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GFSD combustion model

Introduction

The Generalized Flame Surface Density (GFSD) combustion model is aimed at modelling auto-ignition and combustion in Direct Injection Diesel Engines. This work was performed by F. Tap as an Ecole Centrale Paris PhD research project, sponsored by PSA Peugeot Citroën (France).

Objectives

The objective of the thesis was to improve the predictability of a combustion model for ignition delay and localisation as well as the physically representative description of flame development.

Benchmark Cases

The main test case was a lifted Diesel jet flame in a constant volume vessel, with representative ambient conditions.

Methodology

A new combustion model was developed [1,2,3], using Direct Numerical Simulation (DNS) results, bibliographical research, laminar flame computations and experimental results. The model is based on the Coherent Flame Model [4] and the Representative Interactive Flamelet [5] approaches.

Results

The new modelling approach proved to be able to simulate the experimentally observed average lift-off vs. liquid fuel penetration trade-off [6]. The predictability of the model for ignition location and delay proved to be very satisfying over a range of operating conditions. Extension of the model to simulate a Diesel engine combustion cycle has been achieved in a follow-on project.

The animation below is a CFD simulation of the ignition and stabilisation process of a Diesel spray flame in a constant volume vessel. Shown are mean mixture fraction, mean temperature, mean flame surface density and average heat release rate in the volume. The model reproduces the 'premixed spike' following the ignition event, where the premixed mixture is rapidly burned, followed by a stabilisation of the lifted flame.

Click to stop and control the animation. Use the 'p' key for play, 's' for stop, 'f' for moving 1 frame forward and 'b' for moving 1 frame back.

References

  1. F.A. Tap and D. Veynante, Proc. Combust. Inst. 30:919-926 (2005).
  2. Tap, F., Hilbert, R., Thévenin, D., and Veynante, D. Combust. Theory Modelling, 8:165-193 (2004).
  3. Hilbert, R., Tap, F., Thévenin, D., and Veynante, D. Proc. Combust. Inst., 29:2079-2085 (2002).
  4. T. Poinsot and D. Veynante, Theoretical and numerical combustion. R. T. Edwards, 2001.
  5. N. Peters, Turbulent Combustion. Cambridge University Press, 2000.
  6. D. Siebers and B. Higgins, SAE Technical Paper Series 2001-01-0530 (2001).