Spray-Turbulence Interaction Anne Kösters Ph.D. student

Spray-Turbulence Interaction PhD student: Anne Kösters Project start: February 2010 Project finish: November 2014 Financed by: Budget/ year: 1 090 000 SEK

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

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

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

Method: VSB2 Spray Model Kösters, A. & Karlsson, A., ”A Comprehensive Numerical Study of Diesel Fuel Spray Formation in OpenFOAM”, SAE Technical Paper, 2011-01-0842, 2011. Journal Paper (submitted to Atomization and Sprays): Kösters, A. and Karlsson, A., ”The VSB2 spray model validated against Spray A and Spray H”

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

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 www.sandia.gov/ecn

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

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. 2 604-610, 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 952357, 1995. *Peters, N., Turbulent Combustion, Cambridge University Press, 2000.

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

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

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

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

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

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

Thank you for your attention