| 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: Gerson Balbueno Bicca |
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| 17 | * $Id: HeatExchangerSimplified.mso 160 2007-02-08 18:37:44Z bicca $ |
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| 18 | *--------------------------------------------------------------------*# |
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| 19 | |
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| 20 | using "heat_exchangers/HEX_Engine"; |
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| 21 | |
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| 22 | Model HeatExchangerSimplified_Basic |
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| 23 | |
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| 24 | ATTRIBUTES |
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| 25 | Pallete = false; |
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| 26 | Brief = "Basic Models for Simplified Heat Exchangers"; |
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| 27 | Info = |
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| 28 | "write some information"; |
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| 29 | |
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| 30 | PARAMETERS |
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| 31 | outer PP as Plugin (Brief="External Physical Properties", Type="PP"); |
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| 32 | outer NComp as Integer (Brief="Number of Components"); |
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| 33 | |
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| 34 | M(NComp) as molweight (Brief="Component Mol Weight"); |
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| 35 | |
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| 36 | VARIABLES |
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| 37 | |
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| 38 | in InletHot as stream (Brief="Inlet Hot Stream"); |
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| 39 | out OutletHot as streamPH (Brief="Outlet Hot Stream"); |
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| 40 | in InletCold as stream (Brief="Inlet Cold Stream"); |
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| 41 | out OutletCold as streamPH (Brief="Outlet Cold Stream"); |
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| 42 | |
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| 43 | xh(NComp) as fraction(Brief = "Liquid Molar Fraction in Hot Side"); |
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| 44 | yh(NComp) as fraction(Brief = "Vapour Molar Fraction in Hot Side"); |
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| 45 | vh as fraction(Brief = "Vapour Molar Fraction in Hot Side"); |
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| 46 | |
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| 47 | xc(NComp) as fraction(Brief = "Liquid Molar Fraction in Cold Side"); |
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| 48 | yc(NComp) as fraction(Brief = "Vapour Molar Fraction in Cold Side"); |
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| 49 | vc as fraction(Brief = "Vapour Molar Fraction in Cold Side"); |
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| 50 | |
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| 51 | Details as Details_Main (Brief="Heat Exchanger Details"); |
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| 52 | HotSide as Main_Simplified (Brief="Heat Exchanger Hot Side"); |
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| 53 | ColdSide as Main_Simplified (Brief="Heat Exchanger Cold Side"); |
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| 54 | |
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| 55 | SET |
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| 56 | |
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| 57 | #"Component Molecular Weight" |
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| 58 | M = PP.MolecularWeight(); |
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| 59 | |
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| 60 | EQUATIONS |
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| 61 | |
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| 62 | "Flash Calculation in Hot Side" |
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| 63 | [vh, xh, yh] = PP.Flash(InletHot.T, InletHot.P, InletHot.z); |
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| 64 | |
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| 65 | "Flash Calculation in Cold Side" |
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| 66 | [vc, xc, yc] = PP.Flash(InletCold.T, InletCold.P, InletCold.z); |
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| 67 | |
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| 68 | "Hot Stream Average Temperature" |
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| 69 | HotSide.Properties.Average.T = 0.5*InletHot.T + 0.5*OutletHot.T; |
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| 70 | |
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| 71 | "Cold Stream Average Temperature" |
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| 72 | ColdSide.Properties.Average.T = 0.5*InletCold.T + 0.5*OutletCold.T; |
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| 73 | |
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| 74 | "Hot Stream Average Pressure" |
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| 75 | HotSide.Properties.Average.P = 0.5*InletHot.P+0.5*OutletHot.P; |
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| 76 | |
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| 77 | "Cold Stream Average Pressure" |
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| 78 | ColdSide.Properties.Average.P = 0.5*InletCold.P+0.5*OutletCold.P; |
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| 79 | |
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| 80 | "Cold Stream Wall Temperature" |
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| 81 | ColdSide.Properties.Wall.Twall = 0.5*HotSide.Properties.Average.T + 0.5*ColdSide.Properties.Average.T; |
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| 82 | |
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| 83 | "Hot Stream Wall Temperature" |
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| 84 | HotSide.Properties.Wall.Twall = 0.5*HotSide.Properties.Average.T + 0.5*ColdSide.Properties.Average.T; |
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| 85 | |
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| 86 | "Hot Stream Average Molecular Weight" |
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| 87 | HotSide.Properties.Average.Mw = sum(M*InletHot.z); |
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| 88 | |
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| 89 | "Cold Stream Average Molecular Weight" |
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| 90 | ColdSide.Properties.Average.Mw = sum(M*InletCold.z); |
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| 91 | |
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| 92 | "Cold Stream Average Heat Capacity" |
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| 93 | ColdSide.Properties.Average.Cp = (1-InletCold.v)*PP.LiquidCp(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,xc) + |
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| 94 | InletCold.v*PP.VapourCp(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,yc); |
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| 95 | |
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| 96 | "Cold Stream Inlet Heat Capacity" |
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| 97 | ColdSide.Properties.Inlet.Cp = (1-InletCold.v)*PP.LiquidCp(InletCold.T,InletCold.P,xc)+ |
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| 98 | InletCold.v*PP.VapourCp(InletCold.T,InletCold.P,yc); |
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| 99 | |
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| 100 | "Cold Stream Outlet Heat Capacity" |
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| 101 | ColdSide.Properties.Outlet.Cp = (1-OutletCold.v)*PP.LiquidCp(OutletCold.T,OutletCold.P,OutletCold.x)+ |
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| 102 | OutletCold.v*PP.VapourCp(OutletCold.T,OutletCold.P,OutletCold.y); |
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| 103 | |
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| 104 | "Cold Stream Average Mass Density" |
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| 105 | ColdSide.Properties.Average.rho = (1-InletCold.v)*PP.LiquidDensity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,xc)+ |
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| 106 | InletCold.v*PP.VapourDensity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,yc); |
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| 107 | |
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| 108 | "Cold Stream Inlet Mass Density" |
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| 109 | ColdSide.Properties.Inlet.rho = (1-InletCold.v)*PP.LiquidDensity(InletCold.T,InletCold.P,xc)+ |
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| 110 | InletCold.v*PP.VapourDensity(InletCold.T,InletCold.P,yc); |
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| 111 | |
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| 112 | "Cold Stream Outlet Mass Density" |
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| 113 | ColdSide.Properties.Outlet.rho = (1-OutletCold.v)*PP.LiquidDensity(OutletCold.T,OutletCold.P,OutletCold.x)+ |
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| 114 | OutletCold.v*PP.VapourDensity(OutletCold.T,OutletCold.P,OutletCold.y); |
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| 115 | |
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| 116 | "Cold Stream Average Viscosity" |
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| 117 | ColdSide.Properties.Average.Mu = (1-InletCold.v)*PP.LiquidViscosity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,xc)+ |
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| 118 | InletCold.v*PP.VapourViscosity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,yc); |
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| 119 | |
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| 120 | "Cold Stream inlet Viscosity" |
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| 121 | ColdSide.Properties.Inlet.Mu = (1-InletCold.v)*PP.LiquidViscosity(InletCold.T,InletCold.P,xc)+ |
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| 122 | InletCold.v*PP.VapourViscosity(InletCold.T,InletCold.P,yc); |
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| 123 | |
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| 124 | "Cold Stream Outlet Viscosity" |
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| 125 | ColdSide.Properties.Outlet.Mu = (1-OutletCold.v)*PP.LiquidViscosity(OutletCold.T,OutletCold.P,OutletCold.x)+ |
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| 126 | OutletCold.v*PP.VapourViscosity(OutletCold.T,OutletCold.P,OutletCold.y); |
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| 127 | |
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| 128 | "Cold Stream Average Conductivity" |
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| 129 | ColdSide.Properties.Average.K = (1-InletCold.v)*PP.LiquidThermalConductivity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,xc)+ |
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| 130 | InletCold.v*PP.VapourThermalConductivity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,yc); |
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| 131 | |
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| 132 | "Cold Stream Inlet Conductivity" |
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| 133 | ColdSide.Properties.Inlet.K = (1-InletCold.v)*PP.LiquidThermalConductivity(InletCold.T,InletCold.P,xc)+ |
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| 134 | InletCold.v*PP.VapourThermalConductivity(InletCold.T,InletCold.P,yc); |
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| 135 | |
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| 136 | "Cold Stream Outlet Conductivity" |
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| 137 | ColdSide.Properties.Outlet.K = (1-OutletCold.v)*PP.LiquidThermalConductivity(OutletCold.T,OutletCold.P,OutletCold.x)+ |
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| 138 | OutletCold.v*PP.VapourThermalConductivity(OutletCold.T,OutletCold.P,OutletCold.y); |
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| 139 | |
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| 140 | "Cold Stream Viscosity at Wall Temperature" |
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| 141 | ColdSide.Properties.Wall.Mu = (1-InletCold.v)*PP.LiquidViscosity(ColdSide.Properties.Wall.Twall,ColdSide.Properties.Average.P,xc)+ |
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| 142 | InletCold.v*PP.VapourViscosity(ColdSide.Properties.Wall.Twall,ColdSide.Properties.Average.P,yc); |
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| 143 | |
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| 144 | "Hot Stream Average Heat Capacity" |
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| 145 | HotSide.Properties.Average.Cp = (1-InletHot.v)*PP.LiquidCp(HotSide.Properties.Average.T,HotSide.Properties.Average.P,xc) + |
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| 146 | InletHot.v*PP.VapourCp(HotSide.Properties.Average.T,HotSide.Properties.Average.P,yc); |
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| 147 | |
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| 148 | "Hot Stream Inlet Heat Capacity" |
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| 149 | HotSide.Properties.Inlet.Cp = (1-InletHot.v)*PP.LiquidCp(InletHot.T,InletHot.P,xc)+ |
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| 150 | InletHot.v*PP.VapourCp(InletHot.T,InletHot.P,yc); |
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| 151 | |
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| 152 | "Hot Stream Outlet Heat Capacity" |
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| 153 | HotSide.Properties.Outlet.Cp = (1-OutletHot.v)*PP.LiquidCp(OutletHot.T,OutletHot.P,OutletHot.x)+ |
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| 154 | OutletHot.v*PP.VapourCp(OutletHot.T,OutletHot.P,OutletHot.y); |
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| 155 | |
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| 156 | "Hot Stream Average Mass Density" |
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| 157 | HotSide.Properties.Average.rho = (1-InletHot.v)*PP.LiquidDensity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,xc)+ |
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| 158 | InletHot.v*PP.VapourDensity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,yc); |
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| 159 | |
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| 160 | "Hot Stream Inlet Mass Density" |
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| 161 | HotSide.Properties.Inlet.rho = (1-InletHot.v)*PP.LiquidDensity(InletHot.T,InletHot.P,xc)+ |
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| 162 | InletHot.v*PP.VapourDensity(InletHot.T,InletHot.P,yc); |
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| 163 | |
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| 164 | "Hot Stream Outlet Mass Density" |
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| 165 | HotSide.Properties.Outlet.rho = (1-OutletHot.v)*PP.LiquidDensity(OutletHot.T,OutletHot.P,OutletHot.x)+ |
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| 166 | OutletHot.v*PP.VapourDensity(OutletHot.T,OutletHot.P,OutletHot.y); |
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| 167 | |
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| 168 | "Hot Stream Average Viscosity" |
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| 169 | HotSide.Properties.Average.Mu = (1-InletHot.v)*PP.LiquidViscosity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,xc)+ |
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| 170 | InletHot.v*PP.VapourViscosity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,yc); |
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| 171 | |
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| 172 | "Hot Stream inlet Viscosity" |
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| 173 | HotSide.Properties.Inlet.Mu = (1-InletHot.v)*PP.LiquidViscosity(InletHot.T,InletHot.P,xc)+ |
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| 174 | InletHot.v*PP.VapourViscosity(InletHot.T,InletHot.P,yc); |
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| 175 | |
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| 176 | "Hot Stream Outlet Viscosity" |
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| 177 | HotSide.Properties.Outlet.Mu = (1-OutletHot.v)*PP.LiquidViscosity(OutletHot.T,OutletHot.P,OutletHot.x)+ |
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| 178 | OutletHot.v*PP.VapourViscosity(OutletHot.T,OutletHot.P,OutletHot.y); |
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| 179 | |
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| 180 | "Hot Stream Average Conductivity" |
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| 181 | HotSide.Properties.Average.K = (1-InletHot.v)*PP.LiquidThermalConductivity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,xc)+ |
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| 182 | InletHot.v*PP.VapourThermalConductivity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,yc); |
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| 183 | |
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| 184 | "Hot Stream Inlet Conductivity" |
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| 185 | HotSide.Properties.Inlet.K = (1-InletHot.v)*PP.LiquidThermalConductivity(InletHot.T,InletHot.P,xc)+ |
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| 186 | InletHot.v*PP.VapourThermalConductivity(InletHot.T,InletHot.P,yc); |
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| 187 | |
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| 188 | "Hot Stream Outlet Conductivity" |
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| 189 | HotSide.Properties.Outlet.K = (1-OutletHot.v)*PP.LiquidThermalConductivity(OutletHot.T,OutletHot.P,OutletHot.x)+ |
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| 190 | OutletHot.v*PP.VapourThermalConductivity(OutletHot.T,OutletHot.P,OutletHot.y); |
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| 191 | |
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| 192 | "Hot Stream Viscosity at Wall Temperature" |
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| 193 | HotSide.Properties.Wall.Mu = (1-InletHot.v)*PP.LiquidViscosity(HotSide.Properties.Wall.Twall,HotSide.Properties.Average.P,xc)+ |
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| 194 | InletHot.v*PP.VapourViscosity(HotSide.Properties.Wall.Twall,HotSide.Properties.Average.P,yc); |
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| 195 | |
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| 196 | "Energy Balance Hot Stream" |
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| 197 | Details.Q = InletHot.F*(InletHot.h-OutletHot.h); |
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| 198 | |
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| 199 | "Energy Balance Cold Stream" |
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| 200 | Details.Q =-InletCold.F*(InletCold.h-OutletCold.h); |
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| 201 | |
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| 202 | "Flow Mass Inlet Cold Stream" |
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| 203 | ColdSide.Properties.Inlet.Fw = sum(M*InletCold.z)*InletCold.F; |
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| 204 | |
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| 205 | "Flow Mass Outlet Cold Stream" |
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| 206 | ColdSide.Properties.Outlet.Fw = sum(M*OutletCold.z)*OutletCold.F; |
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| 207 | |
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| 208 | "Flow Mass Inlet Hot Stream" |
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| 209 | HotSide.Properties.Inlet.Fw = sum(M*InletHot.z)*InletHot.F; |
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| 210 | |
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| 211 | "Flow Mass Outlet Hot Stream" |
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| 212 | HotSide.Properties.Outlet.Fw = sum(M*OutletHot.z)*OutletHot.F; |
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| 213 | |
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| 214 | "Molar Balance Hot Stream" |
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| 215 | InletHot.F = OutletHot.F; |
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| 216 | |
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| 217 | "Molar Balance Cold Stream" |
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| 218 | InletCold.F = OutletCold.F; |
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| 219 | |
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| 220 | "Hot Stream Molar Fraction Constraint" |
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| 221 | OutletHot.z = InletHot.z; |
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| 222 | |
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| 223 | "Cold Stream Molar Fraction Constraint" |
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| 224 | OutletCold.z = InletCold.z; |
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| 225 | |
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| 226 | "Pressure Drop Hot Stream" |
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| 227 | OutletHot.P = InletHot.P - HotSide.PressureDrop.Pdrop; |
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| 228 | |
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| 229 | "Pressure Drop Cold Stream" |
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| 230 | OutletCold.P = InletCold.P - ColdSide.PressureDrop.Pdrop; |
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| 231 | |
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| 232 | "Fraction of Inlet Pressure : Hot Stream" |
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| 233 | HotSide.PressureDrop.Pdrop = InletHot.P*HotSide.PressureDrop.FPdrop; |
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| 234 | |
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| 235 | "Fraction of Inlet Pressure : Cold Stream" |
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| 236 | ColdSide.PressureDrop.Pdrop = InletCold.P*ColdSide.PressureDrop.FPdrop; |
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| 237 | |
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| 238 | end |
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| 239 | |
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| 240 | Model HeatExchanger_LMTD as HeatExchangerSimplified_Basic |
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| 241 | |
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| 242 | ATTRIBUTES |
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| 243 | Pallete = true; |
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| 244 | Brief = "Heat Exchanger Block - LMTD Method"; |
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| 245 | Info = |
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| 246 | "write some information"; |
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| 247 | |
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| 248 | PARAMETERS |
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| 249 | |
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| 250 | FlowDirection as Switcher (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent"); |
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| 251 | |
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| 252 | VARIABLES |
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| 253 | |
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| 254 | Method as LMTD_Basic (Brief="LMTD Method of Calculation"); |
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| 255 | |
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| 256 | EQUATIONS |
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| 257 | |
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| 258 | "Exchange Surface Area" |
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| 259 | Details.Q = Details.Ud*Details.A*Method.LMTD*Method.Fc; |
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| 260 | |
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| 261 | switch FlowDirection |
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| 262 | |
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| 263 | case "cocurrent": |
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| 264 | |
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| 265 | "Temperature Difference at Inlet" |
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| 266 | Method.DT0 = InletHot.T - InletCold.T; |
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| 267 | |
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| 268 | "Temperature Difference at Outlet" |
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| 269 | Method.DTL = OutletHot.T - OutletCold.T; |
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| 270 | |
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| 271 | case "counter": |
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| 272 | |
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| 273 | "Temperature Difference at Inlet" |
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| 274 | Method.DT0 = InletHot.T - OutletCold.T; |
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| 275 | |
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| 276 | "Temperature Difference at Outlet" |
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| 277 | Method.DTL = OutletHot.T - InletCold.T; |
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| 278 | |
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| 279 | end |
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| 280 | |
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| 281 | end |
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| 282 | |
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| 283 | Model Shell_and_Tubes_LMTD as HeatExchangerSimplified_Basic |
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| 284 | |
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| 285 | ATTRIBUTES |
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| 286 | Pallete = true; |
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| 287 | Brief = "Shell and Tubes Heat Exchanger with 1 or 2 shell pass - LMTD Method"; |
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| 288 | Info = |
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| 289 | "write some information"; |
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| 290 | |
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| 291 | PARAMETERS |
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| 292 | |
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| 293 | LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann"); |
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| 294 | ShellType as Switcher(Brief="TEMA Designation for Shell Type",Valid=["Eshell","Fshell"],Default="Eshell"); |
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| 295 | |
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| 296 | VARIABLES |
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| 297 | |
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| 298 | Method as LMTD_Basic (Brief="LMTD Method of Calculation"); |
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| 299 | R as positive (Brief=" Capacity Ratio for LMTD Correction Fator",Lower=1e-6); |
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| 300 | P as positive (Brief="Non - Dimensional Variable for LMTD Correction Fator ",Lower=1e-6); |
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| 301 | Pc as positive (Brief="Non - Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side",Lower=1e-6); |
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| 302 | Rho as positive (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6); |
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| 303 | Phi as positive (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6); |
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| 304 | lambdaN as Real (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation when 2 Pass Shell Side"); |
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| 305 | lambda1 as Real (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equationwhen 2 Pass Shell Side"); |
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| 306 | |
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| 307 | EQUATIONS |
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| 308 | |
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| 309 | "Exchange Surface Area" |
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| 310 | Details.Q = Details.Ud*Details.A*Method.LMTD*Method.Fc; |
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| 311 | |
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| 312 | "R: Capacity Ratio for LMTD Correction Fator" |
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| 313 | R*(OutletCold.T - InletCold.T ) = (InletHot.T-OutletHot.T); |
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| 314 | |
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| 315 | "P: Non - Dimensional Variable for LMTD Correction Fator" |
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| 316 | P*(InletHot.T- InletCold.T)= (OutletCold.T-InletCold.T); |
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| 317 | |
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| 318 | "Temperature Difference at Inlet" |
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| 319 | Method.DT0 = InletHot.T - OutletCold.T; |
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| 320 | |
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| 321 | "Temperature Difference at Outlet" |
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| 322 | Method.DTL = OutletHot.T - InletCold.T; |
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| 323 | |
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| 324 | switch ShellType |
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| 325 | |
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| 326 | case "Fshell": |
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| 327 | |
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| 328 | switch LMTDcorrection |
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| 329 | |
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| 330 | case "Bowmann": |
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| 331 | |
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| 332 | " Variable not in use with Bowmann equation" |
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| 333 | lambdaN =1; |
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| 334 | |
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| 335 | " Variable not in use with Bowmann equation" |
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| 336 | lambda1 =1; |
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| 337 | |
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| 338 | " Variable not in use with Bowmann equation" |
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| 339 | Phi = 1; |
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| 340 | |
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| 341 | " Variable not in use with Bowmann equation" |
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| 342 | Rho =1; |
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| 343 | |
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| 344 | if R equal 1 |
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| 345 | |
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| 346 | then |
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| 347 | |
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| 348 | "Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side" |
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| 349 | Pc*(2-P)= P; |
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| 350 | |
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| 351 | "LMTD Correction Fator when 2 Pass Shell Side" |
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| 352 | Method.Fc= (sqrt(2)*Pc)/((1-Pc)*ln( abs( ( 2-Pc*0.585786)/( 2-Pc*3.414214)))); |
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| 353 | |
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| 354 | else |
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| 355 | |
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| 356 | "Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side" |
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| 357 | Pc = (sqrt(abs(( 1-P*R)/(1-P)))-1)/(sqrt(abs(( 1-P*R)/(1-P)))-R); |
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| 358 | |
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| 359 | "LMTD Correction Fator when 2 Pass Shell Side" |
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| 360 | Method.Fc = sqrt(R*R+1)*ln(abs((1-Pc*R)/(1-Pc)))/((1-R)*ln( abs( ( 2-Pc*(R+1-sqrt(R*R+1)))/ ( 2-Pc*(R + 1 + sqrt(R*R+1)))))); |
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| 361 | |
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| 362 | end |
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| 363 | |
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| 364 | case "Fakeri": |
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| 365 | |
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| 366 | " Variable not in use with Fakeri equation" |
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| 367 | Pc = P; |
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| 368 | |
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| 369 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation" |
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| 370 | Rho*(1-P*R) = (1-P); |
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| 371 | |
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| 372 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation " |
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| 373 | Phi = (sqrt(((InletHot.T - OutletHot.T)*(InletHot.T- OutletHot.T))+((OutletCold.T - InletCold.T)*(OutletCold.T - InletCold.T))))/(2*((InletHot.T + OutletHot.T)-( InletCold.T + OutletCold.T))); |
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| 374 | |
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| 375 | if Rho equal 1 |
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| 376 | |
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| 377 | then |
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| 378 | |
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| 379 | " Variable not in use when Rho = 1" |
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| 380 | lambdaN = 1; |
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| 381 | |
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| 382 | " Variable not in use when Rho = 1" |
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| 383 | lambda1 = 1; |
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| 384 | |
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| 385 | "LMTD Correction Fator when 2 Pass Shell Side" |
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| 386 | Method.Fc = (2*Phi )/(ln(abs((1+Phi )/(1-Phi )))); |
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| 387 | |
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| 388 | else |
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| 389 | |
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| 390 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation" |
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| 391 | lambdaN = (1/ln(sqrt(abs(Rho))))*((2*sqrt(abs(Rho))-2)/(sqrt(abs(Rho))+1)); |
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| 392 | |
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| 393 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation" |
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| 394 | lambda1 = (1/ln(abs(Rho)))*((2*Rho-2)/(Rho+1)); |
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| 395 | |
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| 396 | "LMTD Correction Fator when 2 Pass Shell Side" |
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| 397 | Method.Fc = ((2*Phi *(lambdaN/lambda1))/(ln(abs((1+Phi *(lambdaN/lambda1))/(1-Phi *(lambdaN/lambda1))))))*(1/lambdaN); |
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| 398 | |
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| 399 | end |
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| 400 | |
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| 401 | |
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| 402 | end |
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| 403 | |
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| 404 | case "Eshell": |
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| 405 | |
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| 406 | " Variable not in use when 1 Pass Shell Side" |
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| 407 | lambdaN =1; |
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| 408 | |
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| 409 | " Variable not in use when 1 Pass Shell Side" |
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| 410 | lambda1 =1; |
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| 411 | |
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| 412 | " Variable not in use when 1 Pass Shell Side" |
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| 413 | Pc = P; |
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| 414 | |
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| 415 | switch LMTDcorrection |
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| 416 | |
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| 417 | case "Bowmann": |
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| 418 | |
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| 419 | " Variable not in use with Bowmann equation" |
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| 420 | Phi = 1; |
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| 421 | |
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| 422 | " Variable not in use with Bowmann equation" |
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| 423 | Rho = 1; |
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| 424 | |
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| 425 | |
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| 426 | if R equal 1 |
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| 427 | |
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| 428 | then |
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| 429 | |
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| 430 | "LMTD Correction Fator when 1 Pass Shell Side" |
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| 431 | Method.Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214)))); |
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| 432 | |
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| 433 | else |
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| 434 | |
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| 435 | "LMTD Correction Fator when 1 Pass Shell Side" |
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| 436 | Method.Fc = sqrt(R*R+1)*ln(abs((1-P*R)/(1-P)))/((1-R)*ln( abs( ( 2-P*(R+1-sqrt(R*R+1)))/ ( 2-P*(R + 1 + sqrt(R*R+1)))))); |
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| 437 | |
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| 438 | end |
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| 439 | |
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| 440 | case "Fakeri": |
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| 441 | |
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| 442 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation " |
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| 443 | Phi = (sqrt(((InletHot.T- OutletHot.T)*(InletHot.T- OutletHot.T))+((OutletCold.T - InletCold.T)*(OutletCold.T - InletCold.T))))/(2*((InletHot.T+ OutletHot.T)-(InletCold.T+ OutletCold.T))); |
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| 444 | |
|---|
| 445 | "Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation" |
|---|
| 446 | Rho*(1-P*R) = (1-P); |
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| 447 | |
|---|
| 448 | if Rho equal 1 |
|---|
| 449 | |
|---|
| 450 | then |
|---|
| 451 | |
|---|
| 452 | "LMTD Correction Fator when 1 Pass Shell Side" |
|---|
| 453 | Method.Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi)))); |
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| 454 | |
|---|
| 455 | else |
|---|
| 456 | |
|---|
| 457 | "LMTD Correction Fator when 1 Pass Shell Side" |
|---|
| 458 | Method.Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1)); |
|---|
| 459 | |
|---|
| 460 | end |
|---|
| 461 | |
|---|
| 462 | end |
|---|
| 463 | |
|---|
| 464 | |
|---|
| 465 | end |
|---|
| 466 | |
|---|
| 467 | end |
|---|
| 468 | |
|---|
| 469 | Model HeatExchanger_NTU as HeatExchangerSimplified_Basic |
|---|
| 470 | |
|---|
| 471 | ATTRIBUTES |
|---|
| 472 | Pallete = true; |
|---|
| 473 | Brief = "Heat Exchanger Block - NTU Method"; |
|---|
| 474 | Info = |
|---|
| 475 | "write some information"; |
|---|
| 476 | |
|---|
| 477 | PARAMETERS |
|---|
| 478 | |
|---|
| 479 | FlowDirection as Switcher (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent"); |
|---|
| 480 | |
|---|
| 481 | VARIABLES |
|---|
| 482 | |
|---|
| 483 | Method as NTU_Basic (Brief="NTU Method of Calculation"); |
|---|
| 484 | |
|---|
| 485 | EQUATIONS |
|---|
| 486 | |
|---|
| 487 | "Number of Units Transference" |
|---|
| 488 | Method.NTU*Method.Cmin = Details.Ud*Details.A; |
|---|
| 489 | |
|---|
| 490 | "Minimum Heat Capacity" |
|---|
| 491 | Method.Cmin = min([Method.Ch,Method.Cc]); |
|---|
| 492 | |
|---|
| 493 | "Maximum Heat Capacity" |
|---|
| 494 | Method.Cmax = max([Method.Ch,Method.Cc]); |
|---|
| 495 | |
|---|
| 496 | "Thermal Capacity Ratio" |
|---|
| 497 | Method.Cr = Method.Cmin/Method.Cmax; |
|---|
| 498 | |
|---|
| 499 | "Duty" |
|---|
| 500 | Details.Q = Method.Eft*Method.Cmin*(InletHot.T-InletCold.T); |
|---|
| 501 | |
|---|
| 502 | "Hot Stream Heat Capacity" |
|---|
| 503 | Method.Ch = InletHot.F*HotSide.Properties.Average.Cp; |
|---|
| 504 | |
|---|
| 505 | "Cold Stream Heat Capacity" |
|---|
| 506 | Method.Cc = InletCold.F*ColdSide.Properties.Average.Cp; |
|---|
| 507 | |
|---|
| 508 | "Effectiveness Correction" |
|---|
| 509 | Method.Eft1 = 1; |
|---|
| 510 | |
|---|
| 511 | if Method.Cr equal 0 |
|---|
| 512 | |
|---|
| 513 | then |
|---|
| 514 | |
|---|
| 515 | "Effectiveness" |
|---|
| 516 | Method.Eft = 1-exp(-Method.NTU); |
|---|
| 517 | |
|---|
| 518 | else |
|---|
| 519 | |
|---|
| 520 | switch FlowDirection |
|---|
| 521 | |
|---|
| 522 | case "cocurrent": |
|---|
| 523 | |
|---|
| 524 | "Effectiveness in Cocurrent Flow" |
|---|
| 525 | Method.Eft = (1-exp(-Method.NTU*(1+Method.Cr)))/(1+Method.Cr); |
|---|
| 526 | |
|---|
| 527 | case "counter": |
|---|
| 528 | |
|---|
| 529 | if Method.Cr equal 1 |
|---|
| 530 | |
|---|
| 531 | then |
|---|
| 532 | "Effectiveness in Counter Flow" |
|---|
| 533 | Method.Eft = Method.NTU/(1+Method.NTU); |
|---|
| 534 | |
|---|
| 535 | else |
|---|
| 536 | "Effectiveness in Counter Flow" |
|---|
| 537 | Method.Eft = (1-exp(-Method.NTU*(1-Method.Cr)))/(1-Method.Cr*exp(-Method.NTU*(1-Method.Cr))); |
|---|
| 538 | |
|---|
| 539 | end |
|---|
| 540 | |
|---|
| 541 | end |
|---|
| 542 | |
|---|
| 543 | |
|---|
| 544 | end |
|---|
| 545 | |
|---|
| 546 | end |
|---|
| 547 | |
|---|
| 548 | Model Shell_and_Tubes_NTU as HeatExchangerSimplified_Basic |
|---|
| 549 | |
|---|
| 550 | ATTRIBUTES |
|---|
| 551 | Pallete = true; |
|---|
| 552 | Brief = "Shell and Tubes Heat Exchanger with 1 or 2 shell pass - NTU Method"; |
|---|
| 553 | Info = |
|---|
| 554 | "write some information"; |
|---|
| 555 | |
|---|
| 556 | PARAMETERS |
|---|
| 557 | |
|---|
| 558 | ShellType as Switcher (Brief="TEMA Designation",Valid=["Eshell","Fshell"],Default="Eshell"); |
|---|
| 559 | |
|---|
| 560 | VARIABLES |
|---|
| 561 | |
|---|
| 562 | Method as NTU_Basic (Brief="NTU Method of Calculation"); |
|---|
| 563 | |
|---|
| 564 | EQUATIONS |
|---|
| 565 | |
|---|
| 566 | "Number of Units Transference" |
|---|
| 567 | Method.NTU*Method.Cmin = Details.Ud*Details.A; |
|---|
| 568 | |
|---|
| 569 | "Minimum Heat Capacity" |
|---|
| 570 | Method.Cmin = min([Method.Ch,Method.Cc]); |
|---|
| 571 | |
|---|
| 572 | "Maximum Heat Capacity" |
|---|
| 573 | Method.Cmax = max([Method.Ch,Method.Cc]); |
|---|
| 574 | |
|---|
| 575 | "Thermal Capacity Ratio" |
|---|
| 576 | Method.Cr = Method.Cmin/Method.Cmax; |
|---|
| 577 | |
|---|
| 578 | "Duty" |
|---|
| 579 | Details.Q = Method.Eft*Method.Cmin*(InletHot.T-InletCold.T); |
|---|
| 580 | |
|---|
| 581 | "Hot Stream Heat Capacity" |
|---|
| 582 | Method.Ch = InletHot.F*HotSide.Properties.Average.Cp; |
|---|
| 583 | |
|---|
| 584 | "Cold Stream Heat Capacity" |
|---|
| 585 | Method.Cc = InletCold.F*ColdSide.Properties.Average.Cp; |
|---|
| 586 | |
|---|
| 587 | switch ShellType |
|---|
| 588 | |
|---|
| 589 | case "Fshell": |
|---|
| 590 | |
|---|
| 591 | "Effectiveness Correction for 2 pass shell side" |
|---|
| 592 | Method.Eft1 = 2*(1+Method.Cr+sqrt(1+Method.Cr^2)*((1+exp(-Method.NTU*sqrt(1+Method.Cr^2)))/(1-exp(-Method.NTU*sqrt(1+Method.Cr^2)))) )^-1; |
|---|
| 593 | |
|---|
| 594 | "TEMA F Shell Effectiveness" |
|---|
| 595 | Method.Eft = ( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 -1 )*( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 - Method.Cr )^-1; |
|---|
| 596 | |
|---|
| 597 | case "Eshell": |
|---|
| 598 | |
|---|
| 599 | "TEMA E Shell Effectiveness" |
|---|
| 600 | Method.Eft = 2*(1+Method.Cr+sqrt(1+Method.Cr^2)*((1+exp(-Method.NTU*sqrt(1+Method.Cr^2)))/(1-exp(-Method.NTU*sqrt(1+Method.Cr^2)))) )^-1; |
|---|
| 601 | |
|---|
| 602 | "Variable not in use when 1 Pass Shell Side" |
|---|
| 603 | Method.Eft1 = 1; |
|---|
| 604 | |
|---|
| 605 | end |
|---|
| 606 | |
|---|
| 607 | end |
|---|
