source: trunk/eml/heat_exchangers/Mheatex.mso @ 636

#*-------------------------------------------------------------------
* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
*
* This LIBRARY is free software; you can distribute it and/or modify
* it under the therms of the ALSOC FREE LICENSE as available at
* http://www.enq.ufrgs.br/alsoc.
*
* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
* from http://www.rps.eng.br Copyright (C) 2002-2004.
* All rights reserved.
*
* EMSO is distributed under the therms of the ALSOC LICENSE as
* available at http://www.enq.ufrgs.br/alsoc.
*----------------------------------------------------------------------
* Author: Gerson Balbueno Bicca 
* $Id: Mheatex.mso 544 2008-06-27 15:23:00Z bicca $
*--------------------------------------------------------------------*#

using "HEX_Engine.mso";

Model Mheatex
        
ATTRIBUTES
        Icon = "icon/Mheatex";
        Pallete = true;
        Brief = "Model of a Multistream heat exchangers";
        Info            =
"Heat Transfer between multiple hot and cold streams.

== Specify ==
The user must specify the following variables:
* The Inlet Hot streams: Any Number
* The Inlet Cold streams: Any Number
* The LMTD correction factor
* The outlet temperature and the outlet pressure for each stream on one side (hot or cold) of the heat exchanger
* On the other side the user must leave at least one unespecified outlet stream.

== Setting The Mheatex Parameters ==
* FlowDirection: counter or cocurrent flow
* Number of hot streams (Nhot)
* Number of cold streams (Ncold)
";

PARAMETERS

outer PP                        as Plugin       (Brief="Physical Properties", Type="PP");
outer NComp             as Integer      (Brief="Number of Components"); 
        FlowDirection   as Switcher     (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent");
        Ncold                   as Integer      (Brief="Number of Inlet Cold Streams",Lower=1, Symbol = "N_{cold}");
        Nhot                    as Integer      (Brief="Number of Inlet Hot Streams",Lower=1, Symbol = "N_{hot}");
        
VARIABLES

in  InletHot(Nhot)      as stream       (Brief="Inlet Hot Streams", PosX=0, PosY=0.7156, Symbol="_{hot}^{in}"); 
out OutletHot(Nhot)     as streamPH (Brief="Outlet Hot Streams", PosX=1, PosY=0.7156, Symbol="_{hot}^{out}");
in  InletCold(Ncold)    as stream       (Brief="Inlet Cold Streams", PosX=1, PosY=0.2793, Symbol="_{cold}^{in}");
out OutletCold(Ncold)   as streamPH     (Brief="Outlet Cold Streams", PosX=0, PosY=0.2793, Symbol="_{cold}^{out}");

        Method  as LMTD_Basic   (Brief="Log Mean Temperature Difference Method", Symbol = " ");
        Q               as power        (Brief="Heat Transfer", Default=7000, Lower=1e-6, Upper=1e10);
        UA              as Real     (Brief="UA product",Unit='W/K',Lower=1e-8);
        
EQUATIONS

"Hot Flow"
        OutletHot.F = InletHot.F;       

"Cold Flow"
        OutletCold.F = InletCold.F;
        
"Hot Composition"
        OutletHot.z = InletHot.z;
        
"Cold Composition"
        OutletCold.z = InletCold.z;
        
"Heat Duty Hot Stream"
        Q =  sum(InletHot.F*(InletHot.h- OutletHot.h));
        
"Heat Duty Cold Stream"
        Q = -sum(InletCold.F*(InletCold.h- OutletCold.h));
        
"Heat Duty"
        Q = UA*Method.LMTD*Method.Fc;

switch FlowDirection
        
case    "cocurrent":

"Temperature Difference at Inlet"
        Method.DT0 = max(InletHot.T) - min(InletCold.T);

"Temperature Difference at Outlet"
        Method.DTL = min(OutletHot.T) - max(OutletCold.T);
        
case "counter":
        
"Temperature Difference at Inlet"
        Method.DT0 = max(InletHot.T) - max(OutletCold.T);

"Temperature Difference at Outlet"
        Method.DTL = min(OutletHot.T) - min(InletCold.T);
        
end

end