SCHEDULE AND CONTENTS OF LECTURES -- Zurich 2011
MONDAY, FEBRUARY 14 (9-12:30 and 14-17:30)
1. Introduction/Introduction to multiphase flows:
G. Hetsroni
Definition of multiphase flows; types of flow (two-phase, three-phase).
Applications; power generation, hydrocarbon recovery,
chemical processing etc. Differences to single phase flows; limiting phenomena (CHF, instability etc).
History of development of subject; principal sources of information. Nature of multiphase flows; flow patterns (movie).
2. Basic models for two-phase flows:
G. Yadigaroglu
Strategies in modelling two-phase flows. Averaging. Simplified, control-volume derivation of continuity,
momentum and energy equations for separated flows. The homogeneous flow model.
Combined equations � separated flow models; closure requirements.
Application to annular and stratified flows. The drift flux models.
3. Empirical and phenomenological models for multiphase flows I: Vertical flows:
G.F. Hewitt
Empirical correlations for frictional pressure gradient and void fraction.
Phenomenological models: Bubble flow, bubble/slug transition.
Slug flow. Flooding (CCFL) and the slug churn transition. Churn flow.
Churn/annular transition. Annular flow. Wispy annular flow.
4. Empirical and phenomenological models for multiphase flows II:
Horizontal and inclined flows:
G.F. Hewitt
Empirical correlations for frictional pressure gradient and void fraction in
horizontal and inclined flows. Phenomenological models for horizontal flows:
Stratified flow. Stratified/slug transition. Slug flow. Stratified/slug/annular transition.
Annular flow. Critical two-phase flow.
TUESDAY, FEBRUARY 15 (9-12:30 and 14-17:30)
5. Phase change heat transfer (single component systems):
G. Hetsroni
Boiling heat transfer (movie); nucleation and nucleate boiling, forced convection evaporation.
Correlations and models. Dryout (critical) heat flux: mechanism and predictions.
6. Empirical and phenomenological models for multiphase flows III: Flows with phase change:
G.F. Hewitt
Single component systems; heat transfer regimes, heat transfer in slug flow
(equilibrium, non-equilibrium); heat transfer in annular flow, correlations, mechanisms, models
(overall, detailed, effect of nucleate boiling). Multicomponent systems (droplet effects).
Dryout (critical) heat flux; low quality (bubbly) and high quality (annular) flows. Condensation; similarities
and differences to evaporation.
7. Thermal non-equilibrium flows:
G. Yadigaroglu
Importance of departures from mechanical and thermal equilibrium. Computation of
non-equilibrium flows. Subcooled boiling. Post-dryout heat transfer; 3D effects.
8. Multifield models:
S. Banerjee
The need for multifield models.
Interpenetrating continua and Lagrangian-Eulerian approaches.
Closure requirements. One-dimensional form - structure, strengths, and weaknesses.
Multidimensional aspects - applicability and limitations.
WEDNESDAY, FEBRUARY 16 (9-12:30 and 14-17:30)
9. Advanced two-phase flow instrumentation:
H.-M. Prasser
Instrumentation for gas fraction, velocity and interfacial area. Local probes and mesh sensors.
Tomographic methods. Optical methods. Ultrasonic sensors.
10. Instabilities in two-phase flow:
G. Yadigaroglu
Instabilities of the liquid-gas interface; applications to jets, particles,
etc. Two-phase system instabilities; fundamentals, mechanisms. Computational
tools, stability maps. BWR stability.
11. Experiments to develop closure relations for two-fluid models:
H.-M. Prasser
Interfacial momentum transfer in bubbly flow; forces acting on bubbles.
Bubble coalescence and break-up. Turbulence modulation.
Interfacial heat transfer, condensation, boiling.
12. Numerical methods:
S. Banerjee
Introduction. Initial and boundary conditions. Method of characteristics.
Finite difference methods. Stability. Explicit and implicit methods. Methods used in computer codes.
PART IIA. NEW REACTOR SYSTEMS AND METHODS
THURSDAY, FEBRUARY 17 (9-12:30 and 14-17:30)
13A. Multiphase phenomena in LWRs I:
G. Yadigaroglu
Loss-of-coolant accidents, transients and their simulation; uncertainty
evaluation. In-vessel accident phenomenology; modelling of core cooling. Passive
emergency core and containment cooling.
14A. Heat transfer in nuclear fuel elements:
G.F. Hewitt
Critical heat flux in rod bundle geometries and prediction methods: global models, sub-channel methods, phenomenological models;
effects of non-uniform heat flux distribution; grid design for enhancement. Reflood heat transfer; clad ballooning, droplet/surface interactions, rewetting.
15A. Multiphase phenomena in LWRs II:
M.L. Corradini
Multiphase phenomena during severe accidents: vapour explosions, molten core
quenching and coolability, etc. Severe accident codes; system analyses and simulation.
16A. Closure laws in nuclear systems codes:
D. Bestion
Development and validation of closure laws dependent on flow regime.
Hydrodynamic and heat transfer closure relationships in system codes and their limitations.
Predicting choked flow, stratified flow, CCFL.
FRIDAY, FEBRUARY 18 (8:30-12:30)
17A. Advanced LWR concepts and phenomena:
M.L. Corradini
Review of advanced LWR concepts for near-term and Generation IV reactor development.
Two-phase phenomena in passive safety systems (natural circulation, condensation, critical flow).
18A. Advanced reactor systems:
M.L. Corradini
Overview of Generation IV liquid-metal and gas reactor systems. Multiphase flow
issues: direct-contact heat transfer, solid-gas fluidisation, steam generator
considerations.
19A. Advanced computational modelling of nuclear systems:
D. Bestion
Needs of advanced simulation tools for thermalhydraulic issues.
New models for system codes: Multi-field models, dynamic interfacial area and turbulence prediction.
Use of CMFD for nuclear reactor investigations.
PART IIB. COMPUTATIONAL MULTI-FLUID DYNAMICS (CMFD)
THURSDAY, FEBRUARY 17 (9-12:30 and 14-17:30)
13B. Introduction to CMFD:
G. Tryggvason.
Need for numerical simulations and history. Overview of the governing equations and standard solution methods. Introduction to the various methods used to track sharp fluid interfaces.
14B. Computational modelling of turbulent multiphase flows:
D. Lakehal
Multidimensional, multifluid modelling. Turbulence in multiphase flows: scale separation; averaging and filtering;
methods for low and high Reynolds numbers - from RANS to LES; coupled sub-scale approaches.
15B. Direct simulations of multiphase systems:
S. Banerjee
Interfacial boundary conditions. The ghost fluid and Level Set methods.
Numerical issues and developments. Boundary fitting. Direct numerical simulations of
separated and dispersed flows.
16B.Volume of Fluid (VOF) Method:
S. Zaleski
Volumetric tracking, piecewise linear interface reconstruction.
Advanced VOF methods: unsplit, exactly-conserving VOF methods, oct-tree adaptive mesh refinement.
Recent advances in surface tension with VOF methods: height-function methods.
FRIDAY, FEBRUARY 18 (9-12:30)
17B. Applications of VOF and Lattice Gas Cellular Automata:
S. Zaleski.
Flows with large interface deformation and disruption. Ligament formation, atomization and entrainment.
Droplet splashing. Multiphase flow in porous media.
Introduction to Lattice Gas Cellular Automata and Multiphase Lattice Boltzmann.
18B. Embedded Interface Methods:
G. Tryggvason.
Interface tracking for direct numerical simulations (DNS) of multiphase flows.
Applications to bubbly flows and flows with phase change and mass transfer. Multiscale issues.
PART III. CMFD WITH COMMERCIAL CODES
FRIDAY, FEBRUARY 18 (13:30-17:30)
20. Modelling of industrial multiphase flows with STAR-CD:
S. Lo
A selection of examples illustrating some of the challenges and advanced models
used in the analyses of industrial multiphase flow problems.
21. Modelling of multiphase flow with ANSYS CFD:
Sergio A. Vasquez
Solver technology overview of model portfolio: Euler/Euler, free surface flow, applicability and limitations. Applications and comparisons to data.
22. Simulating Industrial Multiphase Flows with TransAT:
D. Lakehal
Solver, models and algorithms. Examples and validation using the Eulerian-Eulerian field approach,
Level Set and VOF, Lagrangian particle tracking and three-phase flows.
NB: Following the short courses, but independently, ASCOMP GmbH is offering training on its TransAT code on Saturday February 19,
on a first-come first-served basis (number of participants limited to 25;
course fee: 100 EUR including lunch, refreshments and materials - please, do not remit to Short Course account).
Please indicate your interest on the registration form and you will receive confirmation from ASCOMP.
Back to the top
Feedback
Multiphase ShortCourse, Parts / last update: 06-Dec-2010 (GY)