Changeset 136 for trunk/eml/heat_exchangers/DoublePipe.mso

Timestamp:

Jan 25, 2007, 6:59:01 PM (16 years ago)

Author:

gerson bicca

Message:

solved convergence problem for multitubular heat exchanger

File:

• trunk/eml/heat_exchangers/DoublePipe.mso (modified) (2 diffs)

trunk/eml/heat_exchangers/DoublePipe.mso

@@ -628 +628 @@
 
 "Overall Heat Transfer Coefficient Clean"
-        Unity(i).Details.Uc*(Unity(i).Resistances.Rtube+Unity(i).Resistances.Rwall+Unity(i).Resistances.Rshell)=1;
+        (1/Unity(i).Details.Ud)=(1/Unity(i).Details.Uc)+Unity(i).Resistances.Rfo+Unity(i).Resistances.Rfi*(DoInner/DiInner);
+
 
 "Overall Heat Transfer Coefficient Dirty"
-        Unity(i).Details.Ud*(Unity(i).Resistances.Rfi*(DoInner/DiInner) + Unity(i).Resistances.Rfo + Unity(i).Resistances.Rtube + Unity(i).Resistances.Rwall + Unity(i).Resistances.Rshell)=1;
+        Unity(i).Details.Ud=1/(DoInner/(Unity(i).Inner.HeatTransfer.hcoeff*DiInner)+Unity(i).Resistances.Rfo+Unity(i).Resistances.Rfi*(DoInner/DiInner)+(DoInner*ln(DoInner/DiInner)/(2*Kwall))+(1/(Unity(i).Outer.HeatTransfer.hcoeff)));
 
 "Exchange Surface Area"
@@ -793 +794 @@
 
 "Exchange Surface Area"
-        Unity(i).Details.Q = Unity(i).Details.Ud*Unity(i).Details.A*LMTD(i);
+        Unity(i).Details.Q = Unity(i).Details.Ud*Pi*DoInner*Lpipe*LMTD(i);
 
 end