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 351 2007-08-30 01:00:58Z 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=0); |
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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 | Pdiff as press_delta (Brief = "Pressure Increase", DisplayUnit='kPa'); |
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51 | Pratio as positive (Brief = "Pressure Ratio"); |
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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 | "Calculate Outlet Stream Pressure" |
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71 | Outlet.P = Inlet.P + Pdiff; |
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72 | |
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73 | "Pratio Definition" |
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74 | Outlet.P = Inlet.P * Pratio; |
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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 | "Molar Balance" |
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109 | Outlet.F = Inlet.F; |
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110 | |
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111 | Outlet.z = Inlet.z; |
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112 | end |
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