NESC0727 K-FIX

1. NAME OR DESIGNATION OF PROGRAM:  K-FIX

3. DESCRIPTION OF PROBLEM OR FUNCTION

The transient dynamics of two-  dimensional, two-phase flow with interfacial exchange are calculated at all flow speeds. Each phase is described in terms of its own density, velocity, and temperature. Separate sets of field equations govern the gas and liquid phase dynamics. The six field equations for the two phases couple through mass, momentum, and energy exchange.

4. METHOD OF SOLUTION

The equations are solved using an Eulerian finite difference technique that implicitly couples the rates of phase transitions, momentum, and energy exchange to determination of the pressure, density, and velocity fields. The implicit solution is accomplished iteratively using a point relaxation technique without linearizing the equations, thus eliminating the need for numerous derivative terms. Solutions can be obtained in one and two  space dimensions in plane geometry and in cylindrical geometry with  axial symmetry and zero azimuthal velocity. Solutions in shperical geometry can also be obtained in one space dimension. The geometric  region of interest is divided into many finite-sized, space-fixed zones called cells which form the computing mesh. In plane geometry  the cells are rectangular cylinders, in cylindrical geometry they are toroids with rectangular cross section, and in spherical geometry they are spherical shells.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:

6. TYPICAL RUNNING TIME

The sample problem took less than 14 CP seconds to compile and less than 62 CP seconds to calculate all variables for 140 time cycles on a CDC CYBER170/875.

7. UNUSUAL FEATURES OF THE PROGRAM

K-FIX  is  written in  a  highly
modular form to be easily adaptable to a variety of problems.

8. RELATED AND AUXILIARY PROGRAMS

K-FIX uses the implicit multifield  technique developed for the KACHINA program. K-FIX differs from KACHINA in that it implicitly couples phase transitions and interfacial heat transfer to the fluid dynamics in the pressure iteration. K-FIX(3D) (NESC 877) is an extension of K-FIX to three dimensions.

10. REFERENCES

- J.R. Travis and W.C. Rivard
  PRESBC: Pressure Boundary Conditions for the K-FIX Code,
  NUREG/CR-1536 (LA-NUREG-6623, Suppl. III), July 1980.
- K-FIX, NESC No. 727.7600B, K-FIX Tape Description and Recommended
  Modifications for Pressure Boundary Conditions,
  National Energy Software Center Note 88-81, June 30, 1988.

- W.C. Rivard, M.D. Torrey:
  K-FIX: A Computer Program for Transient, Two-Dimensional,
  Two-Fluid Flow
  LA-NUREG-6623, NRC-4 (April 1977)
- W.C. Rivard and M.D. Torrey:
  PERM: Corrections to the K-FIX Code
  LA-NUREG-6623 Suppl., NRC-4 (March 1978)
- FORTRAN Functions and System Subroutines in K-FIX,
  LANL Note (May 1977)

11. MACHINE REQUIREMENTS

The sample problem, excluding plotting routines, required 55,000 (octal) words of memory on a CDC CYBER170/875.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE (CDC7600),  NOS 2.4 (CDC CYBER170).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

K-FIX makes use of the CDC7600 UPDATE program for variable dimensioning and for code modification for different model applications. These system-dependent features, together with the program's use of environment-dependent plotting routines and job card timing information, will require use of suitable replacement routines and extra programming effort for implementation of K-FIX at other installations or on different machines. The sample problem output included with the package was created by executing K-FIX on a CDC CYBER170/875. The output may differ slightly when executed on other  systems.

15. NAME AND ESTABLISHMENT OF AUTHORS

                 W. C. Rivard and M. D. Torrey
                 Los Alamos Scientific Laboratory
                 P. O. Box 1663
                 Los Alamos, New Mexico  87545

File name	File description	Records
NESC0727_01.001	INFORMATION	4
NESC0727_01.002	JCL	32
NESC0727_01.003	OUTPUT OF S.P.	6090
NESC0727_01.004	SOURCE	2658
NESC0727_01.005	SOURCE	195
NESC0727_01.006	INPUT FOR S.P.	18
NESC0727_01.007	AUXILIARY PROGRAM SOURCE	240
NESC0727_01.008	AUXILIARY PROGRAM SOURCE	240