Study on the Fuel Flexibility of a Microgas Turbine Combustor Burning Different Mixtures of H2, CH4, and CO2

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Antonio Di Nardo ◽  
Alessandro Bo ◽  
Giorgio Calchetti ◽  
Eugenio Giacomazzi ◽  
Giuseppe Messina
Keyword(s):  
Laminar Flame ◽  
Fuel Mixture ◽  
Combustion Efficiency ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Fuel Flexibility ◽  
Partial Load ◽  
3D Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Wobbe Index

Abstract The aim of this work is to analyze the behavior of the fuel flexible Ansaldo ARI100 T2 microgas turbine (MGT) combustor operated with mixtures having different H2, CH4, and CO2 concentrations. This combustor is going to be installed on an in-house modified Turbec T100 P MGT, which is originally equipped with a methane fired combustor. In a previous study, the combustor was simulated with a H2 enriched syngas, whose Wobbe index was within the limits imposed by the syngas supply system of an Ansaldo test bench. In this study, this constraint has been removed to gain a deeper understanding on how the fuel mixture properties (composition, heating value, and laminar flame speed) affect combustor performance. To this end, a series of Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) simulations have been carried out on the full-scale 3D geometry of the combustion chamber, at full and partial load (50%), evaluating for each case combustion efficiency as well as NOx and CO emissions.

scholarly journals Probabilistic Performance Analysis of Eroded Compressor Blades

2005 ◽  
Author(s):  
A. Kumar ◽  
P. B. Nair ◽  
A. J. Keane ◽  
S. Shahpar
Keyword(s):  
Probabilistic Analysis ◽  
Surrogate Model ◽  
Uncertainty Propagation ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Compressor Blades ◽  
Geometry Modeling ◽  
Blade Section ◽  
Computational Fluid Dynamics Cfd ◽  
Fan Blade

This paper presents a probabilistic analysis of the effect of erosion on the performance of compressor fan blades. A realistic parametric CAD model is developed to represent eroded blades. Design of Experiments (DOE) techniques are employed to generate a set of candidate points, which are combined with a parametric geometry modeling and grid generation routine to produce a hybrid mesh. A multigrid Reynolds-Averaged Navier Stokes (RANS) solver HYDRA with Spalart Allmaras turbulence model is used for Computational Fluid Dynamics (CFD) simulations. The data generated is used to create a surrogate model for efficient uncertainty propagation. This method is applied to a typical Rolls Royce compressor fan blade section. Monte Carlo Simulation, using the surrogate model, is executed for the probabilistic analysis of the compressor fan blade. Results show upto 5% increase in pressure loss for the eroded compressor fan blades.

Evaluation of Aerodynamic Characteristics of Mega-Yacht Superstructures by CFD Simulations

2020 ◽  
Vol 36 (04) ◽  
pp. 259-270
Author(s):  
Ahmet Ziya Saydam ◽  
Serhan Gokcay ◽  
Mustafa Insel
Keyword(s):  
Aerodynamic Characteristics ◽  
Temperature Gradients ◽  
Time Dependent ◽  
Navier Stokes ◽  
Noise Generation ◽  
Velocity Data ◽  
Cfd Simulations ◽  
Recent Developments ◽  
Computational Fluid Dynamics Cfd

Air wake distribution around the superstructure of a mega-yacht is a key concern for the designer because of various reasons such as comfort expectations in recreational deck areas, self-noise generation, air pollution and temperature gradients due to exhaust interactions, and safety of helicopter operations such as landing/take off and hovering. The Reynolds-averaged Navier-Stokes (RANS) technique in computational fluid dynamics (CFD) is frequently used in studies on mega-yacht hydrodynamics and aerodynamics with satisfactory results. In this article, a case study is presented for the utilization of CFD in a mega-yacht's superstructure design. The flow field in recreational open areas has been analyzed for the increase in velocity due to the existence of the superstructure. A reduction in self-noise of the mast structure has been aimed by reducing flow separation and vorticity. Time-dependent velocity data obtained with scale-resolving simulations are presented for the evaluation of helicopter landings. The capabilities and limitations of the RANS technique are discussed along with recent developments in modeling approaches.

scholarly journals The Efficient Application of an Impulse Source Wavemaker to CFD Simulations

2019 ◽  
Author(s):  
Pál Schmitt ◽  
Christian Windt ◽  
Josh Davidson ◽  
John V. Ringwood ◽  
Trevor Whittaker
Keyword(s):  
Shallow Water ◽  
Source Function ◽  
Cfd Simulation ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wide Range ◽  
Rans Models ◽  
Hydrodynamic Processes ◽  
Computational Fluid Dynamics Cfd ◽  
Shallow Water Models

Computational Fluid Dynamics (CFD) simulations, based on Reynolds Averaged Navier Stokes (RANS) models, are a useful tool for a wide range of coastal and offshore applications, providing a high fidelity representation of the underlying hydrodynamic processes. Generating input waves in the CFD simulation is performed by a numerical wavemaker (NWM), with a variety of different NWM methods existing for this task. While NWMs, based on impulse source methods, have been widely applied for wave generation in depth averaged, shallow water models, they have not seen the same level of adoption in the more general RANS based CFD simulations, due to difficulties in relating the required impulse source function to the resulting free surface elevation for non-shallow water cases. This paper presents an implementation of an impulse source wavemaker, which is able to self-calibrate the impulse source function to produce a desired wave series in deep or shallow water at a specific point in time and space. Example applications are presented, for a numerical wave tank (NWT), based on the opensource CFD software OpenFOAM, for wave packets in deep and shallow water, highlighting the correct calibration of phase and amplitude. Also, the suitability for cases requiring very low reflection from NWT boundaries is demonstrated. Possible issues in the use of the method are discussed and guidance for good application is given.

Comparison of the CFD Results to PIV Measurements in Kinematics of Spilling and Plunging Breakers

2020 ◽  
Author(s):  
Bülent Düz ◽  
Jule Scharnke ◽  
Rink Hallmann ◽  
Jan Tukker ◽  
Siddhant Khurana ◽  
...  
Keyword(s):  
High Speed ◽  
Piecewise Linear ◽  
Sampling Rate ◽  
Navier Stokes ◽  
Computational Domain ◽  
Cfd Simulations ◽  
High Sampling Rate ◽  
Interface Reconstruction ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Abstract The kinematics under spilling and plunging breakers are investigated using both experimental and numerical methods. In a modular laboratory flume, the breakers were generated using dispersive focusing, and the kinematics underneath them were measured utilizing the Particle Image Velocimetry (PIV) technique. Using the state-of-art high-speed video cameras and lasers, the kinematics were measured at a high sampling rate without needing phase-locked averaging. Afterwards, Computational Fluid Dynamics (CFD) simulations were carried out for comparison purposes. These simulations were run in single-phase using a finite-volume based Navier-Stokes solver with a piecewise-linear interface reconstruction scheme. The spilling and plunging breakers from the measurements were reconstructed in the computational domain using an iterative scheme. As a result a good match with the measured waves was obtained in the simulations. Results indicate that even though measured kinematics are somewhat higher than the simulated ones especially in the spilling and overturning regions, the CFD simulations can accurately capture the relevant details of the flow and produce reasonably accurate kinematics in comparison with the PIV results.

A Study of Wind Turbine Wakes in Complex Terrain Through RANS Simulation and SCADA Data

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Davide Astolfi ◽  
Francesco Castellani ◽  
Ludovico Terzi
Keyword(s):  
Wind Turbine ◽  
Complex Terrain ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Test Case ◽  
Cfd Simulations ◽  
Relevant Role ◽  
Computational Fluid Dynamics Cfd

This work deals with wind turbine wakes in complex terrain. The test case is a cluster of four 2.3 MW wind turbines, sited in a very complex terrain. Their performances are studied through supervisory control and data acquisition (SCADA) data, suggesting a relevant role of the terrain in distorting the wake of the upstream turbines. The experimental evidences stimulate a deeper comprehension through numerical modeling: computational fluid dynamics (CFD) simulations are run, using the Reynolds-averaged Navier–Stokes (RANS) formulation. A novel way of elaborating the output of the simulations is proposed, providing metrics for quantifying the three-dimensional (3D) evolution of the wake. The main outcome of the numerical analysis is that the terrain distorts the wind flow so that the wake profile is severely asymmetric with respect to the lateral displacement. Further, the role of orography singularities is highlighted in dividing the wake front, thus inducing faster wake recovery with respect to flat terrain. This interpretation is confirmed by SCADA data analysis.

Numerical Analysis of Lateral Skirts Performance on Drag Force of a Semi-Trailer Truck

2018 ◽  
Author(s):  
M. Lateb ◽  
H. Fellouah
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Experimental Results ◽  
Navier Stokes ◽  
Force Parameter ◽  
Cfd Simulations ◽  
Total Drag ◽  
Computational Fluid Dynamics Cfd ◽  
Induced Flow ◽  
Relative Errors

This work performs computational fluid dynamics (CFD) simulations using a transient URANS (unsteady Reynolds averaged Navier–Stokes) turbulence model to investigate the influence of lateral skirts — located in the lower part of a semitrailer truck — in terms of reducing the total drag force and fuel consumption savings. The total drag force values are calculated for three semi-trailer trucks speeds (i.e. 60, 70 and 100 km/h), compared, and then validated against experimental results carried out in a wind tunnel reduced model scale (1:28). The relative errors of the aerodynamic drag force parameter are assessed in order to quantify the accuracy and the reliability of the numerical modeling results with regard to the experimental results. In addition, the flow pattern around the semi-trailer truck is then investigated to determine how the induced flow field is channeled, and where the recirculating zones are modified and developed when using the additional skirt device.

scholarly journals A Data Augmentation-Based Technique for Deep Learning Applied to CFD Simulations

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1843
Author(s):  
Alvaro Abucide-Armas ◽  
Koldo Portal-Porras ◽  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Adrian Teso-Fz-Betoño
Keyword(s):  
Fluid Dynamics ◽  
Turbulent Flows ◽  
Input Data ◽  
Data Augmentation ◽  
Stokes Equations ◽  
Computational Cost ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd

The computational cost and memory demand required by computational fluid dynamics (CFD) codes simulations can become very high. Therefore, the application of convolutional neural networks (CNN) in this field has been studied owing to its capacity to learn patterns from sets of input data, which can considerably approximate the results of the CFD simulations with relative low errors. DeepCFD code has been taken as a basis and with some slight variations in the parameters of the CNN, while the net is able to solve the Navier–Stokes equations for steady turbulent flows with variable input velocities to the domain. In order to acquire extensive input data to the CNN, a data augmentation technique, which considers the similarity principle for fluid dynamics, is implemented. As a consequence, DeepCFD is able to learn the velocities and pressure fields quite accurately, speeding up the time-consuming CFD simulations.

scholarly journals Uji daya mesin diesel dengan hot EGR menggunakan bahan bakar campuran biosolar, metanol kadar rendah, dan jatropha

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Yafid Effendi ◽  
Syaiful Syaiful
Keyword(s):  
Diesel Engine ◽  
Fuel Mixture ◽  
Combustion Efficiency ◽  
Biodiesel Fuel ◽  
Brake Power ◽  
Heavy Equipment ◽  
Fuel Flexibility ◽  
Low Levels ◽  
Gas Recirculation ◽  
Motorized Vehicles

Motorized vehicles that are very suitable for transportation and heavy equipment vehicles are diesel engines, because their high combustion efficiency, reliability, fuel flexibility, and low fuel consumption make diesel widely used in several countries. The purpose of this study was to determine the effect of using a mixture of biosolar fuels, low levels of methanol and jatropha on power in a diesel engine using the hot Exhaust Gas Recirculation (EGR) system. This study uses an experimental method, using a 4JB1 diesel engine, the percentage of biodiesel fuel mixture, low levels of methanol and jatropha, Low Purity Methanol has a moisture content of 24.88%. The ratio of biosolar mixture, methanol and jatropha used are D85LPM5J10, D80LPM10J10, D75LPM15J10, D75LPM5J20, D70LPM10J20, D65LPM15J20, D65LPM5J30, D60LPM10J30 and D55LPM15J30. EGR openings vary from 0%, 25%, 50%, 75% and 100%. The test is carried out at a constant speed of 2000 rpm and is given a load of 25%, 50%, 75% and 100%. This study uses a dynamite brand Land & Sea dynamite. The results of this study are the use of EGR resulted in increasing the value of brake power. The effect of the fuel mixture causes the value of brake power tends to fall compared to D100. When using D85LPM5J10, D80LPM10J10, D70LPM10J20 and D55LPM15J30 at low loads (25%) there is an increase in power by 12.03%, 7.50%, 5.01%, and 5.97%. Keywords: Power, Engine, Diesel, LPM, Jatropha, EGR.

Scale Effects on Ship Maneuverability Using RANS

2018 ◽  
Author(s):  
Motoki Araki
Keyword(s):  
Cfd Simulation ◽  
Scale Effects ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Ship Maneuvering ◽  
Ship Maneuverability ◽  
Computational Fluid Dynamics Cfd ◽  
Rudder Angle ◽  
Maneuvering Simulations

Predicting ship maneuverability is one of the important topics in ship engineering. However because of the huge difference between model and full scale Reynolds number (Re), it is almost impossible to predict full scale ship maneuverability using conventional methods such as model test. On the other hands, with the developments of computational technologies and computational fluid dynamics (CFD) techniques, CFD simulations are widely applied on ship maneuvering problems (e.g. Stern et al., 2011). Moreover some of the researchers start the CFD simulation with full scale Re especially on propulsion problems (e.g. Tezdogan et al., 2015) which showing reasonable results. Therefore, in this paper, captive maneuvering simulations (rudder angle test) in model/full scale Re on KVLCC2 are carried out using Reynolds-averaged Navier–Stokes (RANS) solver NAGISA (Ohashi et al., 2014) with the overset gird method UP_GRID (Kodama et al., 2012). And the results between model and full scale simulations are compared in maneuvering coefficients and flow field to reveal the scale effect on ship maneuverability.

CFD Simulations of Self-Propulsion and Turning Circle Maneuver up to 90º of Ship in Waves

2020 ◽  
pp. 1-14
Author(s):  
Cong Liu ◽  
Jianhua Wang ◽  
Decheng Wan
Keyword(s):  
Fluid Dynamics ◽  
Navier Stokes ◽  
Test Case ◽  
Computational Domain ◽  
Cfd Simulations ◽  
Experimental Fluid Dynamics ◽  
Free Surfaces ◽  
Overset Grids ◽  
Propulsion Performance ◽  
Computational Fluid Dynamics Cfd

In the present work, a Reynolds-Averaged Navier-Stokes (RANS)-overset method is used to numerically investigate self-propulsion and turning circle maneuver in waves for a container ship. A computational fluid dynamics (CFD) solver naoe-FOAM-SJTU is used for the numerical computations of the fully appended Duisburg Test Case ship model. Overset grids are used to handle the motions of the ship hull appended with the propeller and the rudder. Open source toolbox waves2Foam is used to prevent wave reflection in the computational domain. The current numerical method is validated by comparing the ship speed in the self-propulsion case between CFD and Experimental Fluid Dynamics (EFD). Predicted ship 6-DOF motions, hydrodynamic forces, free surfaces, and inflow of the propeller are presented. The propulsion characteristic is mainly studied. Assuming the thrust identification method works even in unsteady conditions, the wake fraction and propulsion efficiency are discussed. The effect of orbital motion of water particle and ship motion on the propulsion performance are identified. In conclusion, the present RANS-overset method is a reliable approach to directly simulate self-propulsion and turning circle maneuver in waves.

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