cven 679 term project presentation multiphase flow studies using piv collaborators: champa joshi...
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CVEN 679 Term Project Presentation
Multiphase Flow studies using Multiphase Flow studies using PIVPIV
Collaborators:Collaborators:
CHAMPA JOSHICHAMPA JOSHI
TIRTHARAJ BHAUMIKTIRTHARAJ BHAUMIK
RAMAKRISHNAN HARI RAMAKRISHNAN HARI PRASADPRASAD
PROJECT OBJECTIVEPROJECT OBJECTIVE
The PIV (Particle Image Velocimetry) The PIV (Particle Image Velocimetry) measurement method is used to obtain relevant measurement method is used to obtain relevant parameters in the study of multiphase plumes parameters in the study of multiphase plumes with the objective of validating numerical models with the objective of validating numerical models and use them to predict field phenomena.and use them to predict field phenomena.
MULTIPHASE FLOW BASICSMULTIPHASE FLOW BASICS
Multiphase flows are fluid flows involving Multiphase flows are fluid flows involving the dynamics of more than one phase or the dynamics of more than one phase or constituentconstituent
One of the core areas of research inOne of the core areas of research in Environmental Fluid MechanicsEnvironmental Fluid Mechanics
Dispersed & Continuous PhasesDispersed & Continuous PhasesDispersed Phase : Bubbles, Droplets, PowderDispersed Phase : Bubbles, Droplets, Powder
Continuous Phase : Water, AirContinuous Phase : Water, Air Jets:Jets:
Driving force – Momentum flux of dispersed phaseDriving force – Momentum flux of dispersed phase Plumes:Plumes:
Driving force – Buoyancy flux of dispersed phase Driving force – Buoyancy flux of dispersed phase
ApplicationsApplications
Bubble BreakwatersBubble Breakwaters Antifreeze measures in HarborsAntifreeze measures in Harbors Bubble curtains for Oil spill Bubble curtains for Oil spill
containmentcontainment COCO22 Sequestration in Ocean Sequestration in Ocean Lake AerationLake Aeration Reservoir DestratificationReservoir Destratification
SCHEMATIC OF A SIMPLE AIR-BUBBLE PLUMESCHEMATIC OF A SIMPLE AIR-BUBBLE PLUME
BubblesBubbles (Dispersed Phase)
Water (Continuous phase)
MULTIPHASE PLUMES IN STRATIFIED MULTIPHASE PLUMES IN STRATIFIED ENVIRONMENTENVIRONMENT
LIF Image of a Type 3 plume
N=((-g/ρr)*(dρa/dz))1/2
hP
Dimensional Analysis:Dimensional Analysis:
hT = f (Qinit , Minit , Bb_init , Bw_init , us , N , HT )
0 0 0
Total no. of variables = 4Total no. of dimensions = 2 (L, T)
BUCKINGHAM-PI THEOREM
(4 – 2) = 2 non-dimensional groups
∏1 : Non-dimensional Trap Height
∏2 : Non-dimensional Bubble Slip Velocity
∏1 = hT / (B/N3)¼
∏2 = us / (BN)¼
∏1 = g ( ∏2 )
Single-phase plumes: ∏1 = 2.8
Two-phase plumes:
Relationship between the non-dimensional parameters validated from experiments:
∏1 = 2.8 – 0.27∏2 ∏1 = 5.2exp(-(П2 – 1.8)2/10.1)
Field Scale Complications:Field Scale Complications: Stratification profile may be non-linear Stratification profile may be non-linear
- N varies with depth- N varies with depth There may be bubble expansion There may be bubble expansion
- u- uss varies with depth varies with depth There may be more than one dispersed There may be more than one dispersed
phases presentphases present
LEADS TO:LEADS TO:
Poor correlation between lab and field scales!Poor correlation between lab and field scales!
REMEDY:REMEDY:Numerical models with parameters validated from laboratory Numerical models with parameters validated from laboratory
experiments can include the field-scale complicationsexperiments can include the field-scale complications
Governing Differential Equations:Governing Differential Equations:
Conservation of Mass fluxConservation of Mass flux Conservation of Momentum fluxConservation of Momentum flux Conservation of Buoyancy flux of dispersed phaseConservation of Buoyancy flux of dispersed phase Conservation of Buoyancy flux of continuous Conservation of Buoyancy flux of continuous
phasephase
Unknown parameters to be solved:Unknown parameters to be solved:
UUmm –– velocityvelocity of continuous phase of continuous phase 2b2b – – widthwidth of plume of plumeCCmm – – void fractionvoid fraction of dispersed phase of dispersed phaseg’g’ – – reduced gravityreduced gravity of continuous phase of continuous phase
Gaussian and Top-Hat profiles:Gaussian and Top-Hat profiles:
Top-Hat Distribution Gaussian Distribution
SELF – SIMILARITY ASSUMPTION
X(r,z) = X(z), -b r b
= 0 elsewhere
2
m 2 2
rX(r,z) = X (z)exp(- ), -b r b
b = 0 elsewhere
X: state variable of interest ( u, C, ∆ρ)
Derivation of the Governing Equations:Derivation of the Governing Equations:
Entrainment Hypothesis
Dilute plume assumption
Density locally invariant inside C.V
Balance of buoyant forces on two phases
Viscous Drag is negligible for water
Momentum of air bubbles is negligible
b b2
-b -b
b
-b
Q(z)= u(r,z)dA, M(z)= u (r,z)dA,
B(z) = g'(r,z) udA, dA = 2πrdr
2b
Numerical models:Numerical models:
Mixed-fluid model :Mixed-fluid model : McDougall (1978), McDougall (1978), Asaeda & Imberger Asaeda & Imberger
(1993)(1993)
- - Treats the dispersed and continuous phases as a single Treats the dispersed and continuous phases as a single mixturemixture
Two-fluid model : Two-fluid model : Socolofsky & Adams Socolofsky & Adams (2001)(2001)
- - Treats the dispersed and continuous phases as separate Treats the dispersed and continuous phases as separate entitiesentities
Numerical Model Equations:Numerical Model Equations:
NUMERICAL SCHEME USED: 4TH ORDER RUNGE-KUTTA
Critical Model Issues:Critical Model Issues:
Entrainment CoefficientEntrainment Coefficient
Initial conditionsInitial conditions
Um , b and alpha are to be estimated using PIV measurements
Particle Image VelocimetryParticle Image Velocimetry
Facilities & EquipmentsFacilities & Equipments
Experimental Tank Experimental Tank (40 x 40 x 70 cm)(40 x 40 x 70 cm) made of transparent acrylic glass (Plexiglas) made of transparent acrylic glass (Plexiglas) Diffuser source Diffuser source (Airstone - 1.4 cm dia) – produces bubbles of 3 mm dia above Q = (Airstone - 1.4 cm dia) – produces bubbles of 3 mm dia above Q =
0.25 l/min0.25 l/min Electronic Mass Flowmeter Electronic Mass Flowmeter (Aalborg GFM 171)(Aalborg GFM 171) and Needle valve and Needle valve 3.2 mm piping3.2 mm piping Laser Light Source: Laser Light Source: (Nd:YAG pulse laser)(Nd:YAG pulse laser)
-- Maximum powerMaximum power (400 mJ/pulse)(400 mJ/pulse)-- WavelengthWavelength (532 nm - green) (532 nm - green)-- Pulse widthPulse width ( 8 nanoseconds) ( 8 nanoseconds)-- Time interval between pulsesTime interval between pulses ( 4 ms ) ( 4 ms )-- Thickness of laser light sheetThickness of laser light sheet (4 mm) (4 mm)
OpticsOptics - Cylindrical Lens – creates planar light sheet - Cylindrical Lens – creates planar light sheet Seeding Particles Seeding Particles – Polyamide spheres (white, 50 – Polyamide spheres (white, 50 μμm diameter)m diameter) Camera (CCD) – Camera (CCD) – Flowmaster 3S (3)Flowmaster 3S (3)
-- Frame rateFrame rate (8 fps) (8 fps)-- PixelPixel ResolutionResolution (1280 x 1024) (1280 x 1024)-- Grayscale ResolutionGrayscale Resolution (12-bit : 0 to 4095 grayscales) (12-bit : 0 to 4095 grayscales)-- Field of ViewField of View (18cm x 18 cm for each of the 3 cameras) (18cm x 18 cm for each of the 3 cameras)-- Controllable exposure timeControllable exposure time (0.2 to 125 ms) (0.2 to 125 ms)
ComputerComputer-- Data analysis softwareData analysis software – DaVis (product of LaVision GmBH) – DaVis (product of LaVision GmBH)-- Synchronization unitSynchronization unit – controls timing of laser pulse triggering and camera – controls timing of laser pulse triggering and camera exposureexposure-- Frame Grabber Frame Grabber – captures frames and transfers to computer RAM and then – captures frames and transfers to computer RAM and then to Hard Diskto Hard Disk-- UtilitiesUtilities – Matlab – Matlab
PIV EPIV EXPERIMENTALXPERIMENTAL S SETUPETUP
MMEDIAN EDIAN FFILTERING FOR ILTERING FOR PIV PIV DATADATA
UMEDIAN – 1.5URMS < U < UMEDIAN + 1.5URMS
Interrogation Window – 16 X 16 pixels, 50% overlap
PTV APTV ANALYSIS BY NALYSIS BY TTHRESHOLDHRESHOLD
Original image
[mm]0 5 10 15 20 25 30 35 40 45 50
0
5
1015
20
2530
3540
45
50
Threshold applied image
[mm]0 5 10 15 20 25 30 35 40 45 50
0
510
15
2025
30
35
4045
50
Grayscale intensity Threshold Range for a 12-bit CCD camera: 0 – 4095
Intensity Threshold for the brighter bubbles: 2500
FFLUID & LUID & BBUBBLE UBBLE VVELOCITYELOCITY P PROFILESROFILES
Fluid velocity profile: Resembles Gaussian
Bubble velocity profile: Resembles Top-Hat
EENTRAINMENT NTRAINMENT CCOEFFICIENT FROM PIVOEFFICIENT FROM PIV
IMPORTANT FINDING: Alpha is not constant and varies non-linearly with depth
1( *) 0.055
2502( *)z
z
COMPARISON W/TWO-FLUID MODELCOMPARISON W/TWO-FLUID MODEL
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
0.01
0.02
0.03
0.04
0.05
z/H
T
Q/(Bz5)1/31.6 1.8 2 2.2 2.4 2.6 2.8 30
0.01
0.02
0.03
0.04
0.05
z/H
T
Um/(B/z)1/3
0.1 0.12 0.14 0.16 0.18 0.2 0.22 0.24 0.260
0.01
0.02
0.03
0.04
0.05
z/H
T
b/z0.2 0.3 0.4 0.5 0.6 0.70
0.01
0.02
0.03
0.04
0.05
z/H
T
M/(Bz2)2/3
Two-fluid Q0 = 1.5 l/min
Two-fluid Q0 = 1.0 l/min
Two-fluid Q0 = 0.5 l/min
Experimental
Model and experimental results agree appreciably well
COMPARISON W/MIXED-FLUID MODELCOMPARISON W/MIXED-FLUID MODEL
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
0.01
0.02
0.03
0.04
0.05
z/H
T
Q/(Bz5)1/31.5 2 2.5 3 3.5 4 4.5 50
0.01
0.02
0.03
0.04
0.05
z/H
T
Um
/(B/z)1/3
0.05 0.1 0.15 0.2 0.25 0.30
0.01
0.02
0.03
0.04
0.05
z/H
T
b/z0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90
0.01
0.02
0.03
0.04
0.05
z/H
T
M/(Bz2)2/3
Mixed-fluid Q0 = 1.5 l/min
Mixed-fluid Q0 = 1.0 l/min
Mixed-fluid Q0 = 0.5 l/min
Experimental
Model overpredicts the velocity of continuous phase and the momentum flux
RESULTS:RESULTS: PIV of unstratified bubble plume successfulPIV of unstratified bubble plume successful
Entrainment coefficient depends on bubble concentrationEntrainment coefficient depends on bubble concentration
Two-fluid models appear to match plume physics better than mixed fluid modelsTwo-fluid models appear to match plume physics better than mixed fluid models
ONGOING WORK:ONGOING WORK:
Combining three different FOV to get better aligned dataCombining three different FOV to get better aligned data
Application of PIV to stratified bubble plumeApplication of PIV to stratified bubble plume
Extending single plume numerical model to double plumeExtending single plume numerical model to double plume
Obtaining appropriate initial conditionsObtaining appropriate initial conditions
FUTURE SCOPE OF WORK:FUTURE SCOPE OF WORK: PIV-LIF Combined study for the bubble plumePIV-LIF Combined study for the bubble plume
Develop LES (Large Eddy Simulation) numerical models Develop LES (Large Eddy Simulation) numerical models
REAL-LIFE SCENARIOS:REAL-LIFE SCENARIOS: Ocean Ocean
Sequestration of Sequestration of Liquid COLiquid CO22 (constitutes (constitutes
64% of global greenhouse 64% of global greenhouse gas emissions)gas emissions)
Other Applications:Other Applications: Aeration of Lake/AquariumsAeration of Lake/Aquariums Fate of oil/chemicals released Fate of oil/chemicals released
in deep sea due to accidental in deep sea due to accidental leakages and blowoutsleakages and blowouts
Bio-medical EngineeringBio-medical Engineering- - blood flow modeling in a ventricular blood flow modeling in a ventricular assist deviceassist device
Chemical industriesChemical industries- - two-phase flow modeling due to two-phase flow modeling due to countercurrent chromatographycountercurrent chromatography
MetallurgyMetallurgy-- gas stirring of molten metals in ladles, gas stirring of molten metals in ladles, in nuclear devices and chemical in nuclear devices and chemical reactorsreactors
References:References:
Asaeda, T. & Imberger, J. (1993), ‘Structure of bubble plumes in linearly stratified environments’, Asaeda, T. & Imberger, J. (1993), ‘Structure of bubble plumes in linearly stratified environments’, J.Fluid Mech.J.Fluid Mech. 249,249, 35-57. 35-57.
Bergmann C. (2004), ‘Physical and Numerical studies on multiphase plumes’, MS Thesis, Dept. of Bergmann C. (2004), ‘Physical and Numerical studies on multiphase plumes’, MS Thesis, Dept. of Civil Engrg,, Coastal & Ocean Engrg. Program, Texas A&M University, College Station, TX.Civil Engrg,, Coastal & Ocean Engrg. Program, Texas A&M University, College Station, TX.
Bergmann C., Seol D.-G., Bhaumik T. & Socolofsky S. A. (2004), ‘Entrainment and mixing properties Bergmann C., Seol D.-G., Bhaumik T. & Socolofsky S. A. (2004), ‘Entrainment and mixing properties of a simple bubble plume’, Abstract # 272, 4th International Symposium on Environmental of a simple bubble plume’, Abstract # 272, 4th International Symposium on Environmental Hydraulics, IAHR, Hong Kong, China.Hydraulics, IAHR, Hong Kong, China.
Lemckert, C. J. & Imberger, J. (1993), ‘Energetic bubble plumes in arbitrary stratification’, Lemckert, C. J. & Imberger, J. (1993), ‘Energetic bubble plumes in arbitrary stratification’, J.Hydraulic J.Hydraulic Engrg..Engrg.. 119119(6), 680-703.(6), 680-703.
McDougall, T.J. (1978), ‘Bubble plumes in stratified environments’, McDougall, T.J. (1978), ‘Bubble plumes in stratified environments’, J.Fluid Mech.J.Fluid Mech. 8585(4), 655-672.(4), 655-672. Milgram, J.H. (1983), ‘Mean flow in round bubble plumes’, Milgram, J.H. (1983), ‘Mean flow in round bubble plumes’, J.Fluid Mech.J.Fluid Mech. 133133, 345-376., 345-376. Morton, B. R., Taylor, S. G. I. & Turner, J. S. (1956), ‘Turbulent gravitational convection from Morton, B. R., Taylor, S. G. I. & Turner, J. S. (1956), ‘Turbulent gravitational convection from
maintained and instantaneous sources’, maintained and instantaneous sources’, Proc. of the Royal Soc.Proc. of the Royal Soc. A234A234, 1-23, 1-23 Schladow, S. G.(1993), ‘Lake destratification by bubble-plume systems: Design methodology’, Schladow, S. G.(1993), ‘Lake destratification by bubble-plume systems: Design methodology’, J. J.
Hydr. Engrg.Hydr. Engrg. 119119(3), 350-368.(3), 350-368. Socolofsky S. A. (2001), ‘Laboratory Experiments of Multi-phase plumes in Stratification and Socolofsky S. A. (2001), ‘Laboratory Experiments of Multi-phase plumes in Stratification and
Crossflow’, Ph.D Thesis, Dept. of Civ. Env. Engrg., MIT, Cambridge, MA.Crossflow’, Ph.D Thesis, Dept. of Civ. Env. Engrg., MIT, Cambridge, MA. Socolofsky, S. A., Crounse, B. C. & Adams, E. E (2002), ‘Multi-phase plumes in uniform, stratified and Socolofsky, S. A., Crounse, B. C. & Adams, E. E (2002), ‘Multi-phase plumes in uniform, stratified and
flowing environments, flowing environments, inin H. Shen, A. Cheng, K.-H. Wang & M. H. teng, eds, ‘Environmental Fluid H. Shen, A. Cheng, K.-H. Wang & M. H. teng, eds, ‘Environmental Fluid Mechanics – Theories and Applications’, ASCE/Fluids Committee, Chapter 4, pp. 84-125.Mechanics – Theories and Applications’, ASCE/Fluids Committee, Chapter 4, pp. 84-125.
Wuest, A., Brooks, N. H. & Imboden, D. M. (1992), ‘Bubble plume modeling for lake restoration’, Wuest, A., Brooks, N. H. & Imboden, D. M. (1992), ‘Bubble plume modeling for lake restoration’, Water Resour. Res.Water Resour. Res. 2828(12), 3235-3250.(12), 3235-3250.
Related Links:Related Links:
http://vtchl.uiuc.edu/basic/r/bp/http://vtchl.uiuc.edu/basic/r/bp/ http://www.dantecdynamics.com/PIV/System/Index.htmlhttp://www.dantecdynamics.com/PIV/System/Index.html http://archive.greenpeace.org/politics/co2/co2dump.pdfhttp://archive.greenpeace.org/politics/co2/co2dump.pdf www.umanitoba.ca/institutes/fisheries/eutro.html www.umanitoba.ca/institutes/fisheries/eutro.html http://bss.sfsu.edu/ehines/geog646/Marine%20Pollution.pdfhttp://bss.sfsu.edu/ehines/geog646/Marine%20Pollution.pdf http://www.sealifesupply.com/aquaria.htmhttp://www.sealifesupply.com/aquaria.htm
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