1. Spray-Turbulence Interaction
Anne Kösters
Ph.D. student

2. Spray-Turbulence Interaction
PhD student: Anne Kösters
Project start: February 2010
Project finish: November 2014
Financed by:
Budget/ year: SEK

3. Background Diesel Spray T ~ 900 K Pgas= 60 bar Pinj = 1350 bar
Experiments done in Chalmers Spray Rig by Chengjun Du

4. Goal
Goal is to investigate spray-turbulence and turbulence-chemistry interaction, and to incorporate the findings into spray combustion models.
Approach
Implementation and improvement of models to predict spray formation (VSB2) and turbulence-chemistry interaction (VRFM, RIF) in OpenFOAM®
Detailed investigation of Diesel spray behavior and flame structure, maintained by the implemented models

5. Modeling of an evaporating spray with combustion
CFD solution
(gas)
Liquid phase
Chemistry
Spray modeling
Combustion modeling

6. Method: VSB2 Spray Model
Kösters, A. & Karlsson, A., ”A Comprehensive Numerical Study of Diesel Fuel Spray Formation in OpenFOAM”, SAE Technical Paper, , 2011.
Journal Paper (submitted to Atomization and Sprays):
Kösters, A. and Karlsson, A., ”The VSB2 spray model validated against Spray A and Spray H”

7. Experiments: Chalmers HP/HT Spray Rig
by Raúl Ochoterena
Pinj = 600bar
Pgas = 30 bar
Tgas = 500 °C
Pinj = 600bar
Pgas = 70 bar
Tgas = 500 °C
Pinj = 1200bar
Pgas = 30 bar
Tgas = 500 °C
Pinj = 1200bar
Pgas = 70 bar
Tgas = 500 °C

8. Baseline condition ECN*: liquid penetration vs time
ρ = 22.8 kg/m3; T = 900 K; pinj = 150 MPa
Spray A:
n-dodecane
Ignition delay (baseline)
Flame
lift-off
*ECN : Engine Combustion Network, results from Workshop 3, 2014

9. Baseline condition: axial mixture fraction at 1.5 ms
Pure vapor region
Liquid + Vapor region

10. Method: WS, VRFM+ and mRIF* model
Combustion
Method: WS, VRFM+ and mRIF* model
+ Kösters, A. , Golovitchev, V. & Karlsson, A., ”A Numerical
Study of the Effect of EGR on Flame Lift-off in n-Heptane Sprays Using a Novel PaSR Model Implemented in OpenFOAM”, SAE International Journal of Fuels and
Lubricants, vol. 5 no , May 2012.
Journal Paper (submitted to Combustion Theory and Modelling):
+ Kösters, A., Karlsson, A., Oevermann, M., D’Errico, G. and Lucchini, T. ,” RANS predictions of turbulent diusion ames: comparison of a reactor and a amelet combustion model to the well stirred approach”
*Pitsch, H., Wan, Y.P. & Peters, N. ”Numerical Investigation of Soot Formation and Oxidation Under Diesel Engine Conditions”, SAE Paper , 1995.
*Peters, N., Turbulent Combustion, Cambridge University Press, 2000.

11. Comparison of combustion models
mRIF
VRFM WS
Chemistry
Yi(Z,t)
(decoupled from flow field)
Yi(x,y,z,t)
Computational costs
cheap
high
Computational
cell
reactor
Computational
cell
flamelet
30 flamelets

12. ECN data of n-heptane spray combustion (spray H)
Experiments:
ECN data of n-heptane spray combustion (spray H)
Ignition delay
Lift-off length

13. Ignition delay
Lift-off length
Lift-off length
10% O2

14. Tgas = 1000 K, pgas = 42 bar, O2 = 10 %
Combustion

15. Summary PhD Project
VSB2 spray model implemented in OpenFOAM 1.6.x and 2.0.x
VSB2 spray model further developed
Validation against experimental data of Chalmers HP/HT Spray Rig
Validation against ECN data
Comparison with other groups/models within the ECN
Further results (sensitivity studies) are published
VRFM implemented in OpenFOAM 1.6.x and 2.0.x
VRFM further developed
Detailed comparison to the direct chemistry approach and the multiple RIF model

16. My Future Work Defense of Ph.D. at November 7th
Studying and understanding the processes close to the nozzle exit
Multi-component evaporation
Coupling of premixed and diffusion combustion models
(others)Future Work

17. Thank you for your attention