[284] | 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 | * Author: Gerson Balbueno Bicca |
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| 16 | * $Id: DoublePipe.mso 284 2007-06-16 22:23:13Z bicca $ |
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| 17 | *------------------------------------------------------------------*# |
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| 18 | |
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| 19 | using "HEX_Engine"; |
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| 20 | |
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| 21 | Model DoublePipe_Basic |
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| 22 | |
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| 23 | ATTRIBUTES |
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| 24 | Pallete = false; |
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| 25 | Brief = "Basic Equations for rigorous double pipe heat exchanger model."; |
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| 26 | Info = |
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| 27 | "to be documented."; |
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| 28 | |
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| 29 | PARAMETERS |
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| 30 | |
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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 | HotSide as Switcher (Brief="Flag for Fluid Alocation ",Valid=["outer","inner"],Default="outer"); |
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| 37 | innerFlowRegime as Switcher (Brief="Inner Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar"); |
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| 38 | outerFlowRegime as Switcher (Brief="Outer Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar"); |
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| 39 | |
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| 40 | InnerLaminarCorrelation as Switcher (Brief="Heat Transfer Correlation in Laminar Flow for the Inner Side",Valid=["Hausen","Schlunder"],Default="Hausen"); |
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| 41 | InnerTransitionCorrelation as Switcher (Brief="Heat Transfer Correlation in Transition Flow for the Inner Side",Valid=["Gnielinski","ESDU"],Default="Gnielinski"); |
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| 42 | InnerTurbulentCorrelation as Switcher (Brief="Heat Transfer Correlation in Turbulent Flow for the Inner Side",Valid=["Petukhov","SiederTate"],Default="Petukhov"); |
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| 43 | |
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| 44 | OuterLaminarCorrelation as Switcher (Brief="Heat Transfer Correlation in Laminar Flow for the Outer Side",Valid=["Hausen","Schlunder"],Default="Hausen"); |
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| 45 | OuterTransitionCorrelation as Switcher (Brief="Heat Transfer Correlation in Transition Flow for the OuterSide",Valid=["Gnielinski","ESDU"],Default="Gnielinski"); |
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| 46 | OuterTurbulentCorrelation as Switcher (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov"); |
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| 47 | |
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| 48 | Pi as constant (Brief="Pi Number",Default=3.14159265); |
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| 49 | DoInner as length (Brief="Outside Diameter of Inner Pipe",Lower=1e-6); |
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| 50 | DiInner as length (Brief="Inside Diameter of Inner Pipe",Lower=1e-10); |
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| 51 | DiOuter as length (Brief="Inside Diameter of Outer pipe",Lower=1e-10); |
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| 52 | Lpipe as length (Brief="Effective Tube Length",Lower=0.1); |
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| 53 | Kwall as conductivity (Brief="Tube Wall Material Thermal Conductivity",Default=1.0); |
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| 54 | Rfi as positive (Brief="Inside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0); |
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| 55 | Rfo as positive (Brief="Outside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0); |
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| 56 | |
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| 57 | VARIABLES |
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| 58 | |
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| 59 | in InletInner as stream (Brief="Inlet Inner Stream"); |
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| 60 | in InletOuter as stream (Brief="Inlet Outer Stream"); |
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| 61 | out OutletInner as streamPH (Brief="Outlet Inner Stream"); |
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| 62 | out OutletOuter as streamPH (Brief="Outlet Outer Stream"); |
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| 63 | |
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| 64 | Details as Details_Main (Brief="Some Details in the Heat Exchanger"); |
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| 65 | Inner as Main_DoublePipe (Brief="Inner Side of the Heat Exchanger"); |
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| 66 | Outer as Main_DoublePipe (Brief="Outer Side of the Heat Exchanger"); |
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| 67 | |
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| 68 | SET |
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| 69 | |
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| 70 | #"Component Molecular Weight" |
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| 71 | M = PP.MolecularWeight(); |
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| 72 | |
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| 73 | #"Pi Number" |
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| 74 | Pi = 3.14159265; |
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| 75 | |
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| 76 | #"Inner Pipe Cross Sectional Area for Flow" |
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| 77 | Inner.HeatTransfer.As=Pi*DiInner*DiInner/4; |
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| 78 | |
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| 79 | #"Outer Pipe Cross Sectional Area for Flow" |
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| 80 | Outer.HeatTransfer.As=Pi*(DiOuter*DiOuter - DoInner*DoInner)/4; |
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| 81 | |
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| 82 | #"Inner Pipe Hydraulic Diameter for Heat Transfer" |
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| 83 | Inner.HeatTransfer.Dh=DiInner; |
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| 84 | |
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| 85 | #"Outer Pipe Hydraulic Diameter for Heat Transfer" |
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| 86 | Outer.HeatTransfer.Dh=(DiOuter*DiOuter-DoInner*DoInner)/DoInner; |
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| 87 | |
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| 88 | #"Inner Pipe Hydraulic Diameter for Pressure Drop" |
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| 89 | Inner.PressureDrop.Dh=DiInner; |
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| 90 | |
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| 91 | #"Outer Pipe Hydraulic Diameter for Pressure Drop" |
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| 92 | Outer.PressureDrop.Dh=DiOuter-DoInner; |
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| 93 | |
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| 94 | EQUATIONS |
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| 95 | |
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| 96 | "Outer Stream Average Temperature" |
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| 97 | Outer.Properties.Average.T = 0.5*InletOuter.T + 0.5*OutletOuter.T; |
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| 98 | |
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| 99 | "Inner Stream Average Temperature" |
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| 100 | Inner.Properties.Average.T = 0.5*InletInner.T + 0.5*OutletInner.T; |
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| 101 | |
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| 102 | "Outer Stream Average Pressure" |
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| 103 | Outer.Properties.Average.P = 0.5*InletOuter.P+0.5*OutletOuter.P; |
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| 104 | |
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| 105 | "Inner Stream Average Pressure" |
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| 106 | Inner.Properties.Average.P = 0.5*InletInner.P+0.5*OutletInner.P; |
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| 107 | |
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| 108 | "Inner Stream Wall Temperature" |
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| 109 | Inner.Properties.Wall.Twall = 0.5*Outer.Properties.Average.T + 0.5*Inner.Properties.Average.T; |
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| 110 | |
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| 111 | "Outer Stream Wall Temperature" |
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| 112 | Outer.Properties.Wall.Twall = 0.5*Outer.Properties.Average.T + 0.5*Inner.Properties.Average.T; |
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| 113 | |
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| 114 | "Outer Stream Average Molecular Weight" |
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| 115 | Outer.Properties.Average.Mw = sum(M*InletOuter.z); |
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| 116 | |
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| 117 | "Inner Stream Average Molecular Weight" |
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| 118 | Inner.Properties.Average.Mw = sum(M*InletInner.z); |
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| 119 | |
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| 120 | if InletInner.v equal 0 |
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| 121 | |
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| 122 | then |
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| 123 | |
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| 124 | "Average Heat Capacity Inner Stream" |
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| 125 | Inner.Properties.Average.Cp = PP.LiquidCp(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 126 | |
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| 127 | "Inlet Heat Capacity Inner Stream" |
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| 128 | Inner.Properties.Inlet.Cp = PP.LiquidCp(InletInner.T,InletInner.P,InletInner.z); |
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| 129 | |
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| 130 | "Outlet Heat Capacity Inner Stream" |
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| 131 | Inner.Properties.Outlet.Cp = PP.LiquidCp(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 132 | |
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| 133 | "Average Mass Density Inner Stream" |
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| 134 | Inner.Properties.Average.rho = PP.LiquidDensity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 135 | |
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| 136 | "Inlet Mass Density Inner Stream" |
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| 137 | Inner.Properties.Inlet.rho = PP.LiquidDensity(InletInner.T,InletInner.P,InletInner.z); |
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| 138 | |
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| 139 | "Outlet Mass Density Inner Stream" |
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| 140 | Inner.Properties.Outlet.rho = PP.LiquidDensity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 141 | |
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| 142 | "Average Viscosity Inner Stream" |
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| 143 | Inner.Properties.Average.Mu = PP.LiquidViscosity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 144 | |
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| 145 | "Inlet Viscosity Inner Stream" |
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| 146 | Inner.Properties.Inlet.Mu = PP.LiquidViscosity(InletInner.T,InletInner.P,InletInner.z); |
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| 147 | |
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| 148 | "Outlet Viscosity Inner Stream" |
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| 149 | Inner.Properties.Outlet.Mu = PP.LiquidViscosity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 150 | |
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| 151 | "Average Conductivity Inner Stream" |
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| 152 | Inner.Properties.Average.K = PP.LiquidThermalConductivity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 153 | |
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| 154 | "Inlet Conductivity Inner Stream" |
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| 155 | Inner.Properties.Inlet.K = PP.LiquidThermalConductivity(InletInner.T,InletInner.P,InletInner.z); |
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| 156 | |
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| 157 | "Outlet Conductivity Inner Stream" |
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| 158 | Inner.Properties.Outlet.K = PP.LiquidThermalConductivity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 159 | |
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| 160 | "Viscosity Inner Stream at wall temperature" |
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| 161 | Inner.Properties.Wall.Mu = PP.LiquidViscosity(Inner.Properties.Wall.Twall,Inner.Properties.Average.P,InletInner.z); |
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| 162 | |
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| 163 | else |
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| 164 | |
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| 165 | "Average Heat Capacity InnerStream" |
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| 166 | Inner.Properties.Average.Cp = PP.VapourCp(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 167 | |
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| 168 | "Inlet Heat Capacity Inner Stream" |
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| 169 | Inner.Properties.Inlet.Cp = PP.VapourCp(InletInner.T,InletInner.P,InletInner.z); |
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| 170 | |
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| 171 | "Outlet Heat Capacity Inner Stream" |
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| 172 | Inner.Properties.Outlet.Cp = PP.VapourCp(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 173 | |
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| 174 | "Average Mass Density Inner Stream" |
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| 175 | Inner.Properties.Average.rho = PP.VapourDensity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 176 | |
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| 177 | "Inlet Mass Density Inner Stream" |
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| 178 | Inner.Properties.Inlet.rho = PP.VapourDensity(InletInner.T,InletInner.P,InletInner.z); |
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| 179 | |
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| 180 | "Outlet Mass Density Inner Stream" |
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| 181 | Inner.Properties.Outlet.rho = PP.VapourDensity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 182 | |
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| 183 | "Average Viscosity Inner Stream" |
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| 184 | Inner.Properties.Average.Mu = PP.VapourViscosity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 185 | |
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| 186 | "Inlet Viscosity Inner Stream" |
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| 187 | Inner.Properties.Inlet.Mu = PP.VapourViscosity(InletInner.T,InletInner.P,InletInner.z); |
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| 188 | |
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| 189 | "Outlet Viscosity Inner Stream" |
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| 190 | Inner.Properties.Outlet.Mu = PP.VapourViscosity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 191 | |
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| 192 | "Average Conductivity Inner Stream" |
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| 193 | Inner.Properties.Average.K = PP.VapourThermalConductivity(Inner.Properties.Average.T,Inner.Properties.Average.P,InletInner.z); |
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| 194 | |
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| 195 | "Inlet Conductivity Inner Stream" |
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| 196 | Inner.Properties.Inlet.K = PP.VapourThermalConductivity(InletInner.T,InletInner.P,InletInner.z); |
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| 197 | |
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| 198 | "Outlet Conductivity Inner Stream" |
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| 199 | Inner.Properties.Outlet.K = PP.VapourThermalConductivity(OutletInner.T,OutletInner.P,OutletInner.z); |
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| 200 | |
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| 201 | "Viscosity Inner Stream at wall temperature" |
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| 202 | Inner.Properties.Wall.Mu = PP.VapourViscosity(Inner.Properties.Wall.Twall,Inner.Properties.Average.P,InletInner.z); |
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| 203 | |
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| 204 | end |
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| 205 | |
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| 206 | if InletOuter.v equal 0 |
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| 207 | |
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| 208 | then |
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| 209 | |
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| 210 | "Average Heat Capacity Outer Stream" |
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| 211 | Outer.Properties.Average.Cp = PP.LiquidCp(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 212 | |
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| 213 | "Inlet Heat Capacity Outer Stream" |
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| 214 | Outer.Properties.Inlet.Cp = PP.LiquidCp(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 215 | |
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| 216 | "Outlet Heat Capacity Outer Stream" |
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| 217 | Outer.Properties.Outlet.Cp = PP.LiquidCp(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 218 | |
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| 219 | "Average Mass Density Outer Stream" |
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| 220 | Outer.Properties.Average.rho = PP.LiquidDensity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 221 | |
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| 222 | "Inlet Mass Density Outer Stream" |
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| 223 | Outer.Properties.Inlet.rho = PP.LiquidDensity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 224 | |
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| 225 | "Outlet Mass Density Outer Stream" |
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| 226 | Outer.Properties.Outlet.rho = PP.LiquidDensity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 227 | |
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| 228 | "Average Viscosity Outer Stream" |
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| 229 | Outer.Properties.Average.Mu = PP.LiquidViscosity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 230 | |
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| 231 | "Inlet Viscosity Outer Stream" |
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| 232 | Outer.Properties.Inlet.Mu = PP.LiquidViscosity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 233 | |
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| 234 | "Outlet Viscosity Outer Stream" |
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| 235 | Outer.Properties.Outlet.Mu = PP.LiquidViscosity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 236 | |
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| 237 | "Average Conductivity Outer Stream" |
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| 238 | Outer.Properties.Average.K = PP.LiquidThermalConductivity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 239 | |
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| 240 | "Inlet Conductivity Outer Stream" |
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| 241 | Outer.Properties.Inlet.K = PP.LiquidThermalConductivity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 242 | |
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| 243 | "Outlet Conductivity Outer Stream" |
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| 244 | Outer.Properties.Outlet.K = PP.LiquidThermalConductivity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 245 | |
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| 246 | "Viscosity Outer Stream at wall temperature" |
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| 247 | Outer.Properties.Wall.Mu = PP.LiquidViscosity(Outer.Properties.Wall.Twall,Outer.Properties.Average.P,InletOuter.z); |
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| 248 | |
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| 249 | |
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| 250 | else |
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| 251 | |
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| 252 | "Average Heat Capacity Outer Stream" |
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| 253 | Outer.Properties.Average.Cp = PP.VapourCp(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 254 | |
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| 255 | "Inlet Heat Capacity Outer Stream" |
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| 256 | Outer.Properties.Inlet.Cp = PP.VapourCp(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 257 | |
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| 258 | "Outlet Heat Capacity Outer Stream" |
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| 259 | Outer.Properties.Outlet.Cp = PP.VapourCp(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 260 | |
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| 261 | "Average Mass Density Outer Stream" |
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| 262 | Outer.Properties.Average.rho = PP.VapourDensity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 263 | |
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| 264 | "Inlet Mass Density Outer Stream" |
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| 265 | Outer.Properties.Inlet.rho = PP.VapourDensity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 266 | |
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| 267 | "Outlet Mass Density Outer Stream" |
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| 268 | Outer.Properties.Outlet.rho = PP.VapourDensity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 269 | |
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| 270 | "Average Viscosity Outer Stream" |
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| 271 | Outer.Properties.Average.Mu = PP.VapourViscosity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 272 | |
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| 273 | "Inlet Viscosity Outer Stream" |
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| 274 | Outer.Properties.Inlet.Mu = PP.VapourViscosity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 275 | |
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| 276 | "Outlet Viscosity Outer Stream" |
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| 277 | Outer.Properties.Outlet.Mu = PP.VapourViscosity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 278 | |
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| 279 | "Average Conductivity Outer Stream" |
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| 280 | Outer.Properties.Average.K = PP.VapourThermalConductivity(Outer.Properties.Average.T,Outer.Properties.Average.P,InletOuter.z); |
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| 281 | |
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| 282 | "Inlet Conductivity Outer Stream" |
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| 283 | Outer.Properties.Inlet.K = PP.VapourThermalConductivity(InletOuter.T,InletOuter.P,InletOuter.z); |
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| 284 | |
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| 285 | "Outlet Conductivity Outer Stream" |
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| 286 | Outer.Properties.Outlet.K = PP.VapourThermalConductivity(OutletOuter.T,OutletOuter.P,OutletOuter.z); |
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| 287 | |
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| 288 | "Viscosity Outer Stream at wall temperature" |
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| 289 | Outer.Properties.Wall.Mu = PP.VapourViscosity(Outer.Properties.Wall.Twall,Outer.Properties.Average.P,InletOuter.z); |
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| 290 | |
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| 291 | end |
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| 292 | |
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| 293 | switch HotSide |
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| 294 | |
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| 295 | case "outer": |
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| 296 | |
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| 297 | "Energy Balance Hot Stream" |
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| 298 | Details.Q = InletOuter.F*(InletOuter.h-OutletOuter.h); |
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| 299 | |
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| 300 | "Energy Balance Cold Stream" |
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| 301 | Details.Q = InletInner.F*(OutletInner.h - InletInner.h); |
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| 302 | |
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| 303 | when InletInner.T > InletOuter.T switchto "inner"; |
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| 304 | |
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| 305 | case "inner": |
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| 306 | |
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| 307 | "Energy Balance Hot Stream" |
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| 308 | Details.Q = InletInner.F*(InletInner.h-OutletInner.h); |
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| 309 | |
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| 310 | "Energy Balance Cold Stream" |
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| 311 | Details.Q = InletOuter.F*(OutletOuter.h - InletOuter.h); |
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| 312 | |
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| 313 | when InletInner.T < InletOuter.T switchto "outer"; |
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| 314 | |
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| 315 | end |
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| 316 | |
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| 317 | "Flow Mass Inlet Inner Stream" |
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| 318 | Inner.Properties.Inlet.Fw = sum(M*InletInner.z)*InletInner.F; |
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| 319 | |
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| 320 | "Flow Mass Outlet Inner Stream" |
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| 321 | Inner.Properties.Outlet.Fw = sum(M*OutletInner.z)*OutletInner.F; |
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| 322 | |
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| 323 | "Flow Mass Inlet Outer Stream" |
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| 324 | Outer.Properties.Inlet.Fw = sum(M*InletOuter.z)*InletOuter.F; |
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| 325 | |
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| 326 | "Flow Mass Outlet Outer Stream" |
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| 327 | Outer.Properties.Outlet.Fw = sum(M*OutletOuter.z)*OutletOuter.F; |
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| 328 | |
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| 329 | "Molar Balance Outer Stream" |
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| 330 | OutletOuter.F = InletOuter.F; |
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| 331 | |
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| 332 | "Molar Balance Inner Stream" |
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| 333 | OutletInner.F = InletInner.F; |
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| 334 | |
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| 335 | "Outer Stream Molar Fraction Constraint" |
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| 336 | OutletOuter.z=InletOuter.z; |
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| 337 | |
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| 338 | "InnerStream Molar Fraction Constraint" |
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| 339 | OutletInner.z=InletInner.z; |
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| 340 | |
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| 341 | "Exchange Surface Area" |
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| 342 | Details.A=Pi*DoInner*Lpipe; |
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| 343 | |
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| 344 | switch innerFlowRegime |
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| 345 | |
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| 346 | case "laminar": |
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| 347 | |
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| 348 | "Inner Side Friction Factor for Pressure Drop - laminar Flow" |
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| 349 | Inner.PressureDrop.fi*Inner.PressureDrop.Re = 16; |
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| 350 | |
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| 351 | when Inner.PressureDrop.Re > 2300 switchto "transition"; |
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| 352 | |
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| 353 | case "transition": |
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| 354 | |
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| 355 | "using Turbulent Flow - to be implemented" |
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| 356 | (Inner.PressureDrop.fi-0.0035)*(Inner.PressureDrop.Re^0.42) = 0.264; |
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| 357 | |
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| 358 | when Inner.PressureDrop.Re < 2300 switchto "laminar"; |
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| 359 | when Inner.PressureDrop.Re > 10000 switchto "turbulent"; |
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| 360 | |
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| 361 | case "turbulent": |
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| 362 | |
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| 363 | "Inner Side Friction Factor - Turbulent Flow" |
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| 364 | (Inner.PressureDrop.fi-0.0035)*(Inner.PressureDrop.Re^0.42) = 0.264; |
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| 365 | |
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| 366 | when Inner.PressureDrop.Re < 10000 switchto "transition"; |
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| 367 | |
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| 368 | end |
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| 369 | |
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| 370 | switch outerFlowRegime |
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| 371 | |
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| 372 | case "laminar": |
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| 373 | |
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| 374 | "Outer Side Friction Factor - laminar Flow" |
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| 375 | Outer.PressureDrop.fi*Outer.PressureDrop.Re = 16; |
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| 376 | |
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| 377 | when Outer.PressureDrop.Re > 2300 switchto "transition"; |
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| 378 | |
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| 379 | case "transition": |
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| 380 | |
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| 381 | "using Turbulent Flow - Transition Flow must be implemented" |
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| 382 | (Outer.PressureDrop.fi-0.0035)*(Outer.PressureDrop.Re^0.42) = 0.264; |
---|
| 383 | |
---|
| 384 | when Outer.PressureDrop.Re < 2300 switchto "laminar"; |
---|
| 385 | when Outer.PressureDrop.Re > 10000 switchto "turbulent"; |
---|
| 386 | |
---|
| 387 | case "turbulent": |
---|
| 388 | |
---|
| 389 | "Outer Side Friction Factor - Turbulent Flow" |
---|
| 390 | (Outer.PressureDrop.fi-0.0035)*(Outer.PressureDrop.Re^0.42) = 0.264; |
---|
| 391 | |
---|
| 392 | when Outer.PressureDrop.Re < 10000 switchto "transition"; |
---|
| 393 | |
---|
| 394 | end |
---|
| 395 | |
---|
| 396 | switch innerFlowRegime |
---|
| 397 | |
---|
| 398 | case "laminar": |
---|
| 399 | |
---|
| 400 | "Inner Side Friction Factor for Heat Transfer - laminar Flow" |
---|
| 401 | Inner.HeatTransfer.fi = 1/(0.79*ln(Inner.HeatTransfer.Re)-1.64)^2; |
---|
| 402 | |
---|
| 403 | switch InnerLaminarCorrelation |
---|
| 404 | |
---|
| 405 | case "Hausen": |
---|
| 406 | |
---|
| 407 | "Nusselt Number" |
---|
| 408 | Inner.HeatTransfer.Nu = 3.665 + ((0.19*((DiInner/Lpipe)*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR)^0.8)/(1+0.117*((DiInner/Lpipe)*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR)^0.467)); |
---|
| 409 | |
---|
| 410 | case "Schlunder": |
---|
| 411 | |
---|
| 412 | "Nusselt Number" |
---|
| 413 | Inner.HeatTransfer.Nu = (49.027896+4.173281*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR*(DiInner/Lpipe))^(1/3); |
---|
| 414 | |
---|
| 415 | end |
---|
| 416 | |
---|
| 417 | when Inner.HeatTransfer.Re > 2300 switchto "transition"; |
---|
| 418 | |
---|
| 419 | case "transition": |
---|
| 420 | |
---|
| 421 | "Inner Side Friction Factor for Heat Transfer - transition Flow" |
---|
| 422 | Inner.HeatTransfer.fi = 1/(0.79*ln(Inner.HeatTransfer.Re)-1.64)^2; |
---|
| 423 | |
---|
| 424 | switch InnerTransitionCorrelation |
---|
| 425 | |
---|
| 426 | case "Gnielinski": |
---|
| 427 | |
---|
| 428 | "Nusselt Number" |
---|
| 429 | Inner.HeatTransfer.Nu*(1+(12.7*sqrt(0.125*Inner.HeatTransfer.fi)*((Inner.HeatTransfer.PR)^(2/3) -1))) = 0.125*Inner.HeatTransfer.fi*(Inner.HeatTransfer.Re-1000)*Inner.HeatTransfer.PR; |
---|
| 430 | |
---|
| 431 | case "ESDU": |
---|
| 432 | |
---|
| 433 | "Nusselt Number" |
---|
| 434 | Inner.HeatTransfer.Nu =1;#to be implemented |
---|
| 435 | |
---|
| 436 | end |
---|
| 437 | |
---|
| 438 | when Inner.HeatTransfer.Re < 2300 switchto "laminar"; |
---|
| 439 | when Inner.HeatTransfer.Re > 10000 switchto "turbulent"; |
---|
| 440 | |
---|
| 441 | case "turbulent": |
---|
| 442 | |
---|
| 443 | switch InnerTurbulentCorrelation |
---|
| 444 | |
---|
| 445 | case "Petukhov": |
---|
| 446 | |
---|
| 447 | "Inner Side Friction Factor for Heat Transfer - turbulent Flow" |
---|
| 448 | Inner.HeatTransfer.fi = 1/(1.82*log(Inner.HeatTransfer.Re)-1.64)^2; |
---|
| 449 | |
---|
| 450 | "Nusselt Number" |
---|
| 451 | Inner.HeatTransfer.Nu*(1.07+(12.7*sqrt(0.125*Inner.HeatTransfer.fi)*((Inner.HeatTransfer.PR)^(2/3) -1))) = 0.125*Inner.HeatTransfer.fi*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR; |
---|
| 452 | |
---|
| 453 | case "SiederTate": |
---|
| 454 | |
---|
| 455 | "Nusselt Number" |
---|
| 456 | Inner.HeatTransfer.Nu = 0.027*(Inner.HeatTransfer.PR)^(1/3)*(Inner.HeatTransfer.Re)^(4/5); |
---|
| 457 | |
---|
| 458 | "Inner Side Friction Factor for Heat Transfer - turbulent Flow" |
---|
| 459 | Inner.HeatTransfer.fi = 1/(1.82*log(Inner.HeatTransfer.Re)-1.64)^2; |
---|
| 460 | |
---|
| 461 | end |
---|
| 462 | |
---|
| 463 | when Inner.HeatTransfer.Re < 10000 switchto "transition"; |
---|
| 464 | |
---|
| 465 | end |
---|
| 466 | |
---|
| 467 | switch outerFlowRegime |
---|
| 468 | |
---|
| 469 | case "laminar": |
---|
| 470 | |
---|
| 471 | "Outer Side Friction Factor for Heat Transfer - laminar Flow" |
---|
| 472 | Outer.HeatTransfer.fi = 1/(0.79*ln(Outer.HeatTransfer.Re)-1.64)^2; |
---|
| 473 | |
---|
| 474 | switch OuterLaminarCorrelation |
---|
| 475 | |
---|
| 476 | case "Hausen": |
---|
| 477 | |
---|
| 478 | "Nusselt Number" |
---|
| 479 | Outer.HeatTransfer.Nu = 3.665 + ((0.19*((Outer.HeatTransfer.Dh/Lpipe)*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR)^0.8)/(1+0.117*((Outer.HeatTransfer.Dh/Lpipe)*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR)^0.467)); |
---|
| 480 | |
---|
| 481 | case "Schlunder": |
---|
| 482 | |
---|
| 483 | "Nusselt Number" |
---|
| 484 | Outer.HeatTransfer.Nu = (49.027896+4.173281*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR*(Outer.HeatTransfer.Dh/Lpipe))^(1/3); |
---|
| 485 | |
---|
| 486 | end |
---|
| 487 | |
---|
| 488 | when Outer.HeatTransfer.Re > 2300 switchto "transition"; |
---|
| 489 | |
---|
| 490 | case "transition": |
---|
| 491 | |
---|
| 492 | switch OuterTransitionCorrelation |
---|
| 493 | |
---|
| 494 | case "Gnielinski": |
---|
| 495 | |
---|
| 496 | "Outer Side Friction Factor for Heat Transfer - transition Flow" |
---|
| 497 | Outer.HeatTransfer.fi = 1/(0.79*ln(Outer.HeatTransfer.Re)-1.64)^2; |
---|
| 498 | |
---|
| 499 | "Nusselt Number" |
---|
| 500 | Outer.HeatTransfer.Nu*(1+(12.7*sqrt(0.125*Outer.HeatTransfer.fi)*((Outer.HeatTransfer.PR)^(2/3) -1))) = 0.125*Outer.HeatTransfer.fi*(Outer.HeatTransfer.Re-1000)*Outer.HeatTransfer.PR; |
---|
| 501 | |
---|
| 502 | case "ESDU": |
---|
| 503 | |
---|
| 504 | "Nusselt Number" |
---|
| 505 | Outer.HeatTransfer.Nu =1;#to be implemented |
---|
| 506 | |
---|
| 507 | "Outer Side Friction Factor for Heat Transfer - transition Flow" |
---|
| 508 | Outer.HeatTransfer.fi = 1/(0.79*ln(Outer.HeatTransfer.Re)-1.64)^2; |
---|
| 509 | |
---|
| 510 | end |
---|
| 511 | |
---|
| 512 | when Outer.HeatTransfer.Re < 2300 switchto "laminar"; |
---|
| 513 | when Outer.HeatTransfer.Re > 10000 switchto "turbulent"; |
---|
| 514 | |
---|
| 515 | case "turbulent": |
---|
| 516 | |
---|
| 517 | switch OuterTurbulentCorrelation |
---|
| 518 | |
---|
| 519 | case "Petukhov": |
---|
| 520 | |
---|
| 521 | "Outer Side Friction Factor for Heat Transfer - turbulent Flow" |
---|
| 522 | Outer.HeatTransfer.fi = 1/(1.82*log(Outer.HeatTransfer.Re)-1.64)^2; |
---|
| 523 | |
---|
| 524 | "Nusselt Number" |
---|
| 525 | Outer.HeatTransfer.Nu*(1.07+(12.7*sqrt(0.125*Outer.HeatTransfer.fi)*((Outer.HeatTransfer.PR)^(2/3) -1))) = 0.125*Outer.HeatTransfer.fi*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR; |
---|
| 526 | |
---|
| 527 | case "SiederTate": |
---|
| 528 | |
---|
| 529 | "Nusselt Number" |
---|
| 530 | Outer.HeatTransfer.Nu = 0.027*(Outer.HeatTransfer.PR)^(1/3)*(Outer.HeatTransfer.Re)^(4/5); |
---|
| 531 | |
---|
| 532 | "Outer Side Friction Factor for Heat Transfer - turbulent Flow" |
---|
| 533 | Outer.HeatTransfer.fi = 1/(1.82*log(Outer.HeatTransfer.Re)-1.64)^2; |
---|
| 534 | |
---|
| 535 | end |
---|
| 536 | |
---|
| 537 | when Outer.HeatTransfer.Re < 10000 switchto "transition"; |
---|
| 538 | |
---|
| 539 | end |
---|
| 540 | |
---|
| 541 | "Inner Pipe Film Coefficient" |
---|
| 542 | Inner.HeatTransfer.hcoeff = (Inner.HeatTransfer.Nu*Inner.Properties.Average.K/DiInner)*Inner.HeatTransfer.Phi; |
---|
| 543 | |
---|
| 544 | "Outer Pipe Film Coefficient" |
---|
| 545 | Outer.HeatTransfer.hcoeff= (Outer.HeatTransfer.Nu*Outer.Properties.Average.K/Outer.HeatTransfer.Dh)*Outer.HeatTransfer.Phi; |
---|
| 546 | |
---|
| 547 | "Pressure Drop Outer Stream" |
---|
| 548 | OutletOuter.P = InletOuter.P - Outer.PressureDrop.Pdrop; |
---|
| 549 | |
---|
| 550 | "Pressure Drop Inner Stream" |
---|
| 551 | OutletInner.P = InletInner.P - Inner.PressureDrop.Pdrop; |
---|
| 552 | |
---|
| 553 | "Outer Pipe Pressure Drop for friction" |
---|
| 554 | Outer.PressureDrop.Pdrop = (2*Outer.PressureDrop.fi*Lpipe*Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean^2)/(Outer.PressureDrop.Dh*Outer.HeatTransfer.Phi); |
---|
| 555 | |
---|
| 556 | "Inner Pipe Pressure Drop for friction" |
---|
| 557 | Inner.PressureDrop.Pdrop = (2*Inner.PressureDrop.fi*Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(DiInner*Inner.HeatTransfer.Phi); |
---|
| 558 | |
---|
| 559 | "Outer Pipe Phi correction" |
---|
| 560 | Outer.HeatTransfer.Phi = (Outer.Properties.Average.Mu/Outer.Properties.Wall.Mu)^0.14; |
---|
| 561 | |
---|
| 562 | "Inner Pipe Phi correction" |
---|
| 563 | Inner.HeatTransfer.Phi = (Inner.Properties.Average.Mu/Inner.Properties.Wall.Mu)^0.14; |
---|
| 564 | |
---|
| 565 | "Outer Pipe Prandtl Number" |
---|
| 566 | Outer.HeatTransfer.PR = ((Outer.Properties.Average.Cp/Outer.Properties.Average.Mw)*Outer.Properties.Average.Mu)/Outer.Properties.Average.K; |
---|
| 567 | |
---|
| 568 | "Inner Pipe Prandtl Number" |
---|
| 569 | Inner.HeatTransfer.PR = ((Inner.Properties.Average.Cp/Inner.Properties.Average.Mw)*Inner.Properties.Average.Mu)/Inner.Properties.Average.K; |
---|
| 570 | |
---|
| 571 | "Outer Pipe Reynolds Number for Heat Transfer" |
---|
| 572 | Outer.HeatTransfer.Re = (Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean*Outer.HeatTransfer.Dh)/Outer.Properties.Average.Mu; |
---|
| 573 | |
---|
| 574 | "Outer Pipe Reynolds Number for Pressure Drop" |
---|
| 575 | Outer.PressureDrop.Re = (Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean*Outer.PressureDrop.Dh)/Outer.Properties.Average.Mu; |
---|
| 576 | |
---|
| 577 | "Inner Pipe Reynolds Number for Heat Transfer" |
---|
| 578 | Inner.HeatTransfer.Re = (Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean*Inner.HeatTransfer.Dh)/Inner.Properties.Average.Mu; |
---|
| 579 | |
---|
| 580 | "Inner Pipe Reynolds Number for Pressure Drop" |
---|
| 581 | Inner.PressureDrop.Re = Inner.HeatTransfer.Re; |
---|
| 582 | |
---|
| 583 | "Outer Pipe Velocity" |
---|
| 584 | Outer.HeatTransfer.Vmean*(Outer.HeatTransfer.As*Outer.Properties.Average.rho) = Outer.Properties.Inlet.Fw; |
---|
| 585 | |
---|
| 586 | "Inner Pipe Velocity" |
---|
| 587 | Inner.HeatTransfer.Vmean*(Inner.HeatTransfer.As*Inner.Properties.Average.rho) = Inner.Properties.Inlet.Fw; |
---|
| 588 | |
---|
| 589 | "Overall Heat Transfer Coefficient Clean" |
---|
| 590 | Details.Uc*((DoInner/(Inner.HeatTransfer.hcoeff*DiInner) )+(DoInner*ln(DoInner/DiInner)/(2*Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1; |
---|
| 591 | |
---|
| 592 | "Overall Heat Transfer Coefficient Dirty" |
---|
| 593 | Details.Ud*(Rfi*(DoInner/DiInner) + Rfo + (DoInner/(Inner.HeatTransfer.hcoeff*DiInner) )+(DoInner*ln(DoInner/DiInner)/(2*Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1; |
---|
| 594 | |
---|
| 595 | end |
---|
| 596 | |
---|
| 597 | Model DoublePipe_NTU as DoublePipe_Basic |
---|
| 598 | |
---|
| 599 | ATTRIBUTES |
---|
| 600 | |
---|
| 601 | Pallete = false; |
---|
| 602 | Brief = "Double Pipe Heat Exchanger - NTU Method"; |
---|
| 603 | Info = |
---|
| 604 | "to be documented."; |
---|
| 605 | |
---|
| 606 | PARAMETERS |
---|
| 607 | |
---|
| 608 | FlowDirection as Switcher (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent"); |
---|
| 609 | |
---|
| 610 | VARIABLES |
---|
| 611 | |
---|
| 612 | Method as NTU_Basic (Brief="NTU Method of Calculation"); |
---|
| 613 | |
---|
| 614 | EQUATIONS |
---|
| 615 | |
---|
| 616 | "Number of Units Transference" |
---|
| 617 | Method.NTU*Method.Cmin = Details.Ud*Pi*DoInner*Lpipe; |
---|
| 618 | |
---|
| 619 | "Minimum Heat Capacity" |
---|
| 620 | Method.Cmin = min([Method.Ch,Method.Cc]); |
---|
| 621 | |
---|
| 622 | "Maximum Heat Capacity" |
---|
| 623 | Method.Cmax = max([Method.Ch,Method.Cc]); |
---|
| 624 | |
---|
| 625 | "Thermal Capacity Ratio" |
---|
| 626 | Method.Cr = Method.Cmin/Method.Cmax; |
---|
| 627 | |
---|
| 628 | "Effectiveness Correction" |
---|
| 629 | Method.Eft1 = 1; |
---|
| 630 | |
---|
| 631 | if Method.Cr equal 0 |
---|
| 632 | |
---|
| 633 | then |
---|
| 634 | "Effectiveness" |
---|
| 635 | Method.Eft = 1-exp(-Method.NTU); |
---|
| 636 | |
---|
| 637 | else |
---|
| 638 | |
---|
| 639 | switch FlowDirection |
---|
| 640 | |
---|
| 641 | case "cocurrent": |
---|
| 642 | |
---|
| 643 | "Effectiveness in Cocurrent Flow" |
---|
| 644 | Method.Eft = (1-exp(-Method.NTU*(1+Method.Cr)))/(1+Method.Cr); |
---|
| 645 | |
---|
| 646 | case "counter": |
---|
| 647 | |
---|
| 648 | if Method.Cr equal 1 |
---|
| 649 | |
---|
| 650 | then |
---|
| 651 | |
---|
| 652 | "Effectiveness in Counter Flow" |
---|
| 653 | Method.Eft = Method.NTU/(1+Method.NTU); |
---|
| 654 | |
---|
| 655 | else |
---|
| 656 | |
---|
| 657 | "Effectiveness in Counter Flow" |
---|
| 658 | Method.Eft = (1-exp(-Method.NTU*(1-Method.Cr)))/(1-Method.Cr*exp(-Method.NTU*(1-Method.Cr))); |
---|
| 659 | |
---|
| 660 | end |
---|
| 661 | |
---|
| 662 | end |
---|
| 663 | |
---|
| 664 | end |
---|
| 665 | |
---|
| 666 | switch HotSide |
---|
| 667 | |
---|
| 668 | case "outer": |
---|
| 669 | |
---|
| 670 | "Duty" |
---|
| 671 | Details.Q = Method.Eft*Method.Cmin*(InletOuter.T-InletInner.T); |
---|
| 672 | |
---|
| 673 | "Hot Stream Heat Capacity" |
---|
| 674 | Method.Ch = InletOuter.F*Outer.Properties.Average.Cp; |
---|
| 675 | |
---|
| 676 | "Cold Stream Heat Capacity" |
---|
| 677 | Method.Cc = InletInner.F*Inner.Properties.Average.Cp; |
---|
| 678 | |
---|
| 679 | when InletInner.T > InletOuter.T switchto "inner"; |
---|
| 680 | |
---|
| 681 | case "inner": |
---|
| 682 | |
---|
| 683 | "Duty" |
---|
| 684 | Details.Q = Method.Eft*Method.Cmin*(InletInner.T-InletOuter.T); |
---|
| 685 | |
---|
| 686 | "Cold Stream Heat Capacity" |
---|
| 687 | Method.Cc = InletOuter.F*Outer.Properties.Average.Cp; |
---|
| 688 | |
---|
| 689 | "Hot Stream Heat Capacity" |
---|
| 690 | Method.Ch = InletInner.F*Inner.Properties.Average.Cp; |
---|
| 691 | |
---|
| 692 | when InletInner.T < InletOuter.T switchto "outer"; |
---|
| 693 | |
---|
| 694 | end |
---|
| 695 | |
---|
| 696 | end |
---|
| 697 | |
---|
| 698 | Model DoublePipe_LMTD as DoublePipe_Basic |
---|
| 699 | |
---|
| 700 | ATTRIBUTES |
---|
| 701 | Pallete = false; |
---|
| 702 | Brief = "Double Pipe Heat Exchanger - LMTD Method"; |
---|
| 703 | Info = |
---|
| 704 | "to be documente."; |
---|
| 705 | |
---|
| 706 | PARAMETERS |
---|
| 707 | |
---|
| 708 | FlowDirection as Switcher (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent"); |
---|
| 709 | |
---|
| 710 | VARIABLES |
---|
| 711 | |
---|
| 712 | Method as LMTD_Basic (Brief="LMTD Method of Calculation"); |
---|
| 713 | |
---|
| 714 | EQUATIONS |
---|
| 715 | |
---|
| 716 | "Exchange Surface Area" |
---|
| 717 | Details.Q = Details.Ud*Pi*DoInner*Lpipe*Method.LMTD; |
---|
| 718 | |
---|
| 719 | "LMTD Correction Factor - True counter ou cocurrent flow" |
---|
| 720 | Method.Fc = 1; |
---|
| 721 | |
---|
| 722 | switch HotSide |
---|
| 723 | |
---|
| 724 | case "outer": |
---|
| 725 | |
---|
| 726 | switch FlowDirection |
---|
| 727 | |
---|
| 728 | case "cocurrent": |
---|
| 729 | |
---|
| 730 | "Temperature Difference at Inlet - Cocurrent Flow" |
---|
| 731 | Method.DT0 = InletOuter.T - InletInner.T; |
---|
| 732 | |
---|
| 733 | "Temperature Difference at Outlet - Cocurrent Flow" |
---|
| 734 | Method.DTL = OutletOuter.T - OutletInner.T; |
---|
| 735 | |
---|
| 736 | case "counter": |
---|
| 737 | |
---|
| 738 | "Temperature Difference at Inlet - Counter Flow" |
---|
| 739 | Method.DT0 = InletOuter.T - OutletInner.T; |
---|
| 740 | |
---|
| 741 | "Temperature Difference at Outlet - Counter Flow" |
---|
| 742 | Method.DTL = OutletOuter.T - InletInner.T; |
---|
| 743 | |
---|
| 744 | |
---|
| 745 | end |
---|
| 746 | |
---|
| 747 | when InletInner.T > InletOuter.T switchto "inner"; |
---|
| 748 | |
---|
| 749 | case "inner": |
---|
| 750 | |
---|
| 751 | switch FlowDirection |
---|
| 752 | |
---|
| 753 | case "cocurrent": |
---|
| 754 | |
---|
| 755 | "Temperature Difference at Inlet - Cocurrent Flow" |
---|
| 756 | Method.DT0 = InletInner.T - InletOuter.T; |
---|
| 757 | |
---|
| 758 | "Temperature Difference at Outlet - Cocurrent Flow" |
---|
| 759 | Method.DTL = OutletInner.T - OutletOuter.T; |
---|
| 760 | |
---|
| 761 | case "counter": |
---|
| 762 | |
---|
| 763 | "Temperature Difference at Inlet - Counter Flow" |
---|
| 764 | Method.DT0 = InletInner.T - OutletOuter.T; |
---|
| 765 | |
---|
| 766 | "Temperature Difference at Outlet - Counter Flow" |
---|
| 767 | Method.DTL = OutletInner.T - InletOuter.T; |
---|
| 768 | |
---|
| 769 | end |
---|
| 770 | |
---|
| 771 | when InletInner.T < InletOuter.T switchto "outer"; |
---|
| 772 | |
---|
| 773 | end |
---|
| 774 | |
---|
| 775 | end |
---|