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Gasoline Spray (Spray G)Topic 3.5 Internal flow modeling

Ron Grover (GM)

Spray G – Internal Flow Modeling

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Outline• Model setup and assumptions• Mass flow calculations• Nozzle exit velocity field• Summary and discussion

Overview

Research Questions• Can we actually get results?• What is a representative discharge coefficient injector?• What is the flow field exiting the injector?• What is the deviation in mass flow per hole?

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ECN• Fluid Solver HRMFoam (c/o UMass)• Turbulence k-epsilon• Assumptions Submerged Fluid, Incompressible,

Isenthalpic• Meshing 414,000 cells • Mesh Topology Polyhedral (STAR-CCM+)

2 layer extrusion on wall• Needle Motion None. Fixed maximum lift 45 µm

Cell size ~ 30 – 65 µm

Nozzle cell size ~ 20-30 µm

Spray G – Model Setup

L/D ~ 1 (nozzle)

L/D ~ 1.2 (c-bore)

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Predicted CD ~ 0.50 Cv ~ 0.73 CA ~ 0.69

Spray G – Run to Steady State

GM Measurement CD ~ 0.52

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ECN Spray G – Internal Flow Results

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Counterbore Exit

Time=2.8ms

Nozzle Hole Exit

Spray G – Velocity Cut Planes

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Hole % Flow CD Deviation (%)

1 12.0 0.50 -3.65

2 12.2 0.50 -2.10

3 12.5 0.52 0.34

4 14.1 0.58 13.01

5 11.4 0.47 -8.96

6 11.5 0.47 -8.30

7 14.5 0.60 16.10

8 11.7 0.48 -6.44

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Time=2.8ms

Discharge Coefficient Per Hole

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Hole % Flow CD Deviation (%)1 12.0 0.50 -3.65

2 12.2 0.50 -2.10

3 12.5 0.52 0.34

4 14.1 0.58 13.01

5 11.4 0.47 -8.96

6 11.5 0.47 -8.30

7 14.5 0.60 16.10

8 11.7 0.48 -6.44

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Discharge Coefficient Per Hole

Time=2.8ms

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Initial Findings• CFD calculations show that deficit in discharge coefficient is

equally attributed to both a velocity and area deficit• The velocity distribution per hole is biased towards the side of

the hole closest to the injector axis• An instantaneous snapshot of discharge coefficient per hole

shows variation; a finding that requires further investigation

Call for Additional Contributions!• Solicit various modeling approaches (1-fluid, 2-component, etc. )• Increased mesh resolution• Effect of plenum size• Needle motion effects• Internal-to-external nozzle flow coupling

Summary & Discussion Points

Thank-You