Numerical Analysis of SDBD-Plasma Based Separation Control on the Blades of a Rotating Impeller

2016 ◽  
Author(s):  
Shawn Aram ◽  
Yu-Tai Lee ◽  
Hua Shan
Keyword(s):  
Applied Voltage ◽  
Body Force ◽  
Numerical Study ◽  
Pulse Amplitude ◽  
Boundary Layer Separation ◽  
Numerical Approach ◽  
Computational Method ◽  
Force Model ◽  
Centrifugal Fan ◽  
Ionized Air

A numerical study is conducted to explore the performance and efficiency of Single Dielectric Barrier Discharge (SDBD) plasma actuators for controlling the turbulent boundary layer separation that occurs on the blades of a centrifugal fan. The numerical approach is based on the computational method developed previously to couple a DBD Electro Hydro-Dynamic (EHD) body force model with a RANS/LES flow model. The EHD body force model is based on solving the electrostatic equations for the electric potential due to applied voltage and the net charge density due to ionized air. The efficiency of the actuator at four different alternative current (AC) waveforms including sine, pulse, square, and pulse-amplitude-modulated sine is investigated in this study. The effect of applied voltage on the performance of the plasma actuator is also examined for all waveforms.

Application of an Integrated Flow and DBD Plasma Actuation Model to a High-Lift Airfoil: Part II — LES

2015 ◽  
Author(s):  
Shawn Aram ◽  
Hua Shan ◽  
Yu-Tai Lee
Keyword(s):  
Electric Potential ◽  
Body Force ◽  
Numerical Study ◽  
Pulse Amplitude ◽  
Boundary Layer Separation ◽  
Critical Voltage ◽  
Force Model ◽  
Dbd Plasma ◽  
Experimental Conditions ◽  
High Lift

A numerical study is conducted to explore the effect of a single dielectric barrier discharge (SDBD) plasma actuator for controlling a turbulent boundary layer separation on a deflected flap of a high-lift airfoil at a chord-based Reynolds number of 240000. An integrated numerical model consisting of a DBD electro-hydrodynamic (EHD) body force model and computational fluid dynamics (CFD) package called NavyFoam is employed in this study. The EHD body force is calculated by solving the Partial Deferential Equation (PDE)-based electrostatic equations for electric potential due to applied voltage and net charged density due to ionized air. The electric potential equation, the net charge density equation, and the flow equations are solved in separate computational domains. Comparison of current computational results against experimental data indicates reasonable agreement between the two studies for the baseline flow as well as controlled cases using two AC waveforms including sine and pulse-amplitude-modulated sine with different modulation frequencies. Performance of the actuator is also examined for the square and pulse AC waveforms. It is found that at the experimental conditions, the pulse-amplitude-modulated sine waveform provides the most lift enhancement in comparison with other waveforms used in this study, despite the least power input that it requires to operate. The effect of the input voltage amplitude on the performance of the actuator is also examined for the sine and pulse-amplitude-modulated sine waveforms. It is shown that beyond a critical voltage, the sine wave is more effective in improving the aerodynamic performance of the airfoil than the other waveform.

Numerical Modeling of Dielectric Barrier Discharge Plasma Actuation

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Hua Shan ◽  
Yu-Tai Lee
Keyword(s):  
Charge Density ◽  
Dielectric Barrier Discharge ◽  
Body Force ◽  
Incompressible Flows ◽  
Barrier Discharge ◽  
Computational Method ◽  
Force Model ◽  
Dbd Plasma ◽  
Net Charge ◽  
Dielectric Barrier

A computational method has been developed to couple the electrohydrodynamic (EHD) body forces induced by dielectric barrier discharge (DBD) actuation with unsteady Reynolds-Averaged Navier–Stokes (URANS) model or large eddy simulation (LES) for incompressible flows. The EHD body force model is based on solving the electrostatic equations for electric potential and net charge density. The boundary condition for net charge density on the dielectric surface is obtained from a space–time lumped-element (STLE) circuit model or an empirical model. The DBD–URANS/LES coupled solver has been implemented using a multiple-domain approach and a multiple subcycle technique. The DBD plasma-induced flow in a quiescent environment is used to validate the coupled solver, evaluate different EHD body force models, and compare the performance of the actuator driven by voltage with various waveforms and amplitudes.

PARALLEL SOLVER FOR THE SIMULATIONS OF DETONATION WAVES ON UNSTRUCTURED GRIDS

2020 ◽  
Author(s):  
A. I. Lopato ◽  
◽  
A. G. Eremenko ◽  
Keyword(s):  
Chemical Kinetics ◽  
Numerical Scheme ◽  
Unstructured Grids ◽  
Numerical Study ◽  
Numerical Approach ◽  
Detonation Waves ◽  
Detailed Chemical Kinetics ◽  
Parallel Solver ◽  
Further Development ◽  
Detailed Chemical

Recently, we developed a numerical approach for the simulation of detonation waves on fully unstructured grids and applied it to the numerical study of the mechanisms of detonation initiation in multifocusing systems. Current work is devoted to further development of our numerical approach, namely, parallelization of the numerical scheme and introduction of more comprehensive detailed chemical kinetics scheme.

Numerical investigations on the effect of volute casing treatment for performance augmentation in a centrifugal fan

2021 ◽  
pp. 095440622110341
Author(s):  
Manjunath L Nilugal ◽  
K Vasudeva Karanth ◽  
Madhwesh N
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Casing Treatment ◽  
Sliding Mesh ◽  
Optimum Configuration

This article presents the effect of volute chamfering on the performance of a forward swept centrifugal fan. The numerical analysis is performed to obtain the performance parameters such as static pressure rise coefficient and total pressure coefficient for various flow coefficients. The chamfer ratio for the volute is optimized parametrically by providing a chamfer on either side of the volute. The influence of the chamfer ratio on the three dimensional flow domain was investigated numerically. The simulation is carried out using Re-Normalisation Group (RNG) k-[Formula: see text] turbulence model. The transient simulation of the fan system is done using standard sliding mesh method available in Fluent. It is found from the analysis that, configuration with chamfer ratio of 4.4 is found be the optimum configuration in terms of better performance characteristics. On an average, this optimum configuration provides improvement of about 6.3% in static pressure rise coefficient when compared to the base model. This optimized chamfer configuration also gives a higher total pressure coefficient of about 3% validating the augmentation in static pressure rise coefficient with respect to the base model. Hence, this numerical study establishes the effectiveness of optimally providing volute chamfer on the overall performance improvement of forward bladed centrifugal fan.

scholarly journals Computational Modeling of Vortex Generators for Turbomachinery

2002 ◽  
Author(s):  
R. V. Chima
Keyword(s):  
Computational Models ◽  
Body Force ◽  
Secondary Flows ◽  
The Body ◽  
Vortex Generators ◽  
Force Model ◽  
Suction Surface ◽  
Near Surface ◽  
Compressor Rotor ◽  
Surface Particle

In this work computational models were developed and used to investigate applications of vortex generators (VGs) to turbomachinery. The work was aimed at increasing the efficiency of compressor components designed for the NASA Ultra Efficient Engine Technology (UEET) program. Initial calculations were used to investigate the physical behavior of VGs. A parametric study of the effects of VG height was done using 3-D calculations of isolated VGs. A body force model was developed to simulate the effects of VGs without requiring complicated grids. The model was calibrated using 2-D calculations of the VG vanes and was validated using the 3-D results. Then three applications of VGs to a compressor rotor and stator were investigated: 1. The results of the 3-D calculations were used to simulate the use of small casing VGs used to generate rotor preswirl or counterswirl. Computed performance maps were used to evaluate the effects of VGs. 2. The body force model was used to simulate large partspan splitters on the casing ahead of the stator. Computed loss buckets showed the effects of the VGs. 3. The body force model was also used to investigate the use of tiny VGs on the stator suction surface for controlling secondary flows. Near-surface particle traces and exit loss profiles were used to evaluate the effects of the VGs.

Three body force model for lattice dynamics of copper

1986 ◽  
Vol 57 (8) ◽  
pp. 559-562 ◽  
Author(s):  
H. Nait-Laziz ◽  
K.K. Chopra
Keyword(s):  
Lattice Dynamics ◽  
Body Force ◽  
Force Model ◽  
Three Body

scholarly journals A Numerically Supported Investigation of the 3D Flow in Centrifugal Impellers: Part I — The Validation Base

1996 ◽  
Author(s):  
Ch. Hirsch ◽  
S. Kang ◽  
G. Pointel
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Boundary Layer Separation ◽  
Numerical Approach ◽  
Secondary Flows ◽  
Pump Impeller ◽  
High Loss ◽  
Leakage Flows ◽  
Fine Mesh ◽  
Radial Pump

The three-dimensional flow in centrifugal impellers is investigated on the basis of a detailed analysis of the results of numerical simulations. In order to gain confidence in this process, an in-depth validation is performed, based on computations of Krain’s centrifugal compressor and of a radial pump impeller, both with vaneless diffusers. Detailed comparisons with available experimental data provide high confidence in the numerical tools and results. The appearance of a high loss ‘wake’ region results from the transport of boundary layer material from the blade surfaces to the shroud region and its location depends on the balance between secondary and tip leakage flows and is not necessarily connected to 3D boundary layer separation. Although the low momentum spots near the shroud can interfere with 3D separated regions, the main outcome of the present analysis is that these are two distinct phenomena. Part I of this paper focuses on the validation base of the numerical approach, based on fine mesh simulations, while Part II presents an analysis of the different contributions to the secondary flows and attempts to estimate their effect on the overall flow pattern.

scholarly journals Numerical Study of Centrifugal Fan with Slots in Blade Surface

2015 ◽  
Vol 126 ◽  
pp. 588-591 ◽  
Author(s):  
Rui Rong ◽  
Ke Cui ◽  
Zijun Li ◽  
Zhengren Wu
Keyword(s):  
Numerical Study ◽  
Centrifugal Fan ◽  
Blade Surface

Comparison of Inviscid Computations With Theory and Experiment in Vibrating Transonic Compressor Cascades

1990 ◽  
Author(s):  
G. A. Gerolymos ◽  
E. Blin ◽  
H. Quiniou
Keyword(s):  
Boundary Layer ◽  
Plate Theory ◽  
Strong Shock ◽  
Acoustic Resonance ◽  
Boundary Layer Separation ◽  
Computational Method ◽  
Viscous Effects ◽  
Transonic Compressor ◽  
Boundary Layer Interaction ◽  
Interaction Regions

The prediction of unsteady flow in vibrating transonic cascades is essential in assessing the aeroelastic stability of fans and compressors. In the present work an existing computational code, based on the numerical integration of the unsteady Euler equations, in blade-to-blade surface formulation, is validated by comparison with available theoretical and experimental results. Comparison with the flat plate theory of Verdon is, globally, satisfactory. Nevertheless, the computational results do not exhibit any particular behaviour at acoustic resonance. The use of a 1-D nonreflecting boundary condition does not significantly alter the results. Comparison of the computational method with experimental data from started and unstarted supersonic flows, with strong shock waves, reveals that, notwithstanding the globally satisfactory performance of the method, viscous effects are prominent at the shock wave/boundary layer interaction regions, where boundary layer separation introduces a pressure harmonic phase shift, which is not presicted by inviscid methods.

Sloshing in Rectangular and Cylindrical Tanks

2002 ◽  
Vol 46 (03) ◽  
pp. 186-200 ◽  
Author(s):  
Pierre C. Sames ◽  
Delphine Marcouly ◽  
Thomas E. Schellin
Keyword(s):  
Free Surface ◽  
Finite Volume ◽  
Temporal Evolution ◽  
Numerical Study ◽  
Computational Method ◽  
Test Cases ◽  
Grid Refinement ◽  
Cylindrical Tank ◽  
Excitation Period ◽  
Cylindrical Tanks

To validate an existing finite volume computational method, featuring a novel scheme to capture the temporal evolution of the free surface, fluid motions in partially filled tanks were simulated. The purpose was to compare computational and experimental results for test cases where measurements were available. Investigations comprised sloshing in a rectangular tank with a baffle at 60% filling level and in a cylindrical tank at 50% filling level. The numerical study started with examining effects of systematic grid refinement and concluded with examining effects of three-dimensionality and effects of variation of excitation period and amplitude. Predicted time traces of pressures and forces compared favorably with measurements.

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