Ignore:
Timestamp:
May 24, 2008, 6:35:24 PM (15 years ago)
Author:
gerson bicca
Message:

updated double pipe model

File:
1 edited

Legend:

Unmodified
Added
Removed

  • trunk/eml/heat_exchangers/DoublePipe.mso

    r478 r525  
    1919using "HEX_Engine";
    2020
     21Model DoublePipe_Geometry
     22
     23ATTRIBUTES
     24        Pallete         = false;
     25        Brief           = "double pipe geometrical parameters.";
     26        Info            =
     27        "to be documented.";
     28
     29PARAMETERS
     30
     31outer PP            as Plugin           (Brief="External Physical Properties", Type="PP");
     32outer NComp     as Integer      (Brief="Number of Components",Hidden=true);
     33       
     34        M(NComp)        as molweight    (Brief="Component Mol Weight",Hidden=true);
     35       
     36        Pi                      as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi",Hidden=true);
     37        DoInner         as length                       (Brief="Outside Diameter of Inner Pipe",Lower=1e-6);
     38        DiInner         as length                       (Brief="Inside Diameter of Inner Pipe",Lower=1e-10);
     39        DiOuter         as length                       (Brief="Inside Diameter of Outer pipe",Lower=1e-10);
     40        Lpipe           as length                       (Brief="Effective Tube Length of one segment of Pipe",Lower=0.1, Symbol = "L_{pipe}");
     41        Kwall           as conductivity         (Brief="Tube Wall Material Thermal Conductivity",Default=1.0, Symbol = "K_{wall}");
     42        Rfi                     as positive                     (Brief="Inside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
     43        Rfo                     as positive                     (Brief="Outside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
     44
     45SET
     46
     47#"Component Molecular Weight"
     48        M  = PP.MolecularWeight();
     49       
     50#"Pi Number"
     51        Pi = 3.14159265;
     52
     53end
    2154
    2255Model DoublePipe_Basic
    … …  
    3164
    3265outer PP            as Plugin           (Brief="External Physical Properties", Type="PP");
    33 outer NComp     as Integer      (Brief="Number of Components");
    34        
    35         M(NComp)        as molweight    (Brief="Component Mol Weight");
    36        
    37         HotSide                         as Switcher             (Brief="Flag for Fluid Alocation ",Valid=["outer","inner"],Default="outer");
    38         innerFlowRegime         as Switcher     (Brief="Inner Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar");
    39         outerFlowRegime         as Switcher     (Brief="Outer Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar");
     66outer NComp     as Integer      (Brief="Number of Components",Hidden=true);
     67       
     68        M(NComp)        as molweight    (Brief="Component Mol Weight",Hidden=true);
     69       
     70        HotSide                         as Switcher     (Brief="Flag for Fluid Alocation ",Valid=["outer","inner"],Default="outer",Hidden=true);
     71        innerFlowRegime         as Switcher     (Brief="Inner Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar",Hidden=true);
     72        outerFlowRegime         as Switcher     (Brief="Outer Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar",Hidden=true);
    4073
    4174        InnerLaminarCorrelation         as Switcher     (Brief="Heat Transfer Correlation in Laminar Flow for the Inner Side",Valid=["Hausen","Schlunder"],Default="Hausen");
    42         InnerTransitionCorrelation  as Switcher         (Brief="Heat Transfer Correlation in Transition Flow for the Inner Side",Valid=["Gnielinski","Hausen"],Default="Gnielinski");
     75        InnerTransitionCorrelation  as Switcher (Brief="Heat Transfer Correlation in Transition Flow for the Inner Side",Valid=["Gnielinski","Hausen"],Default="Gnielinski");
    4376        InnerTurbulentCorrelation   as Switcher (Brief="Heat Transfer Correlation in Turbulent Flow for the Inner Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
    4477
    … …  
    4780        OuterTurbulentCorrelation   as Switcher         (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
    4881
    49         CalculationApproach                             as Switcher             (Brief="Options for convergence Calculations ",Valid=["Simplified","Full"],Default="Full");
    50         Qestimated                                                              as power                                (Brief="Estimated Duty", Default=70, Lower=1e-6, Upper=1e10);
    51        
    52         Pi                              as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi");
    53         DoInner         as length                       (Brief="Outside Diameter of Inner Pipe",Lower=1e-6);
    54         DiInner as length                       (Brief="Inside Diameter of Inner Pipe",Lower=1e-10);
    55         DiOuter as length                       (Brief="Inside Diameter of Outer pipe",Lower=1e-10);
    56         Lpipe           as length                       (Brief="Effective Tube Length of one segment of Pipe",Lower=0.1, Symbol = "L_{pipe}");
    57         Kwall           as conductivity         (Brief="Tube Wall Material Thermal Conductivity",Default=1.0, Symbol = "K_{wall}");
    58         Rfi                     as positive                     (Brief="Inside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
    59         Rfo                     as positive                     (Brief="Outside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
     82        CalculationApproach                     as Switcher             (Brief="Options for convergence Calculations ",Valid=["Simplified","Full"],Default="Full");
     83        Qestimated                                      as power                (Brief="Estimated Duty", Default=70, Lower=1e-6, Upper=1e10);
    6084
    6185VARIABLES
    6286
    63 in  InletInner          as stream               (Brief="Inlet Inner Stream", PosX=0, PosY=0.5225, Symbol="_{inInner}");
    64 in  InletOuter          as stream               (Brief="Inlet Outer Stream", PosX=0.2805, PosY=0, Symbol="_{inOuter}");
    65 out OutletInner         as streamPH     (Brief="Outlet Inner Stream", PosX=1, PosY=0.5225, Symbol="_{outInner}");
    66 out OutletOuter         as streamPH     (Brief="Outlet Outer Stream", PosX=0.7264, PosY=1, Symbol="_{outOuter}");
     87        Geometry                as DoublePipe_Geometry  (Brief="Double pipe geometry",Symbol=" ");     
     88in  InletInner          as stream                               (Brief="Inlet Inner Stream", PosX=0, PosY=0.5225, Symbol="_{inInner}");
     89in  InletOuter          as stream                               (Brief="Inlet Outer Stream", PosX=0.2805, PosY=0, Symbol="_{inOuter}");
     90out OutletInner         as streamPH                     (Brief="Outlet Inner Stream", PosX=1, PosY=0.5225, Symbol="_{outInner}");
     91out OutletOuter         as streamPH                     (Brief="Outlet Outer Stream", PosX=0.7264, PosY=1, Symbol="_{outOuter}");
    6792
    6893        Details         as Details_Main         (Brief="Some Details in the Heat Exchanger", Symbol=" ");
    … …  
    7297SET
    7398
    74 #"Component Molecular Weight"
    75         M  = PP.MolecularWeight();
    76        
    77 #"Pi Number"
    78         Pi      = 3.14159265;
    79        
    8099#"Inner Pipe Cross Sectional Area for Flow"
    81         Inner.HeatTransfer.As=Pi*DiInner*DiInner/4;
     100        Inner.HeatTransfer.As=Geometry.Pi*Geometry.DiInner*Geometry.DiInner/4;
    82101       
    83102#"Outer Pipe Cross Sectional Area for Flow"
    84         Outer.HeatTransfer.As=Pi*(DiOuter*DiOuter - DoInner*DoInner)/4;
     103        Outer.HeatTransfer.As=Geometry.Pi*(Geometry.DiOuter*Geometry.DiOuter - Geometry.DoInner*Geometry.DoInner)/4;
    85104       
    86105#"Inner Pipe Hydraulic Diameter for Heat Transfer"
    87         Inner.HeatTransfer.Dh=DiInner;
     106        Inner.HeatTransfer.Dh=Geometry.DiInner;
    88107       
    89108#"Outer Pipe Hydraulic Diameter for Heat Transfer"
    90         Outer.HeatTransfer.Dh=(DiOuter*DiOuter-DoInner*DoInner)/DoInner;
     109        Outer.HeatTransfer.Dh=(Geometry.DiOuter*Geometry.DiOuter-Geometry.DoInner*Geometry.DoInner)/Geometry.DoInner;
    91110
    92111#"Inner Pipe Hydraulic Diameter for Pressure Drop"
    93         Inner.PressureDrop.Dh=DiInner;
     112        Inner.PressureDrop.Dh=Geometry.DiInner;
    94113       
    95114#"Outer Pipe Hydraulic Diameter for Pressure Drop"
    96         Outer.PressureDrop.Dh=DiOuter-DoInner;
     115        Outer.PressureDrop.Dh=Geometry.DiOuter-Geometry.DoInner;
    97116
    98117EQUATIONS
    … …  
    272291
    273292"Exchange Surface Area for one segment of pipe"
    274         Details.A=Pi*DoInner*Lpipe;
     293        Details.A=Geometry.Pi*Geometry.DoInner*Geometry.Lpipe;
    275294
    276295switch innerFlowRegime
    … …  
    338357
    339358"Nusselt Number"
    340         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));
     359        Inner.HeatTransfer.Nu = 3.665 + ((0.19*((Geometry.DiInner/Geometry.Lpipe)*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR)^0.8)/(1+0.117*((Geometry.DiInner/Geometry.Lpipe)*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR)^0.467));
    341360       
    342361        case "Schlunder":
    343362
    344363"Nusselt Number"
    345         Inner.HeatTransfer.Nu = (49.027896+4.173281*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR*(DiInner/Lpipe))^(1/3);
     364        Inner.HeatTransfer.Nu = (49.027896+4.173281*Inner.HeatTransfer.Re*Inner.HeatTransfer.PR*(Geometry.DiInner/Geometry.Lpipe))^(1/3);
    346365
    347366end
    … …  
    364383
    365384"Nusselt Number"
    366         Inner.HeatTransfer.Nu =0.116*(Inner.HeatTransfer.Re^(0.667)-125)*Inner.HeatTransfer.PR^(0.333)*(1+(DiInner/Lpipe)^0.667);
     385        Inner.HeatTransfer.Nu =0.116*(Inner.HeatTransfer.Re^(0.667)-125)*Inner.HeatTransfer.PR^(0.333)*(1+(Geometry.DiInner/Geometry.Lpipe)^0.667);
    367386       
    368387end
    … …  
    409428
    410429"Nusselt Number"
    411         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));
     430        Outer.HeatTransfer.Nu = 3.665 + ((0.19*((Outer.HeatTransfer.Dh/Geometry.Lpipe)*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR)^0.8)/(1+0.117*((Outer.HeatTransfer.Dh/Geometry.Lpipe)*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR)^0.467));
    412431       
    413432        case "Schlunder":
    414433
    415434"Nusselt Number"
    416         Outer.HeatTransfer.Nu = (49.027896+4.173281*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR*(Outer.HeatTransfer.Dh/Lpipe))^(1/3);
     435        Outer.HeatTransfer.Nu = (49.027896+4.173281*Outer.HeatTransfer.Re*Outer.HeatTransfer.PR*(Outer.HeatTransfer.Dh/Geometry.Lpipe))^(1/3);
    417436
    418437end
    … …  
    435454
    436455"Nusselt Number"
    437         Outer.HeatTransfer.Nu = 0.116*(Outer.HeatTransfer.Re^(0.667)-125)*Outer.HeatTransfer.PR^(0.333)*(1+(Outer.HeatTransfer.Dh/Lpipe)^0.667);
     456        Outer.HeatTransfer.Nu = 0.116*(Outer.HeatTransfer.Re^(0.667)-125)*Outer.HeatTransfer.PR^(0.333)*(1+(Outer.HeatTransfer.Dh/Geometry.Lpipe)^0.667);
    438457
    439458
    … …  
    473492
    474493"Inner Pipe Film Coefficient"
    475         Inner.HeatTransfer.hcoeff = (Inner.HeatTransfer.Nu*Inner.Properties.Average.K/DiInner)*Inner.HeatTransfer.Phi;
     494        Inner.HeatTransfer.hcoeff = (Inner.HeatTransfer.Nu*Inner.Properties.Average.K/Geometry.DiInner)*Inner.HeatTransfer.Phi;
    476495
    477496"Outer Pipe Film Coefficient"
    … …  
    495514       
    496515"Outer Pipe Pressure Drop for friction"
    497         Outer.PressureDrop.Pd_fric = (2*Outer.PressureDrop.fi*Lpipe*Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean^2)/(Outer.PressureDrop.Dh*Outer.HeatTransfer.Phi);
     516        Outer.PressureDrop.Pd_fric = (2*Outer.PressureDrop.fi*Geometry.Lpipe*Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean^2)/(Outer.PressureDrop.Dh*Outer.HeatTransfer.Phi);
    498517       
    499518"Inner Pipe Pressure Drop for friction"
    500         Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(DiInner*Inner.HeatTransfer.Phi);
     519        Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Geometry.Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(Geometry.DiInner*Inner.HeatTransfer.Phi);
    501520
    502521
    … …  
    504523       
    505524"Total Pressure Drop Outer Stream"
    506         Outer.PressureDrop.Pdrop  = 0*'kPa';
     525        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
    507526
    508527"Total Pressure Drop Inner Stream"
    509         Inner.PressureDrop.Pdrop  = 0*'kPa';
     528        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
    510529       
    511530"Pressure Drop Outer Stream"
    512         OutletOuter.P  = InletOuter.P;
     531        OutletOuter.P  = InletOuter.P - Outer.PressureDrop.Pdrop;
    513532
    514533"Pressure Drop Inner Stream"
    515         OutletInner.P  = InletInner.P;
     534        OutletInner.P  = InletInner.P - Inner.PressureDrop.Pdrop;
    516535       
    517536"Outer Pipe Pressure Drop for friction"
    518         Outer.PressureDrop.Pd_fric = 0*'kPa';
     537        Outer.PressureDrop.Pd_fric = 0.01*InletOuter.P;
    519538       
    520539"Inner Pipe Pressure Drop for friction"
    521         Inner.PressureDrop.Pd_fric = 0*'kPa';
     540        Inner.PressureDrop.Pd_fric = 0.01*InletInner.P;
    522541
    523542end
    … …  
    560579
    561580"Overall Heat Transfer Coefficient Clean"
    562         Details.Uc*((DoInner/(Inner.HeatTransfer.hcoeff*DiInner) )+(DoInner*ln(DoInner/DiInner)/(2*Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1;
     581        Details.Uc*((Geometry.DoInner/(Inner.HeatTransfer.hcoeff*Geometry.DiInner) )+(Geometry.DoInner*ln(Geometry.DoInner/Geometry.DiInner)/(2*Geometry.Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1;
    563582
    564583"Overall Heat Transfer Coefficient Dirty"
    565         Details.Ud*(Rfi*(DoInner/DiInner) +  Rfo + (DoInner/(Inner.HeatTransfer.hcoeff*DiInner) )+(DoInner*ln(DoInner/DiInner)/(2*Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1;
     584        Details.Ud*(Geometry.Rfi*(Geometry.DoInner/Geometry.DiInner) +  Geometry.Rfo + (Geometry.DoInner/(Inner.HeatTransfer.hcoeff*Geometry.DiInner) )+(Geometry.DoInner*ln(Geometry.DoInner/Geometry.DiInner)/(2*Geometry.Kwall))+(1/(Outer.HeatTransfer.hcoeff)))=1;
    566585
    567586end
    … …  
    624643       
    625644"Number of Units Transference"
    626         Method.NTU*Method.Cmin = Details.Ud*Pi*DoInner*Lpipe;
     645        Method.NTU*Method.Cmin = Details.Ud*Geometry.Pi*Geometry.DoInner*Geometry.Lpipe;
    627646       
    628647"Minimum Heat Capacity"
    … …  
    796815       
    797816"Duty"
    798         Details.Q = Details.Ud*Pi*DoInner*Lpipe*Method.LMTD;
     817        Details.Q = Details.Ud*Geometry.Pi*Geometry.DoInner*Geometry.Lpipe*Method.LMTD;
    799818       
    800819        case "Simplified":
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