AFDM: An Advanced Fluid-Dynamics Model

Technical Report · Sat Sep 01 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/6599591· OSTI ID:6599591

Berthier, J ^[1]; Wilhelm, D ^[2]; Bohl, W R ^[3]

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1. CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)
2. Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik
3. Los Alamos National Lab., NM (USA)

This report consists of three parts. First, for the standard Advanced Fluid-Dynamics Model (AFDM), heat-transfer coefficients between components are worked out, depending on the different possible topologies. Conduction, convection, and radiative heat-transfer mechanisms are modeled. For solid particles, discontinuous phases that obey a rigid'' model, and components lacking relative motion, heat transfer is by conduction. Convection is represented for fluids in motion inside circulating'' bubbles and/or droplets. Radiation is considered between droplets in vapor continuous flow. In addition, a film-boiling model has been formulated, where radiation provides the lower limit on the fuel-to-coolant heat-transfer coefficient. Second, the momentum-exchange coefficients are defined for the standard AFDM. Between a continuous and discontinuous phase, the model consists of both laminar and turbulent terms. The most important feature is the drag coefficient in the turbulent term. It is calculated by a drag similarity hypothesis with limits for large Reynolds numbers, distorted particles,'' and churn-turbulent flow. A unique hysteresis algorithm exists to treat the liquid continuous to vapor continuous transition. Two discontinuous components are coupled using a turbulent term with an input drag coefficient. Fluid- structure momentum exchange is represented with a standard friction-factor correlation. Third, the formulas used for the AFDM simplified Step 1 models are discussed. These include the heat-transfer coefficients, the momentum-exchange functions, and the manner in which interfacial areas are determined from input length scales. The simplified modeling uses steady-state engineering correlations, as in SIMMER-II.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOD; USNRC
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6599591
• Report Number(s): LA-11692-MS-Vol.3; ON: DE90017537
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
FLUID FLOW
A CODES
HEAT TRANSFER
ALGORITHMS
CONVECTION
DRAG
HYSTERESIS
MOMENTUM TRANSFER
PHASE TRANSFORMATIONS
REYNOLDS NUMBER
THERMAL CONDUCTION
TURBULENCE
COMPUTER CODES
ENERGY TRANSFER
MASS TRANSFER
MATHEMATICAL LOGIC
640410* - Fluid Physics- General Fluid Dynamics
990200 - Mathematics & Computers