Changeset 472 for trunk/eml/heat_exchangers

Timestamp:

Mar 6, 2008, 8:43:11 PM (16 years ago)

Author:

gerson bicca

Message:

Double Pipe: added option to solve convergence problems from a simplified model

File:

• trunk/eml/heat_exchangers/DoublePipe.mso (modified) (6 diffs)

trunk/eml/heat_exchangers/DoublePipe.mso

@@ -47 +47 @@
         OuterTurbulentCorrelation   as Switcher         (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
 
+        CalculationApproach                             as Switcher             (Brief="Options for convergence Calculations ",Valid=["Simplified","Full"],Default="Full");
+        Qestimated                                                              as power                                (Brief="Estimated Duty", Default=70, Lower=1e-6, Upper=1e10);
+        
         Pi                              as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi");
         DoInner         as length                       (Brief="Outside Diameter of Inner Pipe",Lower=1e-6);
@@ -475 +478 @@
         Outer.HeatTransfer.hcoeff= (Outer.HeatTransfer.Nu*Outer.Properties.Average.K/Outer.HeatTransfer.Dh)*Outer.HeatTransfer.Phi;
 
+switch CalculationApproach
+        
+        case "Full":
+        
 "Total Pressure Drop Outer Stream"
-        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric+Outer.PressureDrop.Pd_ret;
+        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
 
 "Total Pressure Drop Inner Stream"
-        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric+Inner.PressureDrop.Pd_ret;
+        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
         
 "Pressure Drop Outer Stream"
@@ -492 +499 @@
 "Inner Pipe Pressure Drop for friction"
         Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(DiInner*Inner.HeatTransfer.Phi);
+
+
+        case "Simplified":
+        
+"Total Pressure Drop Outer Stream"
+        Outer.PressureDrop.Pdrop  = 0*'kPa';
+
+"Total Pressure Drop Inner Stream"
+        Inner.PressureDrop.Pdrop  = 0*'kPa';
+        
+"Pressure Drop Outer Stream"
+        OutletOuter.P  = InletOuter.P;
+
+"Pressure Drop Inner Stream"
+        OutletInner.P  = InletInner.P;
+        
+"Outer Pipe Pressure Drop for friction"
+        Outer.PressureDrop.Pd_fric = 0*'kPa';
+        
+"Inner Pipe Pressure Drop for friction"
+        Inner.PressureDrop.Pd_fric = 0*'kPa';
+
+end
 
 "Outer Pipe Pressure Drop due to return"
@@ -639 +669 @@
         case "outer":
 
+switch CalculationApproach
+        
+        case "Full":
+        
 "Duty"
         Details.Q       = Method.Eft*Method.Cmin*(InletOuter.T-InletInner.T);
 
+        case "Simplified":
+        
+"Duty"
+        Details.Q       = Qestimated;
+
+end
+
 "Hot Stream Heat Capacity"
         Method.Ch  = InletOuter.F*Outer.Properties.Average.Cp;
@@ -652 +693 @@
         case "inner":
 
+switch CalculationApproach
+        
+        case "Full":
+        
 "Duty"
         Details.Q       = Method.Eft*Method.Cmin*(InletInner.T-InletOuter.T);
+
+        case "Simplified":
+
+"Duty"
+        Details.Q       = Qestimated;
+
+end
 
 "Cold Stream Heat Capacity"
@@ -715 +767 @@
 EQUATIONS
 
-"Exchange Surface Area"
+switch CalculationApproach
+        
+        case "Full":
+        
+"Duty"
         Details.Q = Details.Ud*Pi*DoInner*Lpipe*Method.LMTD;
         
+        case "Simplified":
+        
+"Duty"
+        Details.Q = Qestimated;
+
+end
+
 "LMTD Correction Factor - True counter ou cocurrent flow"
         Method.Fc = 1;