A PRESSURE REGULATOR OPTION FOR THE GENERALIZED FLUID SYSTEM SIMULATION PROGRAM (GFSSP): A PRESSURE REGULATOR OPTION FOR THE GENERALIZED FLUID SYSTEM SIMULATION PROGRAM (GFSSP) Paul Schallhorn
Sverdrup Technology, Inc.
GFSSP User’s Group Meeting
November 16, 2000
Task 560-6100-0500-01
OUTLINE: OUTLINE Objective
Approach
Results
Summary
OBJECTIVE: OBJECTIVE Objective:
To add a pressure regulator capability to the Generalized Fluid System Simulation Program (GFSSP) Version 3.0, via the User Subroutines.
APPROACH: APPROACH A pressure regulator is a device that will maintain a set downstream pressure provided that the upstream pressure is larger than the set point.
In order to maintain pressure, area will vary as a function of time; therefore, the pressure regulator will be applicable to transient models only.
When the upstream pressure is greater than the desired regulated pressure, the area of the regulator will be calculated by means of a derivative of area w.r.t. pressure.
APPROACH (Continued): APPROACH (Continued) When the upstream pressure is less than or equal to the desired regulated pressure, the area will be set to the maximum value for the device.
The area will be calculated using the following formula:
APPROACH (Continued): APPROACH (Continued) The coding for the pressure regulator was performed in the following user subroutines of GFSSP 3.0:
FILENUM (file number assignment user subroutine)
USRSET (user defined input file user subroutine)
BNDUSER (user defined update subroutine called at the
end of each time step)
PRNUSER (user defined output user subroutine)
Pressure regulator branches should be modeled using resistance option -02 (flow through a restriction), with the area specified equal to the maximum allowable area.
Additional information regarding the regulator is provided in a later section of the file.
APPROACH (Continued): APPROACH (Continued) User Develops
Modified GFSSP
Input File For
Pressure Regulator
Model User Initiates a
run of a pressure
regulator (p.r.)
model
(GFSSP3PR.EXE ) Subroutine READIN
calls USRSET if
USETUP=.TRUE.
Specialized input
file includes logical
indicating if p.r. is
present, p.r. version
& p.r. information ITER=0? At the end of each
time step, BNDUSER is
called to calculate an
update p.r. branch area
to maintain downstream
pressure no yes Calculate circuit
conditions at
next time step Supply
Ap.r. new Write results to
main GFSSP
output files; write
pressure regulator
information to a
special file entitled
“PRESREG.OUT” Last Time Step? no yes End
Flow Chart Running GFSSP3PR
APPROACH (Continued): APPROACH (Continued) Modified Input Deck GFSSP VERSION
300
ANALYST
PAS
INPUT DATA FILE NAME
PRTESTA.DAT
OUTPUT FILE NAME
PRTESTA.OUT
TITLE
PRESSURE REGULATOR TEST
USETUP
T
PRESSURE REGULATOR VERSION
100
DENCON GRAVITY ENERGY MIXTURE THRUST STEADY TRANSV SAVER
F F T F F F T F
HEX HCOEF REACTING INERTIA CONDX ADDPROP PRINTI ROTATION
F F F F F F F F
BUOYANCY HRATE INVAL MSORCE MOVBND TPA VARGEO TVM
F T F F F F F F
SHEAR PRNTIN PRNTADD LAMINAR TRANSQ PRESSREG
F F F F F T
PRESS INSUC VARROT
F F F
NORMAL SIMUL SECONDL
F F F
NNODES NINT NBR NF
3 2 2 1
APPROACH (Continued): APPROACH (Continued) Modified Input Deck - Continued RELAXK RELAXD RELAXH CC NITER
1 0.5 1 0.0001 100
DTAU TIMEF TIMEL NPSTEP
0.1 0 200 1
NFLUID(I), I=1,NF
4
NODE INDEX
1 1
2 1
3 2
.
.
.
BRANCH
23
UPSTREAM ANGLE
12 0.0000
DOWNSTREAM ANGLE
NUMBER OF PRESSURE REGULATORS
1
PRESS.REG. BRANCH DESIRED DOWNSTREAM PRESSURE (PSIA)
12 40.0
RESTART NODE INFORMATION FILE
FNODE.DAT
RESTART BRANCH INFORMATION FILE
FBRANCH.DAT
MODEL VALIDATION RESULTS: MODEL VALIDATION RESULTS Three test cases were identified to validate that the pressure regulator option works as desired. These cases are:
1. Tank-Pressure Regulator-Tube, with initial tank
pressure >> regulated pressure (validates maintaining
desired downstream pressure).
2. Tank-Pressure Regulator-Tube, with initial tank
pressure ~ regulated pressure (validates maintaining
maximum area requirement).
3. Tank-2 Pressure Regulators-2 Tubes, with initial tank
pressure > regulated pressures (validates multiple
pressure regulators, each maintaining their own
desired downstream pressure).
PRESSURE REGULATOR VALIDATION - TEST CASE 1: PRESSURE REGULATOR VALIDATION - TEST CASE 1 Physical Situation Model N2 Tank of 10 ft3, initially at 600 psia, 75°F 0.1 inch inner diameter tube, 10 feet long. Pressure Regulator, set for a downstream pressure of 40 psia. 1 3 2 12 23 Pressure Regulator, set for a downstream pressure of 40 psia. 0.1 inch inner diameter tube, 10 feet long. N2 Tank of 10 ft3, initially at 600 psia, 75°F
PRESSURE REGULATOR VALIDATION - TEST CASE 1 RESULTS: PRESSURE REGULATOR VALIDATION - TEST CASE 1 RESULTS
PRESSURE REGULATOR VALIDATION - TEST CASE 2: Physical Situation Model N2 Tank of 10 ft3, initially at 55 psia, 75°F 0.1 inch inner diameter tube, 10 feet long. Pressure Regulator, set for a downstream pressure of 50 psia. 1 3 2 12 23 Pressure Regulator, set for a downstream pressure of 50 psia. 0.1 inch inner diameter tube, 10 feet long. N2 Tank of 10 ft3, initially at 55 psia, 75°F PRESSURE REGULATOR VALIDATION - TEST CASE 2
PRESSURE REGULATOR VALIDATION - TEST CASE 2 RESULTS: PRESSURE REGULATOR VALIDATION - TEST CASE 2 RESULTS
PRESSURE REGULATOR VALIDATION - TEST CASE 3: Physical Situation Model N2 Tank of 10 ft3, initially at 600 psia, 75°F 0.1 inch inner diameter tube, 10 feet long. Pressure Regulator, set for a downstream pressure of 50 psia. 1 4 2 12 24 Pressure Regulator, set for a downstream pressure of 50 psia. 0.1 inch inner diameter tube, 10 feet long. N2 Tank of 10 ft3, initially at 600 psia, 75°F PRESSURE REGULATOR VALIDATION - TEST CASE 3 0.1 inch inner diameter tube, 10 feet long. Pressure Regulator, set for a downstream pressure of 27.5 psia. 3 13 34 0.1 inch inner diameter tube, 10 feet long. Pressure Regulator, set for a downstream pressure of 27.5 psia.
PRESSURE REGULATOR VALIDATION - TEST CASE 3 RESULTS: PRESSURE REGULATOR VALIDATION - TEST CASE 3 RESULTS
SUMMARY: SUMMARY A pressure regulator option has successfully been added to GFSSP 3.0 via User Subroutines.
The option uses a modified version of the GFSSP input file.
Three test cases were identified to validate the capability.
These three test cases have been modeled, and successfully validate the modeling approach.
Based upon this validation, a recommendation to proceed with documentation and release of GFSSP3PR is requested.