RVP fix

Author: EvenSol

src/main/java/neqsim/standards/oilQuality/Standard_ASTM_D6377.java

@@ -48,6 +48,31 @@ public void calculate() {
       logger.error(ex.getMessage(), ex);
     }
 
+    TVP = this.thermoSystem.getPressure();
+
+    this.thermoSystem.setPressure(TVP * 0.9);
+    try {
+      // ASTM D323 -08 method is used for this property calculation. It is defined at the pressure
+      // at 100°F (37.8°C) at which 80% of the stream by volume is vapor at 100°F. In
+      this.thermoOps.TVfractionFlash(0.8);
+    } catch (Exception ex) {
+      logger.error(ex.getMessage(), ex);
+    }
+
+    RVP = this.thermoSystem.getPressure();
+  }
+
+  // old method for RVP
+  public void calculate2() {
+    this.thermoSystem.setTemperature(referenceTemperature, "C");
+    this.thermoSystem.setPressure(ThermodynamicConstantsInterface.referencePressure);
+    this.thermoOps = new ThermodynamicOperations(thermoSystem);
+    try {
+      this.thermoOps.bubblePointPressureFlash(false);
+    } catch (Exception ex) {
+      logger.error(ex.getMessage(), ex);
+    }
+
     TVP = this.thermoSystem.getPressure();
     double liquidVolume = thermoSystem.getVolume();
 

src/main/java/neqsim/thermodynamicOperations/ThermodynamicOperations.java

@@ -576,6 +576,18 @@ public void TVflash(double Vspec) {
     getOperation().run();
   }
 
+  /**
+   * <p>
+   * TVfractionFlash.
+   * </p>
+   *
+   * @param Vspec a double volume fraction of first/lightest phase
+   */
+  public void TVfractionFlash(double Vspec) {
+    operation = new neqsim.thermodynamicOperations.flashOps.TVfractionFlash(system, Vspec);
+    getOperation().run();
+  }
+
   /**
    * <p>
    * PVrefluxFlash.

src/main/java/neqsim/thermodynamicOperations/flashOps/TVfractionFlash.java

@@ -0,0 +1,131 @@
+/*
+ * TVflash.java
+ *
+ * Created on 8. mars 2001, 10:56
+ */
+
+package neqsim.thermodynamicOperations.flashOps;
+
+import neqsim.thermo.system.SystemInterface;
+
+/**
+ * <p>
+ * TVflash class.
+ * </p>
+ *
+ * @author even solbraa
+ * @version $Id: $Id
+ */
+public class TVfractionFlash extends Flash {
+  private static final long serialVersionUID = 1000;
+
+  double Vfractionspec = 0;
+  Flash tpFlash;
+
+  /**
+   * <p>
+   * Constructor for TVflash.
+   * </p>
+   *
+   * @param system a {@link neqsim.thermo.system.SystemInterface} object
+   * @param Vfractionspec a double
+   */
+  public TVfractionFlash(SystemInterface system, double Vfractionspec) {
+    this.system = system;
+    this.tpFlash = new TPflash(system);
+    this.Vfractionspec = Vfractionspec;
+  }
+
+  /**
+   * <p>
+   * calcdQdVP.
+   * </p>
+   *
+   * @return a double
+   */
+  public double calcdQdVdP() {
+    double dQdVP = 0.0;
+    dQdVP = 1.0 / system.getPhase(i).getdPdVTn() / system.getVolume();
+    return dQdVP;
+  }
+
+  /**
+   * <p>
+   * calcdQdV.
+   * </p>
+   *
+   * @return a double
+   */
+  public double calcdQdV() {
+    double dQ = system.getPhase(0).getVolume() / system.getVolume() - Vfractionspec;
+    return dQ;
+  }
+
+  /**
+   * <p>
+   * solveQ.
+   * </p>
+   *
+   * @return a double
+   */
+  public double solveQ() {
+    double oldPres = system.getPressure();
+    double nyPres = system.getPressure();
+    double iterations = 1;
+    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;
+
+      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();
+      // 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);
+    return nyPres;
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public void run() {
+    tpFlash.run();
+    // System.out.println("enthalpy: " + system.getEnthalpy());
+    solveQ();
+
+    // System.out.println("volume: " + system.getVolume());
+    // System.out.println("Temperature: " + system.getTemperature());
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public org.jfree.chart.JFreeChart getJFreeChart(String name) {
+    return null;
+  }
+}

src/test/java/neqsim/standards/oilQuality/Standard_ASTM_D6377Test.java

@@ -19,7 +19,7 @@ void testCalculate() {
     Standard_ASTM_D6377 standard = new Standard_ASTM_D6377(testSystem);
     standard.setReferenceTemperature(37.8, "C");
     standard.calculate();
-    Assertions.assertEquals(0.94552559993, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(1.10455465, standard.getValue("RVP", "bara"), 1e-3);
     Assertions.assertEquals(1.666298367, standard.getValue("TVP", "bara"), 1e-3);
   }
 
@@ -38,7 +38,7 @@ void testCalculate2() {
     Standard_ASTM_D6377 standard = new Standard_ASTM_D6377(testSystem);
     standard.setReferenceTemperature(37.8, "C");
     standard.calculate();
-    Assertions.assertEquals(3.017010, standard.getValue("RVP", "bara"), 1e-3);
+    Assertions.assertEquals(3.604002003478, standard.getValue("RVP", "bara"), 1e-3);
     Assertions.assertEquals(7.8448385024, standard.getValue("TVP", "bara"), 1e-3);
   }
 }