Fire Technology

, Volume 52, Issue 6, pp 2093–2115

Large Eddy Simulations of the Ceiling Jet Induced by the Impingement of a Turbulent Air Plume

  • Setareh Ebrahim Zadeh
  • Georgios Maragkos
  • Tarek Beji
  • Bart Merci
Article

DOI: 10.1007/s10694-015-0561-3

Cite this article as:
Ebrahim Zadeh, S., Maragkos, G., Beji, T. et al. Fire Technol (2016) 52: 2093. doi:10.1007/s10694-015-0561-3

Abstract

In this paper, a sensitivity study is performed with FireFOAM 2.2.x for a hot air jet plume impinging onto a flat horizontal ceiling. The plume evolution and the induced ceiling flow are considered. The influence of the level of turbulence imposed at the inlet, in terms of intensity and eddy length scale, is discussed. Also, the effect of the turbulence model constant is examined. For the case considered, the best results are obtained when no sub-grid scale (SGS) model is used. If a SGS model is used, the level of turbulence at the inlet and the choice of the turbulence model constant are shown to have a significant effect on the prediction of plume’s spreading and the ceiling flow velocity. The eddy length scale at the inflow does not have significant impact on the results. Comparisons with the available experimental data indicate that FireFOAM is capable of predicting the mean velocity-field well. In the near field region, an under-estimation of the turbulent velocity fluctuations is observed, whereas reasonably good agreement is obtained in the far field.

Keywords

FireFOAM Hot air jet plume Ceiling flow LES 

List of Symbols

T

Temperature (°C)

Re

Reynolds number (–)

u

Velocity (m/s)

v

Velocity (m/s)

D

Diameter (m)

Fr

Froude number (–)

g

Gravitational acceleration (m/s2)

k

Turbulent kinetic energy (m2/s2)

p

Pressure (Pa)

Y

Mass fraction (–)

Dk

Molecular diffusivity (m2/s)

Dth

Thermal diffusivity (m2/s)

Pr

Prandtl number (–)

hs

Sensible enthalpy (J/kg)

ck

One-equation turbulence model constant (-)

cs

Smagorinsky model constant (–)

S

Strain rate (s−1)

z

Height (m)

r

Radial distance (m)

Greek

ρ

Density (kg/m3)

μ

Dynamic viscosity (kg/(m s))

ν

Kinematic viscosity (m2/s)

ε

Turbulent dissipation rate (m2/s3)

δv

Viscous sublayer (mm)

δij

Kronecker delta (–)

Subscripts

i

Inlet

m

Maximum

Ambient

t

Turbulent

Superscripts

Fluctuations

Funding information

Funder NameGrant NumberFunding Note
Vlaamse Overheid (BE)
  • 3G004912

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Setareh Ebrahim Zadeh
    • 1
  • Georgios Maragkos
    • 1
  • Tarek Beji
    • 1
  • Bart Merci
    • 1
  1. 1.Department of Flow, Heat and Combustion MechanicsGhent UniversityGhentBelgium

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