scholarly journals Analysis of Multi-Stream Fuel Injector Flow Using Zonal Proper Orthogonal Decomposition

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1789
Author(s):  
Daniel Butcher ◽  
Adrian Spencer
Keyword(s):  
Velocity Field ◽  
Proper Orthogonal Decomposition ◽  
Significant Proportion ◽  
Flow Region ◽  
Orthogonal Decomposition ◽  
Stereoscopic Particle Image Velocimetry ◽  
Fuel Injector ◽  
Velocity Data ◽  
Lean Burn ◽  
Proper Orthogonal

The 3-component velocity distribution of two lean-burn gas turbine fuel injectors are measured at a planar location near and parallel to the injector outlet. The two injectors are nominally the same design, but one features blocked central passages to study the effects of the presence of multi-streams and reveal the single stream characteristics embedded within the multi-stream configuration. Stereoscopic particle image velocimetry is used in an isothermal, non-reacting water analogue flow facility at an engine relevant Reynolds number. The velocity data is analysed using proper orthogonal decomposition (POD) and the work introduces the concept of Zonal POD. This is the splitting of the velocity field into zones prior to the calculation of POD modes to better identify prominent structures and features associated with each zone. Because modes are sorted by the area averaged energy contribution, zoning of a velocity field of interest may change the individual modes and will almost certainly change their order for anything other than trivial flow fields. Analysis of ensemble average and velocity fluctuation profiles reveals a radial shift outboard of the mains flow with the presence of the pilot as well as a general increase in RMS across the intermediate region between the pilot and mains flows. Analysis of POD temporal coefficients in the frequency domain reveals a low-frequency peak is evident in the mains flow region, but which may be affected by the presence of pilot flow. Furthermore, application of the ZPOD technique results in a closer representation of the velocity data for a given number of modes. This shows the behaviour of the unsteady pilot flow and reveals that a significant proportion of the fluctuating energy, RMS, is caused by this characteristic.

Analysis of Particle Image Velocimetry Measurements of Natural Convection in an Enclosure Using Proper Orthogonal Decomposition

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Nirmalendu Biswas ◽  
Souvick Chatterjee ◽  
Mithun Das ◽  
Amlan Garai ◽  
Prokash C. Roy ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Natural Convection ◽  
Velocity Field ◽  
Proper Orthogonal Decomposition ◽  
Particle Image ◽  
Field Measurements ◽  
Orthogonal Decomposition ◽  
Image Velocimetry ◽  
Low Dimensional ◽  
Proper Orthogonal

This work investigates natural convection in an enclosure with localized heating on the bottom wall with a flushed or protruded heat source and cooled on the top and the side walls. Velocity field measurements are done by using 2D particle image velocimetry (PIV) technique. Proper orthogonal decomposition (POD) has been used to create low dimensional approximations of the system for predicting the flow structures. The POD-based analysis reveals the modal structure of the flow field and also allows reconstruction of velocity field at conditions other than those used in PIV study.

scholarly journals On the Application of Proper Orthogonal Decomposition (POD) for In-Cylinder Flow Analysis

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2261 ◽  
Author(s):  
Mohammed El-Adawy ◽  
Morgan Heikal ◽  
A. A. Aziz ◽  
Ibrahim Adam ◽  
Mhadi Ismael ◽  
...  
Keyword(s):  
Physical Properties ◽  
Proper Orthogonal Decomposition ◽  
Pressure Difference ◽  
Velocity Vector ◽  
Vector Fields ◽  
Orthogonal Decomposition ◽  
Stereoscopic Particle Image Velocimetry ◽  
Pod Analysis ◽  
Cylinder Flow ◽  
Proper Orthogonal

Proper orthogonal decomposition (POD) is a coherent structure identification technique based on either measured or computed data sets. Recently, POD has been adopted for the analysis of the in-cylinder flows inside internal combustion engines. In this study, stereoscopic particle image velocimetry (Stereo-PIV) measurements were carried out at the central vertical tumble plane inside an engine cylinder to acquire the velocity vector fields for the in-cylinder flow under different experimental conditions. Afterwards, the POD analysis were performed firstly on synthetic velocity vector fields with known characteristics in order to extract some fundamental properties of the POD technique. These data were used to reveal how the physical properties of coherent structures were captured and distributed among the POD modes, in addition to illustrate the difference between subtracting and non-subtracting the ensemble average prior to conducting POD on datasets. Moreover, two case studies for the in-cylinder flow at different valve lifts and different pressure differences across the air intake valves were presented and discussed as the effect of both valve lifts and pressure difference have not been investigated before using phase-invariant POD analysis. The results demonstrated that for repeatable flow pattern, only the first mode was sufficient to reconstruct the physical properties of the flow. Furthermore, POD analysis confirmed the negligible effect of pressure difference and subsequently the effect of engine speed on flow structures.

Particle Image Velocimetry and Proper Orthogonal Decomposition Applied to Aerodynamic Sound Source Region Visualization in Organ Flue Pipe

2015 ◽  
Vol 40 (4) ◽  
pp. 475-484 ◽  
Author(s):  
Witold Mickiewicz
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Proper Orthogonal Decomposition ◽  
Particle Image ◽  
Orthogonal Decomposition ◽  
Sound Generation ◽  
Image Velocimetry ◽  
The Mean ◽  
Temporal Modes ◽  
Proper Orthogonal

AbstractThe paper presents experimental results of the visualization of the nonlinear aeroacoustic sound generation phenomena occurring in organ flue pipe. The phase-locked particle image velocimetry technique is applied to visualize the mixed velocity field in the transparent organ flue pipe model made from Plexiglas. Presented measurements were done using synchronization to the tone generated by the pipe itself sup- plied by controlled air flow with seeding particles. The time series of raw velocity field distribution images show nonlinear sound generation mechanisms: the large amplitude of deflection of the mean flue jet and vortex shedding in the region of pipe mouth. Proper Orthogonal Decomposition (POD) was then applied to the experimental data to separately visualize the mean mass flow, pulsating jet mass flow with vortices and also sound waves near the generation region as well as inside and outside of the pipe. The resulting POD spatial and temporal modes were used to approximate the acoustic velocity field behaviour at the pipe fundamental frequency. The temporal modes shapes are in a good agreement with the microphone pressure signal shape registered from a distance. Obtained decomposed spatial modes give interesting insight into sound generating region of the organ pipe and the transition area towards the pure acoustic field inside the resonance pipe. They can give qualitative and quantitative data to verify existing sound generation models used in Computational Fluid Dynamics (CFD) and Computational Aero-Acoustics (CAA).

Proper Orthogonal Decomposition Analysis of Non-Swirling Turbulent Stratified and Premixed Methane/Air Flames

2014 ◽  
Author(s):  
M. Mustafa Kamal ◽  
Christophe Duwig ◽  
Saravanan Balusamy ◽  
Ruigang Zhou ◽  
Simone Hochgreb
Keyword(s):  
Flow Field ◽  
Proper Orthogonal Decomposition ◽  
High Speed ◽  
Large Scale ◽  
Bluff Body ◽  
Decomposition Analysis ◽  
Orthogonal Decomposition ◽  
Stereoscopic Particle Image Velocimetry ◽  
Large Scale Flow ◽  
Proper Orthogonal

This paper reports proper orthogonal decomposition (POD) analyses for the velocity fields measured in a test burner. The Cambridge/Sandia Stratified Swirl Burner has been used in various studies as a benchmark for high resolution scalar and velocity measurements, for comparison with numerical model prediction. Flow field data was collected for a series of bluff-body stabilized premixed and stratified methane/air flames at turbulent, globally lean conditions (ϕ = 0.75) using high speed stereoscopic particle image velocimetry (HS-SPIV). In this paper, a modal analysis was performed to identify the large scale flow structures and their impact on the flame dynamics. The high speed PIV system was operated at 3 kHz to acquire a series of 4096 sequential flow field images both for reactive and non-reactive cases, sufficient to follow the large-scale spatial and temporal evolution of flame and flow dynamics. The POD analysis allows identification of vortical structures, created by the bluff body, and in the shear layers surrounding the stabilization point. In addition, the analysis reveals that dominant structures are a strong function of the mixture stratification in the flow field. The dominant energetic modes of reactive and non-reactive flows are very different, as the expansion of gases and the high temperatures alter the unstable modes and their survival in the flow.

Stereoscopic Particle Image Velocimetry Measurements and Proper Orthogonal Decomposition Analysis of the In-Cylinder Flow of Gasoline Direct Injection Engine

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Mohammed El-Adawy ◽  
M. R. Heikal ◽  
A. Rashid A. Aziz
Keyword(s):  
Particle Image Velocimetry ◽  
Proper Orthogonal Decomposition ◽  
Particle Image ◽  
Direct Injection ◽  
Orthogonal Decomposition ◽  
Stereoscopic Particle Image Velocimetry ◽  
Gasoline Direct Injection ◽  
Image Velocimetry ◽  
Gdi Engine ◽  
Proper Orthogonal

Intake generated flows are known to have a fundamental influence on the combustion both in spark ignition (SI) and compression ignition engines. This study experimentally investigated the tumble flow structures inside a cylinder of gasoline direct injection (GDI) engine utilizing a stereoscopic time-resolved particle image velocimetry (PIV). The experiments were conducted in a GDI engine head for a number of fixed valve lifts and 150 mmH2O pressure difference across the intake valves. A tumble flow analysis was carried out considering different vertical tumble planes. In addition, the proper orthogonal decomposition (POD) identification technique was applied on the PIV data in order to spatially analyze the structures embedded in the instantaneous velocity data sets. The results showed that the flow was dominated by a strong tumble motion in the middle of cylinder at high valve lifts (8–10 mm). Moreover, it is worth pointing out that, because of the complexity of the flow at the high valve lifts, the flow energy was distributed over a higher number of POD modes. This was confirmed by the need of a higher number of POD modes needed to reconstruct the original velocity field to the same level of fidelity.

A Numerical Study on the Effects of Acoustic Forcing on Fuel Spray Dynamics in Gas Turbines

2020 ◽  
Author(s):  
Nicholas C. W. Treleaven ◽  
Andrew Garmory ◽  
Gary J. Page
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Gas Turbines ◽  
Numerical Study ◽  
Mixture Fraction ◽  
Orthogonal Decomposition ◽  
Computational Domain ◽  
Fuel Injector ◽  
Design Modification ◽  
Acoustic Forcing ◽  
Proper Orthogonal

Abstract In the case of aircraft engines, the fuel is injected as a liquid spray which may play a role in thermoacoustic instabilities through creating changes to the mixture fraction inside the combustion chamber. This study uses two-phase incompressible non-reacting large eddy simulation with Lagrangian particle tracking to show how spray droplets of different sizes can be affected by large scale hydrodynamic structures and acoustic forcing. The forcing is applied at the inlets of a truncated computational domain that only includes the geometry downstream of the fuel injector using the newly developed PODFS (proper orthogonal decomposition Fourier series) method. The PODFS is a model that can reproduce the effects of acoustic forcing by extracting planes of data from an auxiliary acoustically forced compressible unsteady Reynolds averaged Navier-Stokes simulation. A proper orthogonal decomposition analysis shows that fuel droplets of a typical size seen in jet engines are more sensitive to acoustic and hydrodynamic structures than droplets with an order of magnitude larger or smaller diameter, consistent with their Stokes number. Phase and azimuthally averaged results show that fluctuations of the spray mixture fraction represented by large droplets affect the total spray mixture fraction much more than fluctuations of the small droplets. An additional intermittent spray dispersion mechanism was identified that is due to intermittent vorticity being generated between the two outer injector flow passages. An injector design modification has been suggested that will reduce the prevalence of this mechanism.

scholarly journals A turbulent jet in crossflow analysed with proper orthogonal decomposition

2007 ◽  
Vol 583 ◽  
pp. 199-227 ◽  
Author(s):  
KNUD ERIK MEYER ◽  
JAKOB M. PEDERSEN ◽  
OKTAY ÖZCAN
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Shear Layer ◽  
Vortex Pair ◽  
Orthogonal Decomposition ◽  
Turbulent Pipe Flow ◽  
Stereoscopic Particle Image Velocimetry ◽  
Wake Vortices ◽  
Jet In Crossflow ◽  
Crossflow Velocity ◽  
Proper Orthogonal

Detailed instantaneous velocity fields of a jet in crossflow have been measured with stereoscopic particle image velocimetry (PIV). The jet originated from a fully developed turbulent pipe flow and entered a crossflow with a turbulent boundary layer. The Reynolds number based on crossflow velocity and pipe diameter was 2400 and the jet to crossflow velocity ratios wereR=3.3 andR=1.3. The experimental data have been analysed by proper orthogonal decomposition (POD). ForR=3.3, the results in several different planes indicate that the wake vortices are the dominant dynamic flow structures and that they interact strongly with the jet core. The analysis identifies jet shear-layer vortices and finds that these vortical structures are more local and thus less dominant. ForR=1.3, on the other hand, jet shear-layer vortices are the most dominant, while the wake vortices are much less important. For both cases, the analysis finds that the shear-layer vortices are not coupled to the dynamics of the wake vortices. Finally, the hanging vortices are identified and their contribution to the counter-rotating vortex pair (CVP) and interaction with the newly created wake vortices are described.

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