From 7dfcc480ba1e19bd3232349fc733caef94034292 Mon Sep 17 00:00:00 2001
From: stainer_t <thomas.stainer@oecd-nea.org>
Date: Mon, 8 Sep 2025 13:48:49 +0200
Subject: Initial commit from Polytechnique Montreal

---
 Donjon/src/THMVGJ.f90 | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 Donjon/src/THMVGJ.f90

(limited to 'Donjon/src/THMVGJ.f90')

diff --git a/Donjon/src/THMVGJ.f90 b/Donjon/src/THMVGJ.f90
new file mode 100644
index 0000000..7fdae19
--- /dev/null
+++ b/Donjon/src/THMVGJ.f90
@@ -0,0 +1,111 @@
+SUBROUTINE THMVGJ(VCOOL, DCOOL, PCOOL, MUT, XFL, HD, RHOG, RHOL, EPS, IDFM, VGJ, C0)
+!
+!-----------------------------------------------------------------------
+!
+!Purpose:
+! Update the concentration parameter CO and the drift velocity VGJ 
+! in the THM model after several correlations to implement the drift flux model 
+! in the THM code
+!
+!Copyright:
+! Copyright (C) 2025 Ecole Polytechnique de Montreal
+!
+!Author(s): M. Bellier
+! 04/2025: M. Bellier - Creation
+!
+!Parameters: input
+! XFL     quality of the fluid in the channel
+! DCOOL   density of the fluid in the channel
+! VCOOL   velocity of the fluid in the channel
+! PCOOL   pressure of the fluid in the channel
+! TCOOL   temperature of the fluid in the channel
+! MUT     dynamic viscosity of the fluid in the channel
+! HD      hydraulic diameter of the channel
+! RHOG    density of the vapour in given thermohydraulic conditions
+! RHOL    density of the liquid in given thermohydraulic conditions
+! ESP     void fraction of the fluid
+! IDFM    flag indicating if the drift flux model is to be used 
+!         (0=HEM1(no drift velocity)/1=EPRI/2=MODEBSTION/3=GERAMP/4=CHEXAL) 
+!
+!Parameters: output
+! VGJ     drift velocity
+! C0      concentration parameter
+!
+!-----------------------------------------------------------------------
+!
+    USE GANLIB
+    IMPLICIT NONE
+!----
+!   SUBROUTINE ARGUMENTS
+!----
+    REAL VCOOL, DCOOL, PCOOL, MUT, XFL, HD 
+    REAL EPS, RHOG, RHOL
+    INTEGER IDFM
+!----
+!   LOCAL VARIABLES
+!----
+    REAL g
+    REAL C1, k1, k0, r, PR, SIGM, VGJ, C0, REY
+    INTEGER PC
+
+    REY = ABS(VCOOL*DCOOL) * (1.0 - XFL) * HD / MUT !Reynolds
+    g =  9.81 !gravity
+    PR=PCOOL/10**6 ! PCOOL ou autre valeur de P ? initialement Pinlet
+    SIGM=-7.2391E-6*PR**3+2.8345E-4*PR**2-5.1566E-3*PR+4.2324E-2
+!----
+!   VGJ AND C0 CALCULATION
+!----
+IF (RHOG.EQ.0) THEN
+    C0=0
+    VGJ=0
+ELSE IF (RHOL.EQ.0) THEN
+    C0=0
+    VGJ=0
+
+ELSE IF (IDFM.EQ.0) THEN
+!HEM1 correlation (no drift velocity)
+    VGJ = 0
+    C0 = 1
+    
+ELSE IF (IDFM.EQ.4) THEN
+! Chexal correlation
+! Correlation used in previous codes, after the work of Sarra Zoghlami for CANDU reactors
+    C0=1.13
+    VGJ=1.18*((SIGM*9.81*(RHOL-RHOG))/(RHOL**2))**0.25
+    
+
+ELSE IF (IDFM.EQ.3) THEN
+! GEramp correlation 
+    IF (SIGM.EQ.0) THEN
+        VGJ = 0
+    ELSE 
+        VGJ = (g*SIGM*(RHOL-RHOG)/(RHOG**2))**0.25  
+        IF (EPS.GT.0.65) THEN
+            VGJ= VGJ*(2.9/0.35)*(1-EPS) 
+            C0= 1 + (0.1/0.35)*(1-EPS)
+        ELSE
+            VGJ = 2.9*VGJ
+            C0= 1.1 
+        ENDIF
+    ENDIF
+
+ELSE IF (IDFM.EQ.1) THEN
+! EPRI correlation
+    VGJ= ((2**0.5)*g*SIGM*(RHOL-RHOG)/(RHOL**2))**0.25 * ((1+EPS)**1.5)
+    PC = 22060000
+    C1 = (4 * (PC**2))/(PCOOL*(PC - PCOOL))
+    k1 = MIN(0.8, 1/(1 + exp(-REY /60000)))
+    k0 = k1 + (1-k1) * (RHOG / RHOL)**2
+    r = (1+1.57*(RHOG/RHOL))/(1-k1)
+    IF (EPS.GT.0) THEN
+        C0 = (k0 + (1 - k0)*(EPS**r)*exp((-1)*C1*(1-EPS))*(sinh(C1/2)/sinh(C1/2*EPS)))**(-1)
+    ENDIF
+
+ELSE IF (IDFM.EQ.2) THEN
+! Modfified Bestion Correlation
+    VGJ =  0.188 * (((RHOL - RHOG) * g * HD ) / RHOG )*0.5
+    C0 = 1.2 - 0.2*(RHOG/RHOL)**0.5
+
+ENDIF
+RETURN
+END
\ No newline at end of file
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