Combustion model types

A large number of combustion models are present in literature and a number of them have been implemented in various forms in CFD codes. In short, they can be categorised in the following families:

• Presumed PDF model
• Flame surface density model
• Eddy Dissipation Concept

Especially the first model type, the presumed PDF models, has gained a lot of popularity over the last years with the emergence of flamelet-based combustion models like RIF [1], FGM [2] and FPI [3]. Combinations of these model types can also be found, in for example the ECFM-3Z [4] and ECFM-CLEH [5] models.

Choosing the right combustion model

The choice of a particular model should be based on the capability of the model to capture the physics of the problem considered. For example, the characteristics of the problem may involve a lifted flame, as illustrated by the image on the right. If the turbulent combustion model does not contain the basic physics which are able to adequately capture the flame lift-off, it will certainly not have any predictive capability for pollutant emissions. In other words, the basic physics must be right.

In order to select the appropriate model, both experience and expertise are required to judge the applicability of a certain model to a given combustion problem. Dacolt engineers have MSc or PhD level knowledge of turbulent combustion modelling and cumulate years of experience in the use, development and implementation of turbulent combustion models, in various industries, involving steady or unsteady combustion, non-premixed or (partially) premixed combustion, single or multi-phase combustion.

References

1. N. Peters, Turbulent Combustion. Cambridge University Press, 2000.
2. J.A. van Oijen, F.A. Lammers, L.P.H. de Goey, Combust. Flame 127(3) (2001) 2124–2134.
3. O. Gicquel, N. Darabiha, D. Thevenin, Proc. Combust. Inst. 28 (2000) 1901–1908.
4. O. Colin et al., Oil Gas Sci. Technol. 58 (1) (2003) 47–62.
5. G. Subramanian et al., SAE Technical Paper Series 2007-01-0154.

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