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NESC0395 FLAC

FLAC FLAC-SI, Steady-State Flow and Pressure Distribution, 1-D Incompressible Flow Equation

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1. NAME OR DESIGNATION OF PROGRAM:  FLAC
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2. COMPUTERS
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Program name Package id Status Status date
FLAC NESC0395/01 Tested 01-OCT-1973

Machines used:

Package ID Orig. computer Test computer
NESC0395/01 IBM 370 series IBM 370 series
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3. DESCRIPTION OF PROBLEM OR FUNCTION

The flow analysis code FLAC calculates the steady-state flow and pressure distribution in an arbitrary network. The program includes the possibility of heat addition and mass addition in any portion of the network.
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4. METHOD OF SOLUTION

The equations that are solved are the one- dimensional momentum equation for incompressible flow in a duct and  the conservation equations for flow and energy at each node. Density changes due to heat addition are included according to the perfect gas law. The method for solving the set of algebraic equations is a  variation of the point relaxation technique.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The FLAC program does not consider two-phase flow or open-channel flow, as in hydraulics.
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6. TYPICAL RUNNING TIME

Approximately 30 seconds are required for a problem consisting of 100 branches. NESC executed the sample problem in 20 seconds on an IBM370/195.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
NESC0395/01 01-OCT-1973 Tested at NEADB
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10. REFERENCE:
NESC0395/01, included references:
- G.J.  Malek:
  Development of the Flow Analysis Code FLAC
  GA-9482 (June 1969).
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11. MACHINE REQUIREMENTS

The computer storage requirements for FLAC are flexible, and the size of the various arrays can be adjusted to  suit any problem. With all arrays set to their maximum, a problem consisting of 1500 branches and 700 nodes requires approximately 50,000 storage locations on the UNIVAC1108. 180K bytes of memory are needed for the IBM370 version.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0395/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  EXEC2
(UNIVAC1108), OS/370 (IBM370).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   For
large problems, auxiliary data tapes can be used to store input information and results from the last iteration. These data tapes can be used to restart the problem in case of nonconvergence. The General Atomic system routine WARN permits the user to prescribe at  run time a time interval parameter which is used as a warning period prior to job termination on the elapsed time job limit. Use of the statement CALL WARN (IWARN) returns a negative value of IWARN until  the job enters the specified warning time interval after which a positive value is assigned. This routine is used to initiate writing to tape of restart data for subsequent runs. In the IBM version, subroutine WARN counts the number of iterations taken. If convergence is not achieved in IMAX iterations, the job terminates.  The value assigned IMAX currently is 1000.
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15. NAME AND ESTABLISHMENT OF AUTHORS

   1108          G. J. Malek
                 General Atomic Company
                 P. O. Box 81608
                 San Diego, California  92138
   370           R. G. Olson
                 Detroit Edison
                 2000 Second Avenue
                 Detroit, Michigan  48226
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16. MATERIAL AVAILABLE
NESC0395/01
File name File description Records
NESC0395_01.001 SOURCE PROGRAM (FORTRAN) 746
NESC0395_01.002 JCL+SAMPLE PROBLEM 94
NESC0395_01.003 OUTPUT LIST OF SAMPLE PROBLEM 800
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17. CATEGORIES
  • H. Heat Transfer and Fluid Flow

Keywords: HTGR reactors, fluid flow, gases, heat transfer, pressure, temperature distribution.