文档介绍：Modeling of Two-phase Flow and Boiling
with FLUENT
by
Nilanjana Basu, Andrey Troshko, and Greg Nurnberg
Fluent Inc.
Lebanon, New Hampshire
Presented at RELAP5 UGM, West Yellowstone, Montana
July 27, 2003
1
Outline
• FLUENT & RELAP5-3D© Coupling
• Multiphase models in FLUENT
• Boiling and two-phase flow Case studies
with FLUENT
• Summary
2
FLUENT & RELAP5-3D© Coupling
Advantages
• Model entire system using 1
dimensional features of RELAP5-
3D©
• Model ponents of the
system in detail using the 3
dimensional features of FLUENT
• Both the system ponent
behavior is more accurately
predicted
• Boundary condition information
is transferred back and forth
between the two codes
3
FLUENT & RELAP5-3D© Coupling (contd.)
Some key modeling capabilities in FLUENT to be utilized:
– Turbulence
– Two-phase flow
– Flow through packed bed
– Neutronics-fluid interaction in the core region
Focus of this presentation: Two-phase flow
4
Multiphase models in FLUENT
• Discrete Phase Model (DPM)
• Mixture Model
• Volume of Fluid Model (VOF)
• Eulerian Multiphase Flow Model
5
Multiphase models in FLUENT (contd.)
Discrete Phase Model (DPM)
• Trajectories of particles/droplets/bubbles puted in a Lagrangian
frame.
–Particles can exchange heat, mass, and momentum with the
continuous gas phase.
–Particle-Particle interaction is neglected.
–Turbulent dispersion can be modeled with stochastic tracking or a
“particle cloud” model.
• Volume loading: volume fraction < 12%)
• Particulate Loading: Low to moderate.
Application examples: Cyclones, spray dryers, particle separation and
classification, aerosol dispersion, liquid fuel and bustion. etc.
6
Multiphase models in FLUENT (contd.)
The Mixture Model
– Modeling N-phase flows.
– Solves the mixture momentum equation (for mass-averaged
mixture velocity)
• Inter-phase exchange terms depend on relative (slip) velocities
• Turbulence and