Advanced Photon Source, Argonne National Laboratory
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This work and the use of the APS were supported by US Department of Energy, Office of Science/Basic Energy Science and Energy Efficiency and Renewable Energy/Vehicle Technology Ultrafast X-ray Study of Multi-Orifice Diesel Nozzle Spray : Flow Dynamics and Breakup in the Near-Field Advanced Photon Source, Argonne National Laboratory Motivation Deficient information on near-nozzle flow dynamics and breakup of multi-orifice nozzle sprays for validation of conventional breakup models Objectives Interpretation of near-field flow dynamics and breakup of multi-orifice nozzle spray Provide the validation data for conventional and future breakup models Overall Flow Development Principle of X-ray Phase-Enhanced Imaging Ref.) S. W. W ilkins et al. , Nature , 384 (28), 335-338,1996 Diffracted Beams MultipleInterference Interference sample DetectedIntensity Broad Sharp Polychromatic X-ray Beam Absorption-contrasted Phase-contrasted Branching Multi-Jet Flows Wavy Instabilities and Membrane-Mediated Breakup Single-Exposed (Side-View) P inj = 30MPa, Fuel = Biodiesel Needle Lift = 350 m, Ambient Gas = N 2 Two-Orifice Diesel Nozzle R evolution tim e :3.682 s 16 m A 11 m A foreach 1.594 s Hybrid-SingletMode 3.682 Tim e ( s) C urrent (m A) 1.594 1.594 single-exposure double-exposure Periodicity : 68ns Experiments (Setup in XOR 7ID-B, APS ANL) X-ray Pulses for Single- and Double-Exposure Imaging Features Breakup Process of Multi-Jet-Flows Single-Exposed (Top-View) 1. Wavy Instabilities Thin Membranes Instability Frequency Instability1 : 2.8 MHz Instability2 : 4.2 MHz Originated from different inter-nozzle flows Double-Exposed (Side-View) x=3.5 mm Dynamics of Thinned Membranes C v Membrane : 0.73 Downflow : 0.84 Air drag exerted on membranes 2. Breakup of Membranes Single-Exposed (Top-View) Membranes breakup earlier than cylindrical flows. 3. Breakup of Cylindrical Flows Single-Exposed (Side-View) Cylindrical flows breakup directly into ligaments. Dynamics of Multi-Jet-Flows Double-Exposed (Side-View) P inj = 40MPa* Axial Location (x) = 2.5 mm C v (V/V ideal ) = 0.87 V x,up = 273.53 m/s V y,up = 8.21 m/s V x,down = 273.53 m/s V y,down = -10.94 m/s Autocorrelation Local branching flows have same axial velocity but different penetration di Structure of Multi-Jet-Flows 0 100 200 300 400 500 600 0.00 0.05 0.10 0.15 0.20 N o rm a lize d P DF JetW id th [ m] S ide-view T o p-vie w top-view side-view Single-Exposed Axial Location (x) = 3.5 mm Local cylindrical (1) & tubular (2) Flows 1 2 Elliptical Spray (56 %) : (a) + (d Stretch of spray up and down Comprised of cylindrical flows Spray width Hollow Spray (44 %) : (a) + (b) Hollow region inside spray Comprised of tubular and cylindrical flows Side View Top View Stable elliptical spray was observed from another nozzle with 700 m need Full hollow-cone spray was observed with 50 m needle-lift. The sprays with 350 m needle-lift in this study are in transient stage o full hollow-cone to stable elliptical spray. Top Needle-Lift = 350 m 0 1 2 3 6 (mm) Summary Development and breakup of multi-orifice nozzle spray are dictated by branching multi-jet-flows induced by complex inter-nozzle flows. In the near-field, branching jet-flows with same axial velocity and have cylindrical or tubular structures were observed and these formed elliptical spray in one case and hollow circular spray in another. At downstream, wavy instabilities associated with branching jet-flows appear on the spray and develop into thin membranes. The thinned membranes breakup first into ligaments by aerodynamic drag and then cylindrical flows breakup later at farther downstream.
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Ultrafast X-ray Study of Multi-Orifice Diesel Nozzle Spray : Flow Dynamics and Breakup in the Near-Field. Advanced Photon Source, Argonne National Laboratory. Principle of X-ray Phase-Enhanced Imaging. Motivation - PowerPoint PPT Presentation
Transcript of Advanced Photon Source, Argonne National Laboratory
This work and the use of the APS were supported by US Department of Energy, Office of Science/Basic Energy Science and Energy Efficiency and Renewable Energy/Vehicle Technology
Ultrafast X-ray Study of Multi-Orifice Diesel Nozzle Spray : Flow Dynamics and Breakup in the Near-Field
Advanced Photon Source, Argonne National Laboratory
Motivation Deficient information on near-nozzle flow dynamics and breakup of multi-orifice nozzle sprays for validation of conventional breakup models
Objectives Interpretation of near-field flow dynamics and breakup of multi-orifice nozzle spray Provide the validation data for conventional and future breakup models
Overall Flow Development
Principle of X-ray Phase-Enhanced Imaging
Ref.) S. W. Wilkins et al., Nature, 384 (28), 335-338, 1996
DiffractedBeams
Multiple Interference
Interference
sample
Detected Intensity
Broad
Sharp
Polychromatic X-ray Beam
Absorption-contrasted
Phase-contrasted
Branching Multi-Jet Flows Wavy Instabilities and Membrane-Mediated Breakup
Single-Exposed (Side-View) Pinj = 30MPa, Fuel = Biodiesel
Needle Lift = 350 m, Ambient Gas = N2
Two-Orifice Diesel Nozzle
Revolution time: 3.682 s
16 mA
11 mA for each
1.594 s 1.594 s
Hybrid-Singlet Mode
3.682
Time (s)
Current(mA)
1.594 1.594
single-exposure double-exposure
Periodicity : 68ns
Experiments(Setup in XOR 7ID-B, APS ANL)
X-ray Pulses for Single- and Double-Exposure Imaging
Features
Breakup Process of Multi-Jet-Flows
Single-Exposed(Top-View)
1. Wavy Instabilities Thin Membranes
Instability Frequency Instability1 : 2.8 MHz Instability2 : 4.2 MHz
Originated from different inter-nozzle flows
Double-Exposed (Side-View)
x=3.5 mm
Dynamics of Thinned Membranes
Cv Membrane : 0.73 Downflow : 0.84
Air drag exerted on membranes
2. Breakup of Membranes Single-Exposed(Top-View)
Membranes breakup earlier than cylindrical flows.
3. Breakup of Cylindrical Flows Single-Exposed(Side-View)
Cylindrical flows breakup directly into ligaments.
Dynamics of Multi-Jet-FlowsDouble-Exposed
(Side-View) Pinj = 40MPa*
Axial Location (x) = 2.5 mm
Cv(V/Videal) = 0.87
Vx,up = 273.53 m/sVy,up = 8.21 m/s
Vx,down = 273.53 m/sVy,down = -10.94 m/s
Autocorrelation
Local branching flows have same axial velocity but different penetration directions.
Structure of Multi-Jet-Flows
0 100 200 300 400 500 6000.00
0.05
0.10
0.15
0.20
Nor
mal
ized
PD
F
Jet Width [m]
Side-view Top-viewtop-view
side-view
Single-ExposedAxial Location (x) = 3.5 mm
Local cylindrical (1) & tubular (2) Flows
1
2
Elliptical Spray (56 %) : (a) + (d) Stretch of spray up and down Comprised of cylindrical flows
Spray width
Hollow Spray (44 %) : (a) + (b) Hollow region inside spray Comprised of tubular and cylindrical flows
SideView
TopView
Stable elliptical spray was observed from another nozzle with 700 m needle-lift. Full hollow-cone spray was observed with 50 m needle-lift. The sprays with 350 m needle-lift in this study are in transient stage of full hollow-cone to stable elliptical spray.
Top Needle-Lift= 350 m
0 1 2 3 6(mm)
Summary Development and breakup of multi-orifice nozzle spray are dictated by
branching multi-jet-flows induced by complex inter-nozzle flows. In the near-field, branching jet-flows with same axial velocity and have
cylindrical or tubular structures were observed and these formed ellip-tical spray in one case and hollow circular spray in another.
At downstream, wavy instabilities associated with branching jet-flows appear on the spray and develop into thin membranes. The thinned membranes breakup first into ligaments by aerodynamic drag and then cylindrical flows breakup later at farther downstream.
