Changeset 146 for branches/newlanguage/eml/heat_exchangers

Timestamp:

Jan 30, 2007, 7:42:28 PM (16 years ago)

Author:

gerson bicca

Message:

testing with switcher in heat exchangers model

Location:

branches/newlanguage/eml/heat_exchangers

Files:

• HEX_Engine.mso (modified) (1 diff)
• HeatExchangerSimplified.mso (modified) (4 diffs)

branches/newlanguage/eml/heat_exchangers/HEX_Engine.mso

@@ -86 +86 @@
 VARIABLES
 # Must be streamPH
-Hot     as streamPH (Brief="Outlet Hot Stream");
-Cold    as streamPH (Brief="Outlet Cold Stream");
+Hot     as vapour_stream (Brief="Outlet Hot Stream");
+Cold    as liquid_stream (Brief="Outlet Cold Stream");
 
 end

branches/newlanguage/eml/heat_exchangers/HeatExchangerSimplified.mso

@@ -477 +477 @@
         Info            =
         "write some information";
-        
-EQUATIONS
+
+PARAMETERS
+
+LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann");
+
+VARIABLES
+
+R               as positive;
+P               as positive;
+Rho     as positive;
+Phi    as positive;
+
+EQUATIONS
+
+"Capacity Ratio for LMTD Correction Fator"
+        R*(Outlet.Cold.T - Inlet.Cold.T ) = (Inlet.Hot.T-Outlet.Hot.T);
+
+"Non - Dimensional Variable for LMTD Correction Fator"
+        P*(Inlet.Hot.T- Inlet.Cold.T)= (Outlet.Cold.T-Inlet.Cold.T);
+
 "Temperature Difference at Inlet"
         DT0 = Inlet.Hot.T - Outlet.Cold.T;
@@ -484 +502 @@
 "Temperature Difference at Outlet"
         DTL = Outlet.Hot.T - Inlet.Cold.T;
-        
-"LMTD Correction Factor"
-        Fc = HE.EshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
+
+"Rho: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
+        Rho*(1-P*R) = (1-P);
+
+"Phi: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
+        Phi  = (sqrt(((Inlet.Hot.T- Outlet.Hot.T)*(Inlet.Hot.T- Outlet.Hot.T))+((Outlet.Cold.T - Inlet.Cold.T)*(Outlet.Cold.T - Inlet.Cold.T))))/(2*((Inlet.Hot.T+ Outlet.Hot.T)-(Inlet.Cold.T+ Outlet.Cold.T)));
+
+switch LMTDcorrection
+        
+        case "Bowmann":
+
+ if R equal 1
+        
+    then
+        Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214))));
+
+        else
+        Fc = sqrt(R*R+1)*ln(abs((1-P*R)/(1-P)))/((1-R)*ln( abs( ( 2-P*(R+1-sqrt(R*R+1)))/ ( 2-P*(R + 1 + sqrt(R*R+1))))));
+
+end
+
+case "Fakeri":
+
+if Rho equal 1
+        
+        then
+        Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi))));
+
+        else
+        Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1));
+        
+end
+
+end
 
 end
@@ -498 +547 @@
         "write some information";
         
-EQUATIONS
+PARAMETERS
+
+LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann");
+
+VARIABLES
+
+R               as positive;
+P               as positive;
+Pc              as positive;
+Rho     as positive;
+#Phi    as positive;
+
+EQUATIONS
+
+"Rho: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
+        Rho*(1-P*R) = (1-P);
+
+"Capacity Ratio for LMTD Correction Fator"
+        R*(Outlet.Cold.T - Inlet.Cold.T ) = (Inlet.Hot.T-Outlet.Hot.T);
+
+"Non - Dimensional Variable for LMTD Correction Fator"
+        P*(Inlet.Hot.T- Inlet.Cold.T)= (Outlet.Cold.T-Inlet.Cold.T);
+        
 "Temperature Difference at Inlet"
         DT0 = Inlet.Hot.T - Outlet.Cold.T;
@@ -505 +576 @@
         DTL = Outlet.Hot.T - Inlet.Cold.T;
         
-"LMTD Correction Factor"
-        Fc = HE.FshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
+if R equal 1
+        
+        then
+        Pc*(2-P)= P;
+        
+        Fc= (sqrt(2)*Pc)/((1-Pc)*ln( abs( ( 2-Pc*0.585786)/( 2-Pc*3.414214))));
+        
+        else 
+        Pc = (sqrt(abs(( 1-P*R)/(1-P)))-1)/(sqrt(abs(( 1-P*R)/(1-P)))-R);
+        Fc =sqrt(R*R+1)*ln(abs((1-Pc*R)/(1-Pc)))/((1-R)*ln( abs( ( 2-Pc*(R+1-sqrt(R*R+1)))/ ( 2-Pc*(R + 1 + sqrt(R*R+1))))));
+        
+end
+
 
 end