Modeling Standards and Recommendations

Modeling standards for Spray G have been identified to describe liquid and vapor penetrations and other parameters in a consistent way. CFD Groups (Argonne National Lab (ANL), Politecnico di Milano (Polimi), University of Wisconsin – Madison (UW)) for ECN3 have picked metrics that will be used for comparison of modeling results. CFD activities should be performed and post-processed according the following standard definitions and recommendations. Please also see Spray G under ECN3 proceedings for more information.


  1. Liquid Penetration
    • % Liquid volume fraction threshold
  2. Vapor Penetration
    • % Mixture fraction threshold

Liquid and vapor penetrations measured along the injector axis, see below figure 3. Zero point is set at the injector tip.


Figure 3: Penetration length 

Mixture fraction and sauter mean diameter (SMD) profile locations are defined as below:

1. Spray Axis- Along center line of an individual jet (zero at injection location, positive towards spray tip), figure 4.


Figure 4: Jet Axis 
2. Injector Axis – Along the injector axis (zero at nozzle tip, positive towards leading edge), figure 5.


Figure 5: Injector axis 
3. Cross-section plane
  • Plane normal to injector axis
  • Located 15 mm downstream of injector tip measured along injector axis
  • Radial cross-section: along a radial line through the spray axis center point (zero at injector axis, positive outward), figure 6.


Figure 6: Radial cross-section 
  • Transverse cross-section: across the spray perpendicular to the radial line (zero at spray center point and positive direction clockwise as viewed from injector), figure 7


    Figure 7: Transverse cross-section 
    4. Dual-plume cross-section (this is for understanding plume-to-plume interaction), figure 8.
    • Taken along a line connecting the center-points of two neighboring spray plumes
    • Zero at center of counter-clockwise-most (as viewed from injector) plume
    • Positive towards second plume (clockwise as viewed from injector)