| 1 | #*------------------------------------------------------------------- |
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| 2 | * EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC. |
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| 3 | * |
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| 4 | * This LIBRARY is free software; you can distribute it and/or modify |
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| 5 | * it under the therms of the ALSOC FREE LICENSE as available at |
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| 6 | * http://www.enq.ufrgs.br/alsoc. |
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| 7 | * |
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| 8 | * EMSO Copyright (C) 2004 - 2007 ALSOC, original code |
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| 9 | * from http://www.rps.eng.br Copyright (C) 2002-2004. |
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| 10 | * All rights reserved. |
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| 11 | * |
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| 12 | * EMSO is distributed under the therms of the ALSOC LICENSE as |
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| 13 | * available at http://www.enq.ufrgs.br/alsoc. |
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| 14 | * |
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| 15 | *---------------------------------------------------------------------- |
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| 16 | * Author: Marcos L. Alencastro, Estefane S. Horn (Revised Gerson B. Bicca) |
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| 17 | * $Id: compressor.mso 864 2009-10-19 19:41:09Z bicca $ |
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| 18 | *--------------------------------------------------------------------*# |
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| 19 | |
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| 20 | using "streams"; |
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| 21 | |
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| 22 | Model centrifugal_compressor |
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| 23 | |
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| 24 | ATTRIBUTES |
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| 25 | Pallete = true; |
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| 26 | Icon = "icon/CentrifugalCompressor"; |
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| 27 | Brief = "Model of a centrifugal compressor."; |
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| 28 | Info = |
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| 29 | "To be documented |
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| 30 | |
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| 31 | == References == |
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| 32 | |
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| 33 | [1] GPSA, 1979, Engineering Data Book, Chapter 4, 5-9 - 5-10. |
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| 34 | |
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| 35 | [2] Bloch, Heinz P., A Practical Guide to Compressor Technology, John Wiley & Sons, Incorporate, 2006. |
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| 36 | |
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| 37 | [3] Mark R. Sandberg, Equation Of State Influences On Compressor Performance Determination,PROCEEDINGS OF THE THIRTY-FOURTH TURBOMACHINERY SYMPOSIUM, 2005."; |
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| 38 | |
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| 39 | PARAMETERS |
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| 40 | |
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| 41 | outer PP as Plugin (Brief = "External Physical Properties", Type="PP"); |
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| 42 | outer NComp as Integer (Brief = "Number of chemical components", Lower = 1); |
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| 43 | Rgas as positive (Brief = "Constant of Gases", Unit= 'kJ/kmol/K', Default = 8.31451,Hidden=true); |
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| 44 | Mw(NComp) as molweight (Brief = "Molar Weight",Hidden=true); |
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| 45 | CompressorOperation as Switcher (Brief = "Compressor Operation Model",Valid=["Polytropic","Isentropic"], Default="Isentropic"); |
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| 46 | Method as Switcher (Brief = "Method of Calculation",Valid=["GPSA Method","ASME Method"], Default="GPSA Method"); |
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| 47 | |
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| 48 | VARIABLES |
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| 49 | |
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| 50 | Pratio as positive (Brief = "Pressure Ratio", Lower = 1E-6, Symbol ="P_{ratio}"); |
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| 51 | Pdrop as press_delta (Brief = "Pressure Drop", DisplayUnit = 'kPa', Symbol ="\Delta P"); |
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| 52 | Pincrease as press_delta (Brief = "Pressure Increase",Lower = 0, DisplayUnit = 'kPa', Symbol ="P_{incr}"); |
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| 53 | EfficiencyOperation as positive (Brief = "Compressor efficiency - Polytropic or Isentropic (See Compressor Type)",Lower=1E-3,Upper=1); |
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| 54 | MechanicalEff as positive (Brief = "Mechanical efficiency",Lower=1E-3,Upper=1); |
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| 55 | PowerLoss as power (Brief = "Power Losses"); |
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| 56 | Head as energy_mass (Brief = "Actual Head", Protected=true); |
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| 57 | HeadIsentropic as energy_mass (Brief = "Isentropic Head", Protected=true); |
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| 58 | HeadPolytropic as energy_mass (Brief = "Polytropic Head", Protected=true); |
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| 59 | HeadCorrection as positive (Brief = "Schultz Polytropic Head Correction", Protected=true); |
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| 60 | |
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| 61 | FluidPower as power (Brief = "Fluid Power", Protected=true); |
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| 62 | BrakePower as power (Brief = "Brake Power", Protected=true); |
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| 63 | |
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| 64 | PolyCoeff as positive (Brief = "Polytropic Coefficient", Lower=0.2,Protected=true); |
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| 65 | IseCoeff as positive (Brief = "Isentropic Coefficient", Lower=0.2,Protected=true); |
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| 66 | PolytropicEff as positive (Brief = "Polytropic efficiency",Lower=1E-3,Upper=1,Protected=true); |
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| 67 | IsentropicEff as positive (Brief = "Isentropic efficiency",Lower=1E-3,Upper=1,Protected=true); |
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| 68 | |
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| 69 | Tisentropic as temperature (Brief = "Isentropic Temperature",Protected=true); |
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| 70 | hise as enth_mol (Brief = "Enthalpy at constant entropy",Hidden=true); |
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| 71 | Mwm as molweight (Brief = "Mixture Molar Weight",Hidden=true); |
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| 72 | rho_in as dens_mass (Brief = "Mass Density at inlet conditions", Lower = 1E-6, Protected=true); |
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| 73 | rho_out as dens_mass (Brief = "Mass Density at outlet conditions", Lower = 1E-6, Protected=true); |
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| 74 | rho_ise as dens_mass (Brief = "Mass Density at isentropic conditions", Lower = 1E-6, Hidden=true); |
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| 75 | Zfac_in as fraction (Brief = "Compressibility factor at inlet", Lower = 1E-3, Protected=true); |
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| 76 | Zfac_out as fraction (Brief = "Compressibility factor at outlet", Lower = 1E-3, Protected=true); |
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| 77 | |
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| 78 | in Inlet as stream (Brief = "Inlet stream", PosX=0.16, PosY=1, Symbol="_{in}"); |
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| 79 | out Outlet as streamPH (Brief = "Outlet stream", PosX=0.87, PosY=0.0, Symbol="_{out}"); |
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| 80 | |
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| 81 | in WorkIn as power (Brief = "Work Inlet", PosX=0, PosY=0.45, Protected=true); |
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| 82 | |
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| 83 | SET |
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| 84 | |
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| 85 | Mw = PP.MolecularWeight(); |
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| 86 | |
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| 87 | Rgas = 8.31451*'kJ/kmol/K'; |
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| 88 | |
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| 89 | EQUATIONS |
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| 90 | |
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| 91 | "Overall Molar Balance" |
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| 92 | Outlet.F = Inlet.F; |
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| 93 | |
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| 94 | "Component Molar Balance" |
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| 95 | Outlet.z = Inlet.z; |
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| 96 | |
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| 97 | "Average Molecular Weight" |
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| 98 | Mwm = sum(Mw*Inlet.z); |
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| 99 | |
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| 100 | "Pressure Ratio" |
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| 101 | Outlet.P = Inlet.P * Pratio; |
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| 102 | |
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| 103 | "Pressure Drop" |
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| 104 | Outlet.P = Inlet.P - Pdrop; |
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| 105 | |
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| 106 | "Pressure Increase" |
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| 107 | Outlet.P = Inlet.P + Pincrease; |
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| 108 | |
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| 109 | "Mass Density at inlet conditions" |
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| 110 | rho_in = PP.VapourDensity(Inlet.T, Inlet.P, Inlet.z); |
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| 111 | |
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| 112 | "Mass Density at outlet conditions" |
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| 113 | rho_out= PP.VapourDensity(Outlet.T, Outlet.P, Outlet.z); |
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| 114 | |
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| 115 | "Mass Density at isentropic conditions" |
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| 116 | rho_ise= PP.VapourDensity(Tisentropic, Outlet.P, Outlet.z); |
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| 117 | |
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| 118 | "Enthalpy at isentropic conditions" |
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| 119 | hise = PP.VapourEnthalpy(Tisentropic, Outlet.P, Outlet.z); |
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| 120 | |
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| 121 | "Compressibility factor at Inlet Conditions" |
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| 122 | Zfac_in = PP.VapourCompressibilityFactor(Inlet.T,Inlet.P,Inlet.z); |
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| 123 | |
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| 124 | "Compressibility factor at Outlet Conditions" |
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| 125 | Zfac_out = PP.VapourCompressibilityFactor(Outlet.T,Outlet.P,Outlet.z); |
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| 126 | |
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| 127 | "Isentropic Efficiency" |
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| 128 | IsentropicEff*(Outlet.h-Inlet.h) = (hise-Inlet.h); |
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| 129 | |
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| 130 | "Actual Head" |
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| 131 | Head*Mwm = (Outlet.h-Inlet.h); |
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| 132 | |
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| 133 | "Isentropic Outlet Temperature" |
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| 134 | PP.VapourEntropy(Tisentropic, Outlet.P, Outlet.z) = PP.VapourEntropy(Inlet.T, Inlet.P, Inlet.z); |
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| 135 | |
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| 136 | "Brake Power" |
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| 137 | BrakePower = -WorkIn; |
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| 138 | |
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| 139 | "Brake Power" |
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| 140 | BrakePower*MechanicalEff = FluidPower; |
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| 141 | |
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| 142 | "Power Loss" |
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| 143 | PowerLoss = BrakePower - FluidPower; |
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| 144 | |
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| 145 | "Polytropic-Isentropic Relation" |
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| 146 | PolytropicEff*HeadIsentropic = HeadPolytropic*IsentropicEff; |
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| 147 | |
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| 148 | "Fluid Power" |
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| 149 | FluidPower = Head*Mwm*Inlet.F; |
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| 150 | |
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| 151 | switch CompressorOperation |
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| 152 | |
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| 153 | case "Isentropic": |
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| 154 | |
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| 155 | switch Method |
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| 156 | |
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| 157 | case "ASME Method": |
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| 158 | |
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| 159 | "Efficiency" |
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| 160 | EfficiencyOperation = IsentropicEff; |
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| 161 | |
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| 162 | "Isentropic Coefficient" |
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| 163 | IseCoeff*ln(rho_ise/rho_in) = ln(Outlet.P/Inlet.P); |
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| 164 | |
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| 165 | "Polytropic Coefficient" |
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| 166 | PolyCoeff*ln(rho_out/rho_in) = ln(Outlet.P/Inlet.P); |
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| 167 | |
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| 168 | "Isentropic Head" |
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| 169 | HeadIsentropic*rho_in = (IseCoeff/(IseCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1); |
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| 170 | |
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| 171 | "Polytropic Head" |
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| 172 | HeadPolytropic*rho_in = (PolyCoeff/(PolyCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1); |
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| 173 | |
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| 174 | "Schultz Polytropic Head Correction" |
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| 175 | HeadCorrection*Mwm*(IseCoeff/(IseCoeff-1.001))*(Outlet.P/rho_ise -Inlet.P/rho_in) = (hise-Inlet.h); |
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| 176 | |
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| 177 | case "GPSA Method": |
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| 178 | |
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| 179 | "Efficiency" |
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| 180 | EfficiencyOperation = IsentropicEff; |
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| 181 | |
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| 182 | "Polytropic Efficiency" |
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| 183 | PolytropicEff*IseCoeff*(PolyCoeff-1) = PolyCoeff*(IseCoeff-1); |
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| 184 | |
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| 185 | "Isentropic Coefficient" |
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| 186 | HeadIsentropic*Mwm*((IseCoeff-1.001)/IseCoeff) = (0.5*Zfac_in+0.5*Zfac_out)*Rgas*Inlet.T*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1); |
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| 187 | |
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| 188 | "Polytropic Coefficient" |
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| 189 | HeadPolytropic*Mwm*((PolyCoeff-1.001)/PolyCoeff) = (0.5*Zfac_in+0.5*Zfac_out)*Rgas*Inlet.T*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1); |
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| 190 | |
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| 191 | "Head Correction" |
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| 192 | HeadCorrection =1; |
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| 193 | |
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| 194 | "Isentropic Head" |
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| 195 | HeadIsentropic = Head*IsentropicEff; |
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| 196 | |
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| 197 | end |
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| 198 | |
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| 199 | case "Polytropic": |
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| 200 | |
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| 201 | switch Method |
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| 202 | |
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| 203 | case "GPSA Method": |
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| 204 | |
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| 205 | "Efficiency" |
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| 206 | EfficiencyOperation = PolytropicEff; |
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| 207 | |
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| 208 | "Polytropic Efficiency" |
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| 209 | PolytropicEff*IseCoeff*(PolyCoeff-1) = PolyCoeff*(IseCoeff-1); |
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| 210 | |
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| 211 | "Isentropic Coefficient" |
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| 212 | HeadIsentropic*Mwm*((IseCoeff-1.001)/IseCoeff) = (0.5*Zfac_in+0.5*Zfac_out)*Rgas*Inlet.T*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1); |
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| 213 | |
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| 214 | "Polytropic Coefficient" |
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| 215 | HeadPolytropic*Mwm*((PolyCoeff-1.001)/PolyCoeff) = (0.5*Zfac_in+0.5*Zfac_out)*Rgas*Inlet.T*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1); |
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| 216 | |
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| 217 | "Head Correction" |
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| 218 | HeadCorrection =1; |
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| 219 | |
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| 220 | "Isentropic Head" |
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| 221 | HeadIsentropic = Head*IsentropicEff; |
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| 222 | |
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| 223 | case "ASME Method": |
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| 224 | |
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| 225 | "Efficiency" |
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| 226 | EfficiencyOperation = PolytropicEff; |
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| 227 | |
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| 228 | "Isentropic Coefficient" |
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| 229 | IseCoeff*ln(rho_ise/rho_in) = ln(Outlet.P/Inlet.P); |
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| 230 | |
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| 231 | "Polytropic Coefficient" |
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| 232 | PolyCoeff*ln(rho_out/rho_in) = ln(Outlet.P/Inlet.P); |
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| 233 | |
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| 234 | "Isentropic Head" |
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| 235 | HeadIsentropic*rho_in = (IseCoeff/(IseCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1); |
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| 236 | |
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| 237 | "Polytropic Head" |
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| 238 | HeadPolytropic*rho_in = (PolyCoeff/(PolyCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1); |
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| 239 | |
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| 240 | "Schultz Polytropic Head Correction" |
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| 241 | HeadCorrection*Mwm*(IseCoeff/(IseCoeff-1.001))*(Outlet.P/rho_ise -Inlet.P/rho_in) = (hise-Inlet.h); |
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| 242 | end |
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| 243 | |
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| 244 | end |
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| 245 | |
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| 246 | end |
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