LES of the Flow and Particle Ingestion Into an Air Intake of a Jet Engine Running on the Ground

2004 ◽  
Author(s):  
Dragos Moroianu ◽  
Arne Karsllon ◽  
Laszlo Fuchs
Keyword(s):  
Flow Field ◽  
Vortex System ◽  
Compressor Blades ◽  
Mean Velocity ◽  
Jet Engine ◽  
Large Eddy ◽  
Air Intake ◽  
Ground Effects ◽  
Particle Ingestion ◽  
Good Agreement

The flow field generated by the flow into a jet engine air-intake, with near ground effects, is considered. The axial inflow in the neighborhood of the ground generates a system of unsteady vortices. Some of these vortices extend from the air-intake towards the ground. Some of these vortices are strong enough to dislocate and even lift small objects from the ground up to the air-intake. The dynamics of the vortex system makes it difficult to study the problem by standard numerical and experimental methods. The dynamics of the vortices can be captured by using Large Eddy Simulations (LES), which is used here to enhance the understanding of the dynamics of the flow field. The computed flow field is used also to assess the ingestion of particles into the air-intake. It is shown that particles of several mm sizes can be ingested into the jet engine. This in turn may result in enhanced erosion of the compressor blades. The results of the computations in terms of mean velocity field have been compared to experimental data. These results are in good agreement with the experiments.

Large-Eddy and Unsteady Reynolds-Averaged Navier-Stokes Simulations of an Axial Flow Pump for Cardiac Support

2017 ◽  
Author(s):  
Benjamin Torner ◽  
Sebastian Hallier ◽  
Matthias Witte ◽  
Frank-Hendrik Wurm
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Pressure Head ◽  
Damage Parameter ◽  
Ventricular Assist Devices ◽  
Navier Stokes ◽  
Mean Velocity ◽  
Blood Damage ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

The use of implantable pumps for cardiac support (Ventricular Assist Devices) has proven to be a promising option for the treatment of advanced heart failure. Avoiding blood damage and achieving high efficiencies represent two main challenges in the optimization process. To improve VADs, it is important to understand the turbulent flow field in depth in order to minimize losses and blood damage. The application of the Large-eddy simulation (LES) is an appropriate approach to simulate the flow field because turbulent structures and flow patterns, which are connected to losses and blood damage, are directly resolved. The focus of this paper is the comparison between an LES and an Unsteady Reynolds-Averaged Navier-Stokes simulation (URANS) because the latter one is the most frequently used approach for simulating the flow in VADs. Integral quantities like pressure head and efficiency are in a good agreement between both methods. Additionally, the mean velocity fields show similar tendencies. However, LES and URANS show different results for the turbulent kinetic energy. Deviations of several tens of percent can be also observed for a blood damage parameter, which depend on velocity gradients. Possible reasons for the deviations will be investigated in future works.

Numerical laser beam propagation using large eddy simulation of a jet engine flow field

2015 ◽  
Vol 54 (08) ◽  
pp. 1 ◽  
Author(s):  
Markus Henriksson ◽  
Lars J. Sjöqvist ◽  
Oskar Parmhed ◽  
Christer Fureby
Keyword(s):  
Flow Field ◽  
Large Eddy Simulation ◽  
Laser Beam ◽  
Beam Propagation ◽  
Laser Beam Propagation ◽  
Jet Engine ◽  
Eddy Simulation ◽  
Large Eddy

The relation between losses and entry-flow conditions in short dump diffusers for combustors

1988 ◽  
Vol 92 (920) ◽  
pp. 390-396 ◽  
Author(s):  
A. Klein
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
Radial Direction ◽  
Flow Conditions ◽  
Compressor Blades ◽  
Inlet Flow ◽  
Jet Engine ◽  
Satisfactory Degree ◽  
Blockage Factor ◽  
Experimental Correlation

SummaryAn experimental correlation is presented between the losses and the inlet flow conditions in short dump diffusers for turbojet combustors. Cascades of compressor blades upstream of the diffuser were used to make the flow field at inlet similar to that in a real jet engine. The flow field was altered in two ways — by varying the distance between the cascades and the diffuser inlet plane and by changing the blade aspect ratio. The measurements show clearly that distortions in the radial direction affect the losses to a much larger extent than non-uniformities in the circumferential direction. In consequence, the performance can be correlated to a satisfactory degree of accuracy simply by using the radial blockage factor at inlet.

Interpretation of Gas Turbine Response Due to Dust Ingestion

1987 ◽  
Vol 109 (3) ◽  
pp. 344-352 ◽  
Author(s):  
P. F. Batcho ◽  
J. C. Moller ◽  
C. Padova ◽  
M. G. Dunn
Keyword(s):  
Secondary Flows ◽  
Tip Clearance ◽  
Advanced Technology ◽  
Compressor Blades ◽  
Engine Operation ◽  
Performance Deterioration ◽  
Particle Ingestion ◽  
Dust Ingestion ◽  
Increased Susceptibility ◽  
Good Agreement

A measurement program currently underway at Arvin/Calspan Advanced Technology Center has been used in the evaluation of observed engine behavior during dust ingestion. The Pratt and Whitney TF33 turbofan and J57 turbojet were used in the investigation. Solid particle ingestion was found to erode the compressor blades and result in substantial performance deterioration. The engines were found to have increased susceptibility to surge at low power settings. The roles that anti-ice and intercompressor bleed airplay in surge avoidance are discussed. A discussion of the fuel controller behavior in a deteriorated engine and its effect during steady-state engine operation is also presented. Experimental data obtained during testing were compared to a predictive capability developed to describe deteriorated engine response. The effects of tip clearance, blade profile, and secondary flows were taken into account. The results show good agreement with experimentally observed engine behavior.

scholarly journals Influence of Fouling on Compressor Dynamics: Experimental and Modeling Approach

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Gbanaibolou Jombo ◽  
Jiri Pecinka ◽  
Suresh Sampath ◽  
David Mba
Keyword(s):  
Flow Field ◽  
Pressure Rise ◽  
Flow Coefficient ◽  
Test Rig ◽  
Compressor Blades ◽  
Average Roughness ◽  
Jet Engine ◽  
Engine Model ◽  
And Performance ◽  
Field Disturbance

The effect of compressor fouling on the performance of a gas turbine has been the subject of several papers; however, the goal of this paper is to address a more fundamental question of the effect of fouling, which is the onset of unstable operation of the compressor. Compressor fouling experiments have been carried out on a test rig refitted with TJ100 small jet engine with centrifugal compressor. Fouling on the compressor blade was simulated with texturized paint with average roughness value of 6 μm. Compressor characteristic was measured for both the clean (baseline) and fouled compressor blades at several rotational speeds by throttling the engine with variable exhaust nozzle. A Greitzer-type compression system model has been applied based on the geometric and performance parameters of the TJ100 small jet engine test rig. Frequency of plenum pressure fluctuation, the mean disturbance flow coefficient, and pressure-rise coefficient at the onset of plenum flow field disturbance predicted by the model was compared with the measurement for both the baseline and fouled engine. Model prediction of the flow field parameters at inception of unstable operation in the compressor showed good agreement with the experimental data. The results proved that used simple Greitzer model is suitable for prediction of the engine compressor unstable behavior and prediction of the mild surge inception point for both the clean and the fouled compressor.

A Subdomain Method for the Aeroacoustic Simulation of a Generic Side View Mirror

2013 ◽  
Vol 437 ◽  
pp. 321-324
Author(s):  
Li Na Huang ◽  
Ming Xin Xue ◽  
Hao Dong ◽  
Bo Yang
Keyword(s):  
Flow Field ◽  
Aerodynamic Noise ◽  
Complex Geometries ◽  
Side View ◽  
Cell Numbers ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Subdomain Method ◽  
Aeroacoustic Simulation ◽  
Good Agreement

The aerodynamic noise caused by the flow field around a generic side view mirror (SVM) was simulated using a subdomain large eddy simulation (LES) method. In this method, the LES solution could be run only in the subdomain, which can be the flow field near the SVM. The subdomain LES results show good agreement with the cited experimental data in some related works. With the principal advantage of saving CFD cell numbers, the subdomain LES method would be a perspective way to simulate the aerodynamic noise of complex geometries such as the real automobiles.

Grid sensitivity of flow field and noise of high-Reynolds-number jets computed by large-eddy simulation

2018 ◽  
Vol 17 (4-5) ◽  
pp. 399-424 ◽  
Author(s):  
Christophe Bogey
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Flow Field ◽  
High Reynolds Number ◽  
Mean Velocity ◽  
Laminar Jet ◽  
Eddy Simulation ◽  
Large Eddy ◽  
High Reynolds ◽  
Jet Axis

Three isothermal round jets at a Mach number of 0.9 and a diameter-based Reynolds number of 105 are computed by large-eddy simulation using four different meshes in order to investigate the grid sensitivity of the jet flow field and noise. The jets correspond to two initially fully laminar jets and one initially strongly disturbed jet considered in previous numerical studies. At the exit of a pipe nozzle of radius r0, they exhibit laminar boundary-layer mean-velocity profiles of thickness [Formula: see text] and [Formula: see text], respectively. For the third jet, a peak turbulence intensity close to 9% is also imposed by forcing the boundary layer in the nozzle. The grids contain up to one billion points, and, compared to the grids used in previous simulations, they are finer in the axial direction downstream of the nozzle and in the radial direction on the jet axis and in the outer region of the mixing layers. The main flow field and noise characteristics given by the simulations, including the mixing-layer thickness, the centerline mean velocity, the turbulence intensities on the nozzle lip line and the jet axis, spectra of velocity and far-field pressure obtained from the jet near field by solving the isentropic linearized Euler equations, are presented. With respect to those from previous studies, the results are very similar for the initially laminar jet with thick boundary layers, but they differ significantly for the initially laminar jet with thin boundary layers and for the initially disturbed jet. For the latter two jets, using a finer grid leads to a faster flow development, to higher turbulence intensities in the shear layers and at the end of the potential core, to stronger large-scale structures, and to the generation of more low-frequency noise. Moreover, very small mesh spacings appear to be necessary all along the jet mixing layers, and in particular during their early stages of growth, to properly capture the formation and dynamics of the flow coherent structures and thus obtain results in good agreement with measurements available for high-Reynolds-number jets.

Modeling Wind Flow and Particulate Pollutant Dispersion Around a Realistic Model of a Building Using Large-Eddy Simulation

2012 ◽  
Author(s):  
Behtash Tavakoli ◽  
Goodarz Ahmadi
Keyword(s):  
Air Pollution ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Model Comparison ◽  
Urban Air Pollution ◽  
Urban Air ◽  
Wind Flow ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy

Urban air pollution has been of concern due to its adverse effect on human health. A major portion of urban air pollution is attributed to vehicle emissions. Center of Excellence (CoE) Building was built in Syracuse NY at the intersection of two major highways. The building is fully instrumented for assessing outdoor and indoor air pollutions. In this study the airflow and the dispersion of particulate air pollutants emitted from the highways surrounding the CoE building were analyzed. The wind flow around the model of the CoE building was first simulated using the RANS model. Comparison of the numerical simulations with the available PIV experimental data showed that the RANS turbulence model was not able to capture all features of the flow field due to the complexity of the building’s geometry. While the pressure field on the walls of the building model matched with those measured by the pressure taps, some aspects of the airflow velocity profile were not in agreement with the PIV data. The computational modeling of the wind flow around the building was then performed using the Large-Eddy Simulation (LES) approach. The mean velocity magnitude predicted by the LES showed good agreement with the experimental PIV measurements. The simulated flow field was used to predict the dispersion of the particulate pollutant around the building and the deposition fraction of particles on the walls of the building is studied.

scholarly journals Large-eddy simulation study of turbulent flow around a rectangular spur dike

2018 ◽  
Vol 40 ◽  
pp. 05013
Author(s):  
Seokkoo Kang
Keyword(s):  
Large Eddy Simulation ◽  
Three Dimensional ◽  
Recirculation Region ◽  
Three Dimensional Flow ◽  
Vortex System ◽  
Spur Dike ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Acoustic Doppler Velocimetry ◽  
Good Agreement

High-resolution large-eddy simulation (LES) is carried out for investigating three-dimensional flow fields around a rectangular spur dike installed in an open-channel flume. The LES showed good agreement with the measurement obtained using Acoustic Doppler Velocimetry. Analysis of the LES result shows that the flow structure around and in the wake of the spur dike is highly complex and three-dimensional. Namely, flow upstream of the spur dike is featured by a vortex system near the bed, another vortex system beneath the free surface, and a recirculation region in front of the spur dike. All of these flow structures are laterally oriented. Moreover, flow in the wake region consists of a large vertically oriented recirculation region and a smaller laterally oriented recirculation region near the bottom corner downstream of the spur dike.

LES Combustion Model With Stretch and Heat Loss Effects for Prediction of Premix Flame Characteristics and Dynamics

2017 ◽  
Author(s):  
Luis Tay-Wo-Chong ◽  
Alessandro Scarpato ◽  
Wolfgang Polifke
Keyword(s):  
Flow Field ◽  
Heat Loss ◽  
Turbulent Combustion ◽  
Flame Stabilization ◽  
Combustion Model ◽  
Swirl Burner ◽  
Combustion Models ◽  
Variable Approach ◽  
Large Eddy ◽  
Good Agreement

The present paper extends an approach to include effects of stretch and heat losses into turbulent combustion models from the RANS framework to the LES framework. This approach has shown the potential to improve the prediction of flame stabilization by considering these combined effects. The model is based on the calculation of the consumption speed of laminar premixed flames influenced by variations in strain and heat loss in asymmetric counterflow configurations. The consumption speed depending on strain and heat loss is introduced into a turbulent combustion model based on a progress variable approach. Large Eddy Simulations of a fully-premixed axial swirl burner with and without the influence of stretch and heat loss effects are carried out and validated against flow field and OH* chemiluminescence measurements for different power ratings and equivalence ratios. Flame dynamics are also investigated by extracting the Flame Transfer Function of the fully-premixed axial swirl burner with System Identification methods. Good agreement on the flow field, flame characteristics and dynamics between experiment and simulation was obtained with the inclusion of stretch and heat loss effects into the combustion model. Results show the importance of including these effects into turbulence combustion models for the design of premix burners for gas turbine combustors.

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