source: branches/newlanguage/eml/heat_exchangers/Mheatex.mso @ 147

#*-------------------------------------------------------------------
* 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.
*
*
*---------------------------------------------------------------------
* Model of a Multistream Heat Exchanger
*
*       Streams:
*               * 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:
*               * Heat Transfer between multiple hot and cold streams.
*
*----------------------------------------------------------------------
* Author: Gerson Balbueno Bicca 
* $Id: Mheatex.mso 147 2007-01-31 19:02:46Z bicca $
*--------------------------------------------------------------------*#

using "streams.mso";

Model Inlet_Main_Stream         

ATTRIBUTES
        Pallete = false;
        Brief = "Inlet material streams for Hot and Cold side";
        Info =
        "write some information";
        
PARAMETERS

outer   Ncold   as Integer      (Brief="Number of Inlet Cold Streams",Lower=1);
outer   Nhot    as Integer      (Brief="Number of Inlet Hot Streams",Lower=1);

VARIABLES

        Hot  (Nhot)     as stream (Brief="Inlet Hot Streams"); 
        Cold (Ncold)    as stream (Brief="Inlet Cold Streams"); 
        
end

Model Outlet_Main_Stream        

ATTRIBUTES
        Pallete = false;
        Brief = "Outlet material streams for Hot and Cold side";
        Info =
        "write some information";
        
PARAMETERS

outer   Ncold   as Integer      (Brief="Number of Outlet Cold Streams",Lower=1);
outer   Nhot    as Integer      (Brief="Number of Outlet Hot Streams",Lower=1);

VARIABLES

Hot  (Nhot)     as streamPH (Brief="Outlet Hot Streams"); 
Cold (Ncold)    as streamPH (Brief="Outlet Cold Streams"); 
        
end

Model Mheatex
        
ATTRIBUTES
        Pallete = true;
        Brief = "Multistream heat exchangers";
        Info =
        "Heat Transfer between multiple hot and cold streams";
        
PARAMETERS

outer PP                                        as Plugin       (Brief="Physical Properties");
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);
        Nhot                                            as Integer      (Brief="Number of Inlet Hot Streams",Lower=1);
        
VARIABLES

in      Inlet   as Inlet_Main_Stream    (Brief="Inlet Streams");                
out     Outlet  as Outlet_Main_Stream (Brief="Outlet Streams");

        Q               as power                (Brief="Heat Transfer");
        LMTD            as temp_delta   (Brief="Logarithmic Mean Temperature Difference");
        UA              as positive             (Brief="UA product",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);
        
EQUATIONS

"Hot Flow"
        Outlet.Hot.F = Inlet.Hot.F;     

"Cold Flow"
        Outlet.Cold.F = Inlet.Cold.F;
        
"Hot Composition"
        Outlet.Hot.z = Inlet.Hot.z;
        
"Cold Composition"
        Outlet.Cold.z = Inlet.Cold.z;
        
"Heat Duty Hot Stream"
        Q =  sum(Inlet.Hot.F*(Inlet.Hot.h- Outlet.Hot.h));
        
"Heat Duty Cold Stream"
        Q = -sum(Inlet.Cold.F*(Inlet.Cold.h- Outlet.Cold.h));
        
"Heat Duty"
        Q=UA*LMTD;

        
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     


switch FlowDirection
        
case    "cocurrent":

"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);
        
case "counter":
        
"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

end