Changeset 131 for branches/newlanguage/eml

Timestamp:

Jan 24, 2007, 11:39:47 AM (16 years ago)

Author:

gerson bicca

Message:

updated

File:

• branches/newlanguage/eml/heat_exchangers/Mheatex.mso (modified) (6 diffs)

branches/newlanguage/eml/heat_exchangers/Mheatex.mso

@@ -18 +18 @@
 *
 *       Streams:
-*               * Inlet(Ninlet) streams ....    at least one material stream
-*               * Outlet stream             ....        one material stream
+*               * Hot Inlet streams ....        at least one Hot material stream
+*               * Cold Inlet streams ....       at least one Cold material stream
+*               * Hot Outlet streams  ....      one material stream for each Hot Inlet
+*               * Cold Outlet streams  ....     one material stream for each Cold Inlet
 *
 *       Purpose:
-*               * Determines thermal and phase conditions of outlet stream
+*               * Heat Transfer between multiple hot and cold streams.
 *
 *----------------------------------------------------------------------
@@ -58 +60 @@
 VARIABLES
 
-        Hot  (Nhot)     as stream_therm;# Outlet Hot Streams
-        Cold (Ncold)    as stream_therm;# Outlet Cold Streams
+        Hot  (Nhot)     as liquid_stream;# Outlet Hot Streams
+        Cold (Ncold)    as liquid_stream;# Outlet Cold Streams
         
 end
@@ -69 +71 @@
 PARAMETERS
 
-ext PP          as CalcObject   (Brief="Physical Properties");
-ext     NComp   as Integer              (Brief="Number of Components"); 
-        HE              as CalcObject   (Brief="Cold Box Calculations",File="heatex");
+outer PP                as Plugin       (Brief="Physical Properties");
+outer   NComp   as Integer              (Brief="Number of Components"); 
+#       HE              as Plugin       (Brief="Cold Box Calculations",File="heatex");
         Side    as Integer              (Brief="Flow Direction",Lower=0,Upper=1);
         Ncold   as Integer              (Brief="Number of Inlet Cold Streams",Lower=1);
@@ -84 +86 @@
         LMTD    as temp_delta   (Brief="Logarithmic Mean Temperature Difference");
         UA      as positive     (Unit="W/K");
-
+        DT0     as temp_delta   (Brief="Temperature Difference at Inlet",Lower=1);
+        DTL             as temp_delta   (Brief="Temperature Difference at Outlet",Lower=1);
+        
 SET
 
 # Flow Direction
-        Side = HE.FlowDir();
+#       Side = HE.FlowDir();
 
 # Inlet Ncold Parameters
@@ -116 +120 @@
         Outlet.Cold.z = Inlet.Cold.z;
         
+
+
+for i in [1:Nhot]
+
 "Vapourisation Fraction Hot Stream"
-        Outlet.Hot.v = Inlet.Hot.v;             
+        Outlet.Hot(i).v = PP.VapourFraction(Outlet.Hot(i).T,Outlet.Hot(i).P,Outlet.Hot(i).z);           
+        
+end     
+
+
+for j in [1:Ncold]
         
 "Vapourisation Fraction Cold Stream"
-        Outlet.Cold.v = Inlet.Cold.v;   
+        Outlet.Cold(j).v = PP.VapourFraction(Outlet.Cold(j).T,Outlet.Cold(j).P,Outlet.Cold(j).z);
         
+end
+        
+
 "Heat Duty Hot Stream"
         Q =  sum(Inlet.Hot.F*(Inlet.Hot.h- Outlet.Hot.h));
@@ -131 +147 @@
         Q=UA*LMTD;
 
-#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
-#       Flow Direction 
-#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
+        
+if abs(DT0 - DTL) > 0.05*max(abs([DT0,DTL])) 
+        
+        then
+"Log Mean Temperature Difference"
+        LMTD= (DT0-DTL)/ln(DT0/DTL);
+
+        else
+        
+if DT0*DTL equal 0
+        
+        then
+"Log Mean Temperature Difference"
+        LMTD = 0.5*(DT0+DTL);
+        
+        else
+"Log Mean Temperature Difference"
+        LMTD = 0.5*(DT0+DTL)*(1-(DT0-DTL)^2/(DT0*DTL)*(1+(DT0-DTL)^2/(DT0*DTL)/2)/12);
+        
+end
+        
+end     
+
 
 if Side equal 0 
         
         then
-"Cocurrent Flow LMTD"
-        LMTD = HE.CocurrentLMTD(max(Inlet.Hot.T),min(Outlet.Hot.T),min(Inlet.Cold.T),max(Outlet.Cold.T));
+        
+"Temperature Difference at Inlet"
+        DT0 = max(Inlet.Hot.T) - min(Inlet.Cold.T);
+
+"Temperature Difference at Outlet"
+        DTL = min(Outlet.Hot.T) - max(Outlet.Cold.T);
         
         else
-"Counter Flow LMTD"
-        LMTD = HE.CounterLMTD(max(Inlet.Hot.T),min(Outlet.Hot.T),max(Inlet.Cold.T),min(Outlet.Cold.T));
+        
+"Temperature Difference at Inlet"
+        DT0 = max(Inlet.Hot.T) - max(Outlet.Cold.T);
+
+"Temperature Difference at Outlet"
+        DTL = min(Outlet.Hot.T) - min(Inlet.Cold.T);
         
 end