update

equinor · Oct 7, 2024 · 2fbb74f · 2fbb74f
1 parent d605927
commit 2fbb74f
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Showing 3 changed files with 49 additions and 28 deletions.
diff --git a/src/main/java/neqsim/thermo/system/SystemThermo.java b/src/main/java/neqsim/thermo/system/SystemThermo.java
@@ -1921,7 +1921,7 @@ public double getdPdVtn() {
     double dPdV = 0.0;
     for (int i = 0; i < numberOfPhases; i++) {
       if (isPhase(i)) {
-        dPdV += getPhase(i).getdPdVTn() * getPhase(i).getVolume() / getVolume();
+        dPdV += getPhase(i).getdPdVTn(); // * getPhase(i).getVolume() / getVolume();
       }
     }
     return dPdV;

diff --git a/src/main/java/neqsim/thermodynamicoperations/flashops/TVfractionFlash.java b/src/main/java/neqsim/thermodynamicoperations/flashops/TVfractionFlash.java
@@ -44,8 +44,8 @@ public TVfractionFlash(SystemInterface system, double Vfractionspec) {
    * @return a double
    */
   public double calcdQdVdP() {
-    double dQdVP = 0.0;
-    dQdVP = 1.0 / system.getPhase(i).getdPdVTn() / system.getVolume();
+    double dQdVP = 1.0 / system.getPhase(0).getdPdVTn() / system.getVolume()
+        + system.getPhase(0).getVolume() / Math.pow(system.getVolume(), 2.0) * system.getdVdPtn();
     return dQdVP;
   }
 
@@ -71,49 +71,46 @@ public double calcdQdV() {
   public double solveQ() {
     double oldPres = system.getPressure();
     double nyPres = system.getPressure();
-    double iterations = 1;
+    int iterations = 0;
     double error = 100.0;
     double numericdQdVdP = 0.0;
     double dQdV = 0.0;
     double olddQdV = 0.0;
     double pressureStep = 1.0;
     do {
       iterations++;
-      oldPres = nyPres;
       system.init(3);
-      double dQDVdP = calcdQdVdP();
-
-      numericdQdVdP = (calcdQdV() - olddQdV) / pressureStep;
+      oldPres = nyPres;
+      double dqdv = calcdQdV();
+      double dqdvdp = calcdQdVdP();
+      nyPres = oldPres - iterations / (iterations + 100.0) * dqdv / dqdvdp;
+      pressureStep = nyPres - oldPres;
 
-      if (iterations < 5) {
-        nyPres = oldPres - 1.0 / 10.0 * calcdQdV() / dQDVdP;
-      } else {
-        nyPres = oldPres - 1.0 * calcdQdV() / numericdQdVdP;
-      }
       if (nyPres <= 0.0) {
         nyPres = oldPres * 0.9;
       }
-      if (nyPres >= oldPres * 2) {
-        nyPres = oldPres * 2.0;
-      }
-      pressureStep = nyPres - oldPres;
-
-      olddQdV = calcdQdV();
       system.setPressure(nyPres);
       tpFlash.run();
-      error = Math.abs(calcdQdV()) / system.getVolume();
+
+      error = Math.abs(dqdv / Vfractionspec);
       // System.out.println("error " + error + "iteration " + iterations + " dQdv " + calcdQdV()
       // + " new pressure " + nyPres + " error " + Math.abs((nyPres - oldPres) / (nyPres))
-      // + " numberofphases " + system.getNumberOfPhases() + " dQDVdP " + dQDVdP + " dQDVdPnumeric"
-      // + numericdQdVdP);
-    } while ((error > 1e-9 && iterations < 200) || iterations < 3);
+      // + " numberofphases " + system.getNumberOfPhases());
+    } while ((error > 1e-6 && Math.abs(pressureStep) > 1e-6 && iterations < 200) || iterations < 6);
     return nyPres;
   }
 
   /** {@inheritDoc} */
   @Override
   public void run() {
     tpFlash.run();
+    if (system.getNumberOfPhases() == 1) {
+      do {
+        system.setPressure(system.getPressure() * 0.9);
+        tpFlash.run();
+      } while (system.getNumberOfPhases() == 1);
+    }
+
     // System.out.println("enthalpy: " + system.getEnthalpy());
     solveQ();
 

diff --git a/src/test/java/neqsim/standards/oilquality/Standard_ASTM_D6377Test.java b/src/test/java/neqsim/standards/oilquality/Standard_ASTM_D6377Test.java
@@ -20,7 +20,7 @@ void testCalculate() {
     Standard_ASTM_D6377 standard = new Standard_ASTM_D6377(testSystem);
     standard.setReferenceTemperature(37.8, "C");
     standard.calculate();
-    Assertions.assertEquals(1.10455465, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(1.10445689545, standard.getValue("RVP", "bara"), 1e-3);
     Assertions.assertEquals(1.666298367, standard.getValue("TVP", "bara"), 1e-3);
   }
 
@@ -40,14 +40,38 @@ void testCalculate2() {
     standard.setMethodRVP("VPCR4");
     standard.setReferenceTemperature(37.8, "C");
     standard.calculate();
-    Assertions.assertEquals(3.6145219653041623, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(3.61452722, standard.getValue("RVP", "bara"), 1e-3);
     Assertions.assertEquals(7.867696779327479, standard.getValue("TVP", "bara"), 1e-3);
 
     standard.setMethodRVP("RVP_ASTM_D6377");
     standard.setReferenceTemperature(37.8, "C");
     standard.calculate();
-    Assertions.assertEquals(3.014511319063671, standard.getValue("RVP", "bara"), 1e-3);
-    Assertions.assertEquals(7.867696779327479
-    , standard.getValue("TVP", "bara"), 1e-3);
+    Assertions.assertEquals(3.01451570813, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(7.867696779327479, standard.getValue("TVP", "bara"), 1e-3);
+  }
+
+  @Test
+  void testCalculate3() {
+    SystemInterface testSystem = new SystemSrkEos(273.15 + 2.0, 1.0);
+    testSystem.addComponent("n-pentane", 0.545);
+    testSystem.addComponent("nC10", 0.545);
+    testSystem.addComponent("nC12", 0.545);
+    testSystem.addTBPfraction("C11", 0.545, 145.0 / 1000.0, 0.82);
+    testSystem.setMixingRule(2);
+    testSystem.setMultiPhaseCheck(true);
+    testSystem.init(0);
+    testSystem.setPressure(100.0);
+    Standard_ASTM_D6377 standard = new Standard_ASTM_D6377(testSystem);
+    standard.setMethodRVP("VPCR4");
+    standard.setReferenceTemperature(37.8, "C");
+    standard.calculate();
+    Assertions.assertEquals(0.25505060, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(0.261765909821, standard.getValue("TVP", "bara"), 1e-3);
+
+    standard.setMethodRVP("RVP_ASTM_D6377");
+    standard.setReferenceTemperature(37.8, "C");
+    standard.calculate();
+    Assertions.assertEquals(0.2127122042, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(0.2617659098, standard.getValue("TVP", "bara"), 1e-3);
   }
 }