Ignore:
Timestamp:
Aug 15, 2008, 10:31:59 PM (14 years ago)
Author:
gerson bicca
Message:

updated equations for compressor model

File:
1 edited

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  • branches/gui/eml/pressure_changers/compressor.mso

    r598 r599  
    2121
    2222Model centrifugal_compressor
     23       
     24# Do Not Forget to Update The Losses by Mechanical Efficiency !!!!
    2325
    2426ATTRIBUTES
     
    3840VARIABLES
    3941
    40         PolyCoeff       as positive             (Brief = "Polytropic Coefficient", Lower=0);
    41         IseCoeff        as positive     (Brief = "Isentropic Coefficient", Lower=1e-3);
    42         Cp              as cp_mol               (Brief = "Heat Capacity");
    43         Cv                      as cv_mol               (Brief = "Heat Capacity");
     42        PolyCoeff       as positive             (Brief = "Polytropic Coefficient", Lower=1E-6);
     43        IseCoeff        as positive     (Brief = "Isentropic Coefficient", Lower=1E-6);
     44        Cp              as cp_mol               (Brief = "Heat Capacity at constant Pressure");
     45        Cv                      as cv_mol               (Brief = "Heat Capacity at constant Volume");
    4446        Pratio          as positive             (Brief = "Pressure Ratio", Symbol ="P_{ratio}");       
    4547        Pdrop           as press_delta  (Brief = "Pressure Drop", DisplayUnit = 'kPa', Symbol ="\Delta P");
     48        Pincrease       as press_delta  (Brief = "Pressure Increase", DisplayUnit = 'kPa', Symbol ="P_{incr}");
    4649
    47         Head            as energy_mass  (Brief = "Isentropic Head");
     50        Head            as energy_mass  (Brief = "Head");
    4851        Tiso            as temperature  (Brief = "Isentropic Temperature");
    4952       
     
    8689        Outlet.P  = Inlet.P - Pdrop;
    8790
     91"Pressure Increase"
     92        Outlet.P  = Inlet.P + Pincrease;
     93
    8894"Mass Density"
    8995        rho = PP.VapourDensity(Inlet.T, Inlet.P, Inlet.z);
     
    104110        IseCoeff * Cv = Cp;
    105111
    106 #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    107112switch CompressorType
    108113       
     
    110115       
    111116"Isentropic Head"
    112         Head = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(IseCoeff/(IseCoeff-1))*Rgas*Inlet.T*((Outlet.P/Inlet.P)^((IseCoeff-1)/IseCoeff) - 1);
     117        Head = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(IseCoeff/(IseCoeff-1.001))*Rgas*Inlet.T*((Outlet.P/Inlet.P)^((IseCoeff-1.001)/IseCoeff) - 1);
    113118
    114119"Fluid Power"
    115120        FluidPower*IsentropicEff = Head*sum(Mw*Inlet.z)*Inlet.F;
    116121
     122"Discharge Temperature"
     123        Outlet.T = Inlet.T*((Outlet.P/Inlet.P)^((IseCoeff-1.001)/IseCoeff));
     124
    117125        case "Polytropic Operation":
    118126       
    119127"Polytropic Head"
    120         Head = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(PolyCoeff/(PolyCoeff-1))*Rgas*Inlet.T*((Outlet.P/Inlet.P)^((PolyCoeff-1)/PolyCoeff) - 1);
     128        Head = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(PolyCoeff/(PolyCoeff-1.001))*Rgas*Inlet.T*((Outlet.P/Inlet.P)^((PolyCoeff-1.001)/PolyCoeff) - 1);
    121129
    122130"Fluid Power"
    123131        FluidPower*PolytropicEff = Head*sum(Mw*Inlet.z)*Inlet.F;
     132
     133"Discharge Temperature"
     134        Outlet.T = Inlet.T*((Outlet.P/Inlet.P)^((PolyCoeff-1.001)/PolyCoeff));
    124135
    125136end
     
    128139        PP.VapourEntropy(Tiso, Outlet.P, Outlet.z) = PP.VapourEntropy(Inlet.T, Inlet.P, Inlet.z);
    129140
    130 "Discharge Temperature"
    131         IsentropicEff * (Outlet.T- Inlet.T) = (Tiso - Inlet.T);
     141#"Calculate Politropic Coefficient"
     142        #PolyCoeff*(ln(Outlet.T/Inlet.T)) = (PolyCoeff-1)*(ln(Outlet.P/Inlet.P));
    132143
    133 "Calculate Politropic Coefficient"
    134         PolyCoeff*(ln(Outlet.T/Inlet.T)) = (PolyCoeff-1)*(ln(Outlet.P/Inlet.P));
    135 
    136 #"Polytropic Efficiency"
    137         #PolytropicEff * (PolyCoeff-1) * IseCoeff = PolyCoeff * (IseCoeff-1);
     144"Polytropic Efficiency"
     145        PolytropicEff * (PolyCoeff-1) * IseCoeff = PolyCoeff * (IseCoeff-1);
    138146
    139147"Fluid Power"
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