different nozzle designs. In particular there is no effort to bridge the gap between pressure-atomizers and air-atomizers, especially the air-assisted simplex nozzle. Furthermore many of the equations provide no basis for estimating the effect of dimensions which is essential in modeling. An equation is presented, based on both new and published data, which satisfies these objections, and is shown to be related to previous methods. Suggestions are made with regard to the choice of constants in the prediction equation so as to represent fairly the present state of the art.

scholarly journals Influence of Residence Time on Fuel Spray Sauter Mean Diameter (SMD) and Emissions Using Biodiesel and its Blends in a Low NOx Gas Turbine Combustor

2016 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Gordon E. Andrews
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Spray ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Gaseous Emissions ◽  
Low Carbon ◽  
Sauter Mean Diameter ◽  
Gas Turbine Combustor ◽  
Mean Diameter

Biodiesels have advantages of low carbon footprint, reduced toxic emissions, improved energy supply security and sustainability and therefore attracted attentions in both industrial and aero gas turbines sectors. Industrial gas turbine applications are more practical biodiesels due to low temperature waxing and flow problems at altitude for aero gas turbine applications. This paper investigated the use of biodiesels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) was tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure, 600K air inlet temperature and reference Mach number of 0.017&0.023. The pure WME, its blends with kerosene (B20 and B50) and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio for both Mach numbers. Sauter Mean Diameter (SMD) of the fuel spray droplets was calculated. The results showed that the WME and its blends had lower CO, UHC emissions and higher NOx emissions than the kerosene. The weak extinction limits were determined for all fuels and B100 has the lowest value. The higher air velocity (at Mach = 0.023) resulted in smaller SMDs which improved the mixing and atomizing of fuels and thus led to reductions in NOx emissions.

scholarly journals Evaluation of Atomization Characteristics of Second Generation Biodiesel Using Air Blast Atomizer

2018 ◽  
Vol 7 (4.35) ◽  
pp. 772
Author(s):  
Gopinathan Muthaiyah ◽  
Kumaran Palanisamy
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
High Viscosity ◽  
Spray Angle ◽  
Biodiesel Fuel ◽  
Sauter Mean Diameter ◽  
Evaporation Time ◽  
Air Blast ◽  
Mean Diameter ◽  
Atomization Characteristics

Biodiesel is one of the well-known renewable fuels that can be produced from organic oils and animal fats. Biodiesel fuel that meets ASTM D6751 fuel standards can replace diesel for reciprocating engine. On the other hand, biodiesel can also be considered for gas turbine application in power generation. Nevertheless, inferior properties of biodiesel such as high viscosity, density and surface tension results in inferior atomization and high emission which consequently hinders the fuel for gas turbine utilisation and generate higher emission pollutants. Therefore, this work focused on the evaluation of atomization characteristics of second generation biodiesel which is produced using microwave assisted post treatment scheme. The atomisation characteristics of second generation biodiesel was evaluated using air blast atomiser in terms of spray angle and spray length. Subsequently, numerical evaluation was performed to evaluate sauter mean diameter and droplet evaporation time of second generation biodiesel.  The results show, atomization characteristics of second generation biodiesel has improved in terms of spray angle and spray length, sauter mean diameter and shorter evaporation time compared to biodiesel which is commonly referred to as first generation biodiesel and fossil diesel.

Production of Integrally-Cast Airfoil Components for Small Gas-Turbine Engines

1962 ◽  
Author(s):  
J. H. Boyle
Keyword(s):  
Gas Turbine ◽  
Present State ◽  
Investment Casting ◽  
State Of The Art ◽  
Casting Process ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Pattern Production ◽  
Final Inspection

This paper presents a review of the progress made by the investment casting foundries in producing integrally-cast airfoil components for small gas-turbine engines. The casting process, from pattern production to the final inspection operations, is discussed in detail. Suggested dimensional tolerances, based on the present state of the art, are included. Finally, the properties and casting characteristics of various alloys commonly used for internal components are presented.

The Present State of the Art

1984 ◽  
Vol 29 (4) ◽  
pp. 344-346
Author(s):  
Peter A. Magaro
Keyword(s):  
Present State ◽  
State Of The Art

scholarly journals Multiple objects tracking in the UAV system based on hierarchical deep high-resolution network

2021 ◽  
Author(s):  
Wei Huang ◽  
Xiaoshu Zhou ◽  
Mingchao Dong ◽  
Huaiyu Xu
Keyword(s):  
High Resolution ◽  
Object Tracking ◽  
High Performance ◽  
State Of The Art ◽  
Class Imbalance ◽  
Unified Framework ◽  
Multiple Objects ◽  
Tracking Process ◽  
Objects Tracking ◽  
Different Types

AbstractRobust and high-performance visual multi-object tracking is a big challenge in computer vision, especially in a drone scenario. In this paper, an online Multi-Object Tracking (MOT) approach in the UAV system is proposed to handle small target detections and class imbalance challenges, which integrates the merits of deep high-resolution representation network and data association method in a unified framework. Specifically, while applying tracking-by-detection architecture to our tracking framework, a Hierarchical Deep High-resolution network (HDHNet) is proposed, which encourages the model to handle different types and scales of targets, and extract more effective and comprehensive features during online learning. After that, the extracted features are fed into different prediction networks for interesting targets recognition. Besides, an adjustable fusion loss function is proposed by combining focal loss and GIoU loss to solve the problems of class imbalance and hard samples. During the tracking process, these detection results are applied to an improved DeepSORT MOT algorithm in each frame, which is available to make full use of the target appearance features to match one by one on a practical basis. The experimental results on the VisDrone2019 MOT benchmark show that the proposed UAV MOT system achieves the highest accuracy and the best robustness compared with state-of-the-art methods.

scholarly journals Fighting Together against the Pandemic: Learning Multiple Models on Tomography Images for COVID-19 Diagnosis

AI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 261-273
Author(s):  
Mario Manzo ◽  
Simone Pellino
Keyword(s):  
Network Architecture ◽  
State Of The Art ◽  
Ensemble Classification ◽  
Effective Vaccine ◽  
Rt Pcr ◽  
Neural Network Architecture ◽  
Experimental Phase ◽  
Different Types ◽  
Polymerase Chain ◽  
Better Than

COVID-19 has been a great challenge for humanity since the year 2020. The whole world has made a huge effort to find an effective vaccine in order to save those not yet infected. The alternative solution is early diagnosis, carried out through real-time polymerase chain reaction (RT-PCR) tests or thorax Computer Tomography (CT) scan images. Deep learning algorithms, specifically convolutional neural networks, represent a methodology for image analysis. They optimize the classification design task, which is essential for an automatic approach with different types of images, including medical. In this paper, we adopt a pretrained deep convolutional neural network architecture in order to diagnose COVID-19 disease from CT images. Our idea is inspired by what the whole of humanity is achieving, as the set of multiple contributions is better than any single one for the fight against the pandemic. First, we adapt, and subsequently retrain for our assumption, some neural architectures that have been adopted in other application domains. Secondly, we combine the knowledge extracted from images by the neural architectures in an ensemble classification context. Our experimental phase is performed on a CT image dataset, and the results obtained show the effectiveness of the proposed approach with respect to the state-of-the-art competitors.

scholarly journals Heavy ion driver for fast ignition

2002 ◽  
Vol 20 (4) ◽  
pp. 595-597 ◽  
Author(s):  
D.G. KOSHKAREV
Keyword(s):  
Present State ◽  
State Of The Art ◽  
Heavy Ion ◽  
Fast Ignition ◽  
Gain Factor ◽  
Powerful Laser ◽  
Burning Process ◽  
Actual Design ◽  
Cylindrical Target ◽  
A Performance

Recently the “fast ignition” method in the ICF problem was considered (Caruso & Pais, 1996). It allows increasing a target gain factor and raising reliability of the burning process. Since the required power of the irradiating beam in this method is unattainable for the traditional type of heavy ion driver with the energy of ions ≤10 GeV, the powerful laser is considered as a possible driver only. Here we investigate the fast ignition method for a system constituted from the directly irradiated cylindrical target and a powerful heavy ion driver of the charge-symmetric type (Koshkarev, 1993) in which the ions with energy ≈100 GeV and mass ≈200 are used. The actual design of a powerful heavy ion driver with the required characteristics is outside the purpose of this article. However some consideration will be given to exploring whether such a performance is within the realm of reasonable extrapolations of the present state of the art.

History of Mathematics in the Islamic World: The Present State of the Art

1985 ◽  
Vol 19 (1) ◽  
pp. 9-33 ◽  
Author(s):  
J. L. Berggren
Keyword(s):  
Present State ◽  
State Of The Art ◽  
History Of Mathematics ◽  
Islamic Culture ◽  
Islamic World ◽  
History Of ◽  
The Subject ◽  
Mathematical Sciences ◽  
Islamic Mathematics

In Recent Years, many discoveries in the history of Islamic mathematics have not been reported outside the specialist literature, even though they raise issues of interest to a larger audience. Thus, our aim in writing this survey is to provide to scholars of Islamic culture an account of the major themes and discoveries of the last decade of research on the history of mathematics in the Islamic world. However, the subject of mathematics comprised much more than what a modern mathematician might think of as belonging to mathematics, so our survey is an overview of what may best be called the “mathematical sciences” in Islam; that is, in addition to such topics as arithmetic, algebra, and geometry we will also be interested in mechanics, optics, and mathematical instruments.

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