NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHOR, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
---|---|---|---|

SOLA-LOOP | NESC0859/02 | Tested | 28-OCT-1991 |

SOLA-LOOP | NESC0859/03 | Tested | 03-MAR-1999 |

Machines used:

Package ID | Orig. computer | Test computer |
---|---|---|

NESC0859/02 | CONVEX C 120 | DEC VAX 8810 |

NESC0859/03 | IBM PC | PC Pentium II 400 |

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3. DESCRIPTION OF PROBLEM OR FUNCTION

SOLA-LOOP is designed for the solution of transient two-phase flow in networks composed of one- dimensional components. The fluid dynamics is described by a non- equilibrium drift-flux formulation of the fluid conservation laws.

Although developed for nuclear reactor safety analysis, SOLA-LOOP may be used as the basis of other types of special-purpose network codes. The program can accommodate almost any set of constitutive relations, property tables, or other special features required for different applications.

SOLA-LOOP is designed for the solution of transient two-phase flow in networks composed of one- dimensional components. The fluid dynamics is described by a non- equilibrium drift-flux formulation of the fluid conservation laws.

Although developed for nuclear reactor safety analysis, SOLA-LOOP may be used as the basis of other types of special-purpose network codes. The program can accommodate almost any set of constitutive relations, property tables, or other special features required for different applications.

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4. METHOD OF SOLUTION

The drift-flux equations are formulated as continuity equations, the momentum equation, and the internal energy equation. The mixture density, the macroscopic vapor density, the center of mass velocity, and the mixture specific internal energy are chosen as dependent variables, and time and axial position are the independent variables. Constitutive relations and exchange rates are determined by the intended use of the code. The calculation cycle used to solve by point relaxation methods the finite difference formulation of the flow equations in a single one- dimensional component is made up of four tasks. First, the momentum equation is advanced explicitly using the values from the previous cycle for all contributions. Next, an iteration is made to replace the pressure with advanced time values. This pressure iteration scheme is a variant of the implicit continuous fluid Eulerian (ICE) technique.

Then, all other dependent variables are updated, and in the fourth task data output, time-step control, and housekeeping operations are performed. Various boundary conditions may be applied at the ends of the one-dimensional component meshes to represent inlet and exit conditions including prescribed velocities or pressures, uniform or gradient-free outflow, and periodic boundaries in which the bottom and top of a component are joined. Where two or more components are coupled, special coupling equations are solved to obtain the appropriate boundary conditions for each. Different time-steps can be used in various components. The time-steps are determined by numerical stability requirements and other user-supplied conditions.

The drift-flux equations are formulated as continuity equations, the momentum equation, and the internal energy equation. The mixture density, the macroscopic vapor density, the center of mass velocity, and the mixture specific internal energy are chosen as dependent variables, and time and axial position are the independent variables. Constitutive relations and exchange rates are determined by the intended use of the code. The calculation cycle used to solve by point relaxation methods the finite difference formulation of the flow equations in a single one- dimensional component is made up of four tasks. First, the momentum equation is advanced explicitly using the values from the previous cycle for all contributions. Next, an iteration is made to replace the pressure with advanced time values. This pressure iteration scheme is a variant of the implicit continuous fluid Eulerian (ICE) technique.

Then, all other dependent variables are updated, and in the fourth task data output, time-step control, and housekeeping operations are performed. Various boundary conditions may be applied at the ends of the one-dimensional component meshes to represent inlet and exit conditions including prescribed velocities or pressures, uniform or gradient-free outflow, and periodic boundaries in which the bottom and top of a component are joined. Where two or more components are coupled, special coupling equations are solved to obtain the appropriate boundary conditions for each. Different time-steps can be used in various components. The time-steps are determined by numerical stability requirements and other user-supplied conditions.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Conservation of momentum is not required by the finite difference approximations used for the momentum equation. Current dimensioning in the SOLA- LOOP program allows maxima of

10 components

8 segments per component

200 junctions

6 time levels, pressure groups, and vapor production rates per cell

5 boundary data sets.

These restrictions may be adjusted by changing the values of the variables NP, NS, NJ, NK, and NM, respectively, and all appropriate DIMENSION statements.

Conservation of momentum is not required by the finite difference approximations used for the momentum equation. Current dimensioning in the SOLA- LOOP program allows maxima of

10 components

8 segments per component

200 junctions

6 time levels, pressure groups, and vapor production rates per cell

5 boundary data sets.

These restrictions may be adjusted by changing the values of the variables NP, NS, NJ, NK, and NM, respectively, and all appropriate DIMENSION statements.

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7. UNUSUAL FEATURES OF THE PROGRAM

Network systems often contain low- speed flow with slowly-varying properties in one region and high- speed flow or flow that requires a finely-detailed description in another. The variable time-steps and subcycling provisions in SOLA- LOOP are designed specifically for such systems.

Network systems often contain low- speed flow with slowly-varying properties in one region and high- speed flow or flow that requires a finely-detailed description in another. The variable time-steps and subcycling provisions in SOLA- LOOP are designed specifically for such systems.

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8. RELATED AND AUXILIARY PROGRAMS

The solution algorithm has evolved from earlier SOLA series programs. The original SOLA was designed for problems involving a single incompressible fluid in a fixed- region. SOLA-LOOP is an advanced network code derived from the SOLA- DF (NESC Abstract 832) code, which is based on a drift-flux approximation for the dynamics of a two-phase mixture.

K-FIX (NESC Abstract 727) and K-TIF (NESC Abstract 876) are detailed models for transient, two-phase flows in two and three dimensions.

The solution algorithm has evolved from earlier SOLA series programs. The original SOLA was designed for problems involving a single incompressible fluid in a fixed- region. SOLA-LOOP is an advanced network code derived from the SOLA- DF (NESC Abstract 832) code, which is based on a drift-flux approximation for the dynamics of a two-phase mixture.

K-FIX (NESC Abstract 727) and K-TIF (NESC Abstract 876) are detailed models for transient, two-phase flows in two and three dimensions.

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Package ID | Status date | Status |
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NESC0859/02 | 28-OCT-1991 | Screened |

NESC0859/03 | 03-MAR-1999 | Tested at NEADB |

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10. REFERENCES

- C.W. Hirt, N.C. Romero, M.D. Torrey, and J.R. Travis:

SOLA-DF: A Solution Algorithm for Nonequilibrium Two-Phase Flow

NUREG/CR-0690 (LA-7725/MS), June 1979.

- C.W. Hirt, B.D. Nichols, and N.C. Romero:

SOLA - A Numerical Solution Algorithm for Transient Fluid Flow

LA-5852, April 1975.

- C.W. Hirt, N.C. Romero, M.D. Torrey, and J.R. Travis:

SOLA-DF: A Solution Algorithm for Nonequilibrium Two-Phase Flow

NUREG/CR-0690 (LA-7725/MS), June 1979.

- C.W. Hirt, B.D. Nichols, and N.C. Romero:

SOLA - A Numerical Solution Algorithm for Transient Fluid Flow

LA-5852, April 1975.

NESC0859/02, included references:

- C.W. Hirt, T.A. Oliphant, W.C. Rivard, N.C. Romero, M.D. Torrey:SOLA-LOOP, A Nonequilibrium Drift-Flux Cpde for Two-Phase Flow in

Networks

NUREG/CR-0626 LA-7659 R-4 (June 1979).

NESC0859/03, included references:

- C.W. Hirt, T.A. Oliphant, W.C. Rivard, N.C. Romero, M.D. Torrey:SOLA-LOOP, A Nonequilibrium Drift-Flux Cpde for Two-Phase Flow in

Networks

NUREG/CR-0626 LA-7659 R-4 (June 1979).

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Package ID | Computer language |
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NESC0859/02 | FORTRAN-IV |

NESC0859/03 | FORTRAN-77 |

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15. NAME AND ESTABLISHMENT OF AUTHOR

C.W. Hirt, T.A. Oliphant, W.C. Rivard, N.C. Romero, and M.D. Torrey* Los Alamos National Laboratory

P. O. Box 1663

Los Alamos, New Mexico 87545, U.S.A.

* Contact

C.W. Hirt, T.A. Oliphant, W.C. Rivard, N.C. Romero, and M.D. Torrey* Los Alamos National Laboratory

P. O. Box 1663

Los Alamos, New Mexico 87545, U.S.A.

* Contact

NESC0859/03

Centro Atomico Bariloche8400 BARILOCHE

ARGENTINA

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NESC0859/03

Solaloop.for Source codeSolaloop.ar Input file

NESC0859/02

File name | File description | Records |
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NESC0859_02.001 | Information file | 32 |

NESC0859_02.002 | SOLA-LOOP source program (FORTRAN) | 4044 |

NESC0859_02.003 | SOLA-LOOP test case input data | 22 |

NESC0859_02.004 | SOLA-LOOP test case printed output | 1052 |

Keywords: finite difference method, fluid flow, ice method, network analysis, phase transformations, two-dimensional, two-phase flow.