Two-phase flow modeling with discrete particles

Conference · Mon Mar 23 04:00:00 EST 1992

OSTI ID:10166730

Mortensen, G A ^[1]; Trapp, J A ^[2]

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1. EG and G Idaho, Inc., Idaho Falls, ID (United States)
2. Colorado Univ., Denver, CO (United States)

The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase flow analysis are based on equations that have been averaged over control volumes. These models average out the detailed description within the control volumes and rely on flow regime maps to determine the distribution of the two phases within a control volume. Flow regime maps depend on steady state models and probably are not correct for dynamic models. Numerical simulations of the averaged two-phase flow models are usually performed using a two-fluid Eulerian description for the two phases. Eulerian descriptions have the advantage of having simple boundary conditions, but the disadvantage of introducing numerical diffusion, i.e., sharp interfaces are not maintained as the flow develops, but are diffused. Lagrangian descriptions have the advantage of being able to track sharp interfaces without diffusion, but they have the disadvantage of requiring more complicated boundary conditions. This paper describes a numerical scheme and attendant computer program, DISCON2, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between the intractable local instantaneous and the averaged two-fluid model. This new model uses a combination of an Eulerian and a Lagrangian representation of the two phases. The dispersed particles (bubbles or drops) are modeled individually using a large representative number of particles, each with their own Lagrangian description. The continuous phases (liquid or gas) use an Eulerian description.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 10166730
• Report Number(s): EGG-M--92026; CONF-921110--10; ON: DE92017850
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303
42 ENGINEERING
420400
BUBBLES
D CODES
DROPLETS
DYNAMICS
ENERGY EFFICIENCY
ENERGY TRANSFER
EQUIPMENT AND PROCESSES
HEAT EXCHANGERS
HEAT TRANSFER
HEAT TRANSFER AND FLUID FLOW
MATHEMATICAL MODELS
NAVIER-STOKES EQUATIONS
NUMERICAL SOLUTION
TURBULENCE
TWO-PHASE FLOW
VOID FRACTION