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/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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