- Author
- Liew, S. K. | Moss, J. B.
- Title
- Buoyant Fire Modelling.
- Coporate
- Cranfield Institute of Technology, Bedford, England
- Report
- TP-84-2, 1984, 64 p.
- Keywords
- fire models | flame models | laminar flames | turbulence | buoyancy | temperature field | burners
- Identifiers
- flamelet model for buoyant reacting flows
- Abstract
- This report describes a detailed investigation of buoyant fire modelling using the laminar flamelet approach. Alternative models are briefly reviewed and a k-e turbulence model, incorporating the influence of buoyancy, is introduced into a parabolic calculation. Predictions are compared with the extensive experimental data of Walker (1984) for a simulated fire established on a porous refractory burner. Encouraging agreement is found for predictions initiated from measured profiles at 14 cm downstream from the burner exit plane. The very early part of the flame, strongly influenced by a large scale, low frequency buoyant instability, is poorly reproduced. The results suggest that the scalar modelling, in particular the form of the mixture fraction probability density function, has a significant effect on flame development. The temperature field emerges to be a more sensitive test of the computational modelling than does the velocity. Uncertainties in measured temperature fluctuation levels are highlighted. Recommendations are made for model improvements in the next phase of the programme.