source: mso/eml/pressure_changers/compressor.mso @ 78

#*-------------------------------------------------------------------
* 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 centrifugal compressor
*--------------------------------------------------------------------
*       - Assumptions
*               * Steady State
*               * Only Vapour
*               * Adiabatic
*
*----------------------------------------------------------------------
* Author: Marcos L. Alencastro,  Estefane S. Horn
* $Id: compressor.mso 77 2006-12-08 19:21:59Z paula $
*--------------------------------------------------------------------*#

using "pressure_changers/flux_machine_basic";

Model centrifugal_compressor as flux_machine_basic_TP
        
        PARAMETERS
ext PP                  as CalcObject   (Brief = "External Physical Properties");
ext NComp       as Integer              (Brief = "Number of chemical components", Lower = 1);
        Effs            as positive     (Default = 0.72, Brief = "Isentropic efficiency", Lower = 0, Upper = 1);
        R                       as positive     (Default = 8.31451, Brief = "Constant of Gases", Unit= "kJ/kmol/K");
        Mw(NComp)       as molweight    (Brief = "Molar Weight");
        
        VARIABLES
        n                       as positive             (Brief = "Politropic Coefficient");
        k                       as positive     (Brief = "Isentropic Coefficient"); 
        Cp              as cp_mol               (Brief = "Heat Capacity", Unit = "kJ/(kmol*K)");
        Cv                      as cv_mol               (Brief = "Heat Capacity", Unit = "kJ/(kmol*K)");        
        Pdiff           as press_delta  (Brief = "Pressure Increase", Unit="kPa");
        Pratio          as positive             (Brief = "Pressure Ratio");     
        Wp                      as energy_mol   (Brief = "Politropic Head", Unit = "kJ/kmol");
        Ws                      as energy_mol   (Brief = "Isentropic Head", Unit = "kJ/kmol");
        Tiso            as temperature  (Brief = "Isentropic Temperature"); 
        Effp            as positive     (Brief = "Politropic efficiency", Lower = 0, Upper = 1);
        FPower          as power                (Brief = "Fluid Power", Unit="kW");
        Mwm                     as molweight    (Brief = "Mixture Molar Weight");
        
        SET
        Mw = PP.MolecularWeight();
        
        EQUATIONS
        
        "Calculate Mwm for Inlet Mixture"
        Mwm = sum(Mw([1:NComp])*Inlet.z([1:NComp]));

        "Calculate Outlet Stream Pressure"
        Outlet.P = Inlet.P + Pdiff;
        
        "Pratio Definition"
        Outlet.P = Inlet.P * Pratio;
        
        "Calculate Cp Using a External Physical Properties Routine"
        Cp = PP.VapourCp(Inlet.T,Inlet.P,Inlet.z);
        
        "Calculate Cv Using a External Physical Properties Routine"
        Cv = PP.VapourCv(Inlet.T,Inlet.P,Inlet.z);
        
        "Calculate Isentropic Coeficient"
        k = Cp/Cv;
        
        "Calculate Isentropic Head"
        Ws = (k/(k-1))*R*Inlet.T*((Outlet.P/Inlet.P)^((k-1)/k) - 1);
        
        "Calculate Isentropic Outlet Temperature"
        Tiso = Inlet.T * (Outlet.P/Inlet.P)^((k-1)/k);
        
        "Calculate Real Outlet Temperature"
        Effs * (Outlet.T- Inlet.T) = (Tiso - Inlet.T);
        
        "Calculate Politropic Coefficient"
        Outlet.T = Inlet.T * (Outlet.P/Inlet.P)^((n-1)/n);
        
        "Calculate Politropic Efficiency"
        Effp = (n/(n-1))/(k/(k-1));
        
        "Calculate Politropic Head"
        Ws*Effp = Wp*Effs;

        "Calculate Fluid Power"
        FPower*Effs = Inlet.F*Ws;
        
        "Molar Balance"
        Outlet.F = Inlet.F;
        
        Outlet.z = Inlet.z;


end