[393] | 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 |
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| 17 | * $Id: compressor.mso 393 2007-10-17 23:50:09Z arge $ |
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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 | ATTRIBUTES |
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| 24 | Pallete = true; |
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| 25 | Icon = "icon/CentrifugalCompressor"; |
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| 26 | Brief = "Model of a centrifugal compressor."; |
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| 27 | Info = |
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| 28 | "== Assumptions == |
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| 29 | * Steady State; |
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| 30 | * Only Vapor; |
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| 31 | * Adiabatic. |
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| 32 | |
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| 33 | == Specify == |
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| 34 | * the inlet stream; |
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| 35 | * the outlet pressure (Outlet.P); |
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| 36 | * the Isentropic efficiency (Effs). |
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| 37 | "; |
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| 38 | |
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| 39 | PARAMETERS |
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| 40 | outer PP as Plugin (Brief = "External Physical Properties", Type="PP"); |
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| 41 | outer NComp as Integer (Brief = "Number of chemical components", Lower = 1); |
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| 42 | R as positive (Default = 8.31451, Brief = "Constant of Gases", Unit= 'kJ/kmol/K'); |
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| 43 | Mw(NComp) as molweight (Brief = "Molar Weight"); |
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| 44 | |
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| 45 | VARIABLES |
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| 46 | n as positive (Brief = "Politropic Coefficient", Lower=0); |
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| 47 | k as positive (Brief = "Isentropic Coefficient", Lower=1e-3); |
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| 48 | Cp as cp_mol (Brief = "Heat Capacity"); |
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| 49 | Cv as cv_mol (Brief = "Heat Capacity"); |
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| 50 | Pratio as positive (Brief = "Pressure Ratio", 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 | Wp as energy_mol (Brief = "Politropic Head"); |
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| 53 | Ws as energy_mol (Brief = "Isentropic Head"); |
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| 54 | Tiso as temperature (Brief = "Isentropic Temperature"); |
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| 55 | Effp as positive (Brief = "Politropic efficiency"); |
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| 56 | Effs as efficiency (Brief = "Isentropic efficiency"); |
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| 57 | FPower as power (Brief = "Fluid Power"); |
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| 58 | Mwm as molweight (Brief = "Mixture Molar Weight"); |
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| 59 | in Inlet as stream (Brief = "Inlet stream", PosX=0, PosY=0.5086, Symbol="_{in}"); |
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| 60 | out Outlet as streamPH (Brief = "Outlet stream", PosX=1, PosY=0.5022, Symbol="_{out}"); |
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| 61 | |
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| 62 | SET |
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| 63 | Mw = PP.MolecularWeight(); |
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| 64 | |
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| 65 | EQUATIONS |
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| 66 | |
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| 67 | "Calculate Mwm for Inlet Mixture" |
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| 68 | Mwm = sum(Mw*Inlet.z); |
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| 69 | |
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| 70 | "Pressure Ratio" |
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| 71 | Outlet.P = Inlet.P * Pratio; |
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| 72 | |
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| 73 | "Pressure Drop" |
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| 74 | Outlet.P = Inlet.P - Pdrop; |
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| 75 | |
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| 76 | "Calculate Cp Using a External Physical Properties Routine" |
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| 77 | Cp = PP.VapourCp(Inlet.T,Inlet.P,Inlet.z); |
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| 78 | |
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| 79 | "Calculate Cv Using a External Physical Properties Routine" |
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| 80 | Cv = PP.VapourCv(Inlet.T,Inlet.P,Inlet.z); |
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| 81 | |
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| 82 | "Calculate Isentropic Coeficient" |
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| 83 | k * Cv = Cp; |
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| 84 | |
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| 85 | "Calculate Isentropic Head" |
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| 86 | Ws = (k/(k-1))*R*Inlet.T*((Outlet.P/Inlet.P)^((k-1)/k) - 1); |
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| 87 | |
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| 88 | "Calculate Isentropic Outlet Temperature" |
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| 89 | # Tiso = Inlet.T * (Outlet.P/Inlet.P)^((k-1)/k); |
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| 90 | PP.VapourEntropy(Tiso, Outlet.P, Outlet.z) = |
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| 91 | PP.VapourEntropy(Inlet.T, Inlet.P, Inlet.z); |
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| 92 | |
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| 93 | "Calculate Real Outlet Temperature" |
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| 94 | Effs * (Outlet.T- Inlet.T) = (Tiso - Inlet.T); |
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| 95 | |
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| 96 | "Calculate Politropic Coefficient" |
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| 97 | n*(ln(Outlet.T/Inlet.T)) = (n-1)*(ln(Outlet.P/Inlet.P)); |
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| 98 | |
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| 99 | "Calculate Politropic Efficiency" |
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| 100 | Effp * (n-1) * k = n * (k-1); |
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| 101 | |
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| 102 | "Calculate Politropic Head" |
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| 103 | Ws*Effp = Wp*Effs; |
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| 104 | |
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| 105 | "Calculate Fluid Power" |
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| 106 | FPower*Effs = Inlet.F*Ws; |
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| 107 | |
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| 108 | "Overall Molar Balance" |
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| 109 | Outlet.F = Inlet.F; |
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| 110 | |
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| 111 | "Component Molar Balance" |
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| 112 | Outlet.z = Inlet.z; |
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| 113 | end |
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