Turbulence modelling of turbulent buoyant jets and compartment fires

Show simple item record

dc.contributor.advisor Rubini, Philip A. en_UK
dc.contributor.author Sanderson, V. E. en_UK
dc.date.accessioned 2005-11-23T14:33:36Z
dc.date.available 2005-11-23T14:33:36Z
dc.date.issued 2001-02 en_UK
dc.identifier.uri http://hdl.handle.net/1826/137
dc.description.abstract Turbulent buoyant jets are a major feature in fire hazards. The solution of the Reynolds Averaged Navier-Stokes (RANS) equations through computational fluid dynamic (CFD) techniques allow such flows to be simulated. The use of Reynolds averaging requires an empirical model to close the set of equations, this is known as the turbulence model. This thesis undertakes to investigate linear and nonlinear approaches to turbulence modelling and to apply the knowledge gained to the simulation of compartment fires. The principle contribution of this work is the reanalysis of the standard k- ε turbulence model and the implementation and application of more sophisticated models as applied to thermal plumes. Validation in this work, of the standard k- ε model against the most recent experimental data, counters the established view that the model is inadequate for the simulation of buoyant flows. Examination of previous experimental data suggests that the measurements were not taken in the self-similar region resulting in misleading comparisons with published numerical solutions. This is a significant conclusion that impacts of the general approach taken to modelling turbulence in this field. A number of methods for modelling the Reynolds stresses and the turbulent scalar fluxes have been considered and, in some cases for the first time, are applied to nonisothermal flows. The relative influence of each model has been assessed enabling its performance to be gauged. The results from this have made a valuable contribution to the knowledge in the field and have enabled the acquired experience to be applied to the simulation of compartment fires. The overall conclusion drawn from this thesis is that for the simulation of compartment fires, the most appropriate approach with current computational resources, is still the buoyancy corrected standard k- ε model. However, the turbulence scalar flux should be modelled by the generalised gradient diffusion hypothesis (GGDH) rather than the eddy-diffusivity assumption. en_UK
dc.format.extent 1883 bytes
dc.format.extent 10668634 bytes
dc.format.mimetype text/plain
dc.format.mimetype application/pdf
dc.language.iso en_UK en_UK
dc.publisher Cranfield University en_UK
dc.relation.uri http://www.cranfield.ac.uk/~p.a.rubini en_UK
dc.subject.other Turbulence modelling en_UK
dc.subject.other Computational fluid dynamics en_UK
dc.subject.other Fire plumes en_UK
dc.title Turbulence modelling of turbulent buoyant jets and compartment fires en_UK
dc.type Thesis or dissertation en_UK
dc.type.qualificationlevel Doctoral
dc.type.qualificationname PhD
dc.publisher.department School of Mechanical Engineering

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search CERES


My Account