Ignore:
Timestamp:
Jul 8, 2008, 5:51:28 PM (14 years ago)
Author:
gerson bicca
Message:

updated

File:
1 edited

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  • trunk/eml/heat_exchangers/DoublePipe.mso

    r525 r551  
    2424        Pallete         = false;
    2525        Brief           = "double pipe geometrical parameters.";
    26         Info            =
    27         "to be documented.";
    2826
    2927PARAMETERS
    3028
    31 outer PP            as Plugin           (Brief="External Physical Properties", Type="PP");
     29outer PP                as Plugin               (Brief="External Physical Properties", Type="PP");
    3230outer NComp     as Integer      (Brief="Number of Components",Hidden=true);
    33        
     31
    3432        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);
     33
     34        Pi                                      as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi",Hidden=true);
     35        DoInner                 as length                       (Brief="Outside Diameter of Inner Pipe",Lower=1e-6);
    3836        DiInner         as length                       (Brief="Inside Diameter of Inner Pipe",Lower=1e-10);
    3937        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);
     38        Lpipe                   as length                       (Brief="Effective Tube Length of one segment of Pipe",Lower=0.1, Symbol = "L_{pipe}");
     39        Kwall                   as conductivity         (Brief="Tube Wall Material Thermal Conductivity",Default=1.0, Symbol = "K_{wall}");
     40        Rfi                             as positive                     (Brief="Inside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
     41        Rfo                             as positive                     (Brief="Outside Fouling Resistance",Unit='m^2*K/kW',Default=1e-6,Lower=0);
    4442
    4543SET
     
    4745#"Component Molecular Weight"
    4846        M  = PP.MolecularWeight();
    49        
     47
    5048#"Pi Number"
    5149        Pi = 3.14159265;
     
    5957        Brief           = "Basic Equations for rigorous double pipe heat exchanger model.";
    6058        Info            =
    61         "to be documented.";
     59        "Thermal analysis of double pipe heat exchanger using the NTU or LMTD Method.
     60
     61== References ==
     62
     63[1] E.A.D. Saunders, Heat Exchangers: Selection, Design and
     64 Construction, Longman, Harlow, 1988.
     65
     66[2] Serth, Robert W., Process Heat Transfer: Principles and Applications, Elsevier, 2007.
     67
     68[3] Gnielinski, V., Forced convection in ducts, in Heat Exchanger Design Handbook, Vol. 2
     69 Hemisphere Publishing Corp., New York, 1988.";
    6270
    6371PARAMETERS
    6472
    65 outer PP            as Plugin           (Brief="External Physical Properties", Type="PP");
     73outer PP                as Plugin               (Brief="External Physical Properties", Type="PP");
    6674outer NComp     as Integer      (Brief="Number of Components",Hidden=true);
    6775       
    6876        M(NComp)        as molweight    (Brief="Component Mol Weight",Hidden=true);
    6977       
    70         HotSide                         as Switcher     (Brief="Flag for Fluid Alocation ",Valid=["outer","inner"],Default="outer",Hidden=true);
     78        HotSide                                         as Switcher     (Brief="Flag for Fluid Alocation ",Valid=["outer","inner"],Default="outer",Hidden=true);
    7179        innerFlowRegime         as Switcher     (Brief="Inner Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar",Hidden=true);
    7280        outerFlowRegime         as Switcher     (Brief="Outer Flow Regime ",Valid=["laminar","transition","turbulent"],Default="laminar",Hidden=true);
    7381
    7482        InnerLaminarCorrelation         as Switcher     (Brief="Heat Transfer Correlation in Laminar Flow for the Inner Side",Valid=["Hausen","Schlunder"],Default="Hausen");
    75         InnerTransitionCorrelation  as Switcher (Brief="Heat Transfer Correlation in Transition Flow for the Inner Side",Valid=["Gnielinski","Hausen"],Default="Gnielinski");
     83        InnerTransitionCorrelation  as Switcher         (Brief="Heat Transfer Correlation in Transition Flow for the Inner Side",Valid=["Gnielinski","Hausen"],Default="Gnielinski");
    7684        InnerTurbulentCorrelation   as Switcher (Brief="Heat Transfer Correlation in Turbulent Flow for the Inner Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
    7785
     
    8088        OuterTurbulentCorrelation   as Switcher         (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
    8189
    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);
     90        CalculationApproach                     as Switcher     (Brief="Options for convergence Calculations ",Valid=["Simplified","Full"],Default="Full");
     91        Qestimated                                                      as power                (Brief="Estimated Duty", Default=70, Lower=1e-6, Upper=1e10);
    8492
    8593VARIABLES
    8694
    87         Geometry                as DoublePipe_Geometry  (Brief="Double pipe geometry",Symbol=" ");     
    88 in  InletInner          as stream                               (Brief="Inlet Inner Stream", PosX=0, PosY=0.5225, Symbol="_{inInner}");
    89 in  InletOuter          as stream                               (Brief="Inlet Outer Stream", PosX=0.2805, PosY=0, Symbol="_{inOuter}");
    90 out OutletInner         as streamPH                     (Brief="Outlet Inner Stream", PosX=1, PosY=0.5225, Symbol="_{outInner}");
    91 out OutletOuter         as streamPH                     (Brief="Outlet Outer Stream", PosX=0.7264, PosY=1, Symbol="_{outOuter}");
    92 
    93         Details         as Details_Main         (Brief="Some Details in the Heat Exchanger", Symbol=" ");
    94         Inner                   as Main_DoublePipe      (Brief="Inner Side of the Heat Exchanger", Symbol="_{Inner}");
    95         Outer                   as Main_DoublePipe      (Brief="Outer Side of the Heat Exchanger", Symbol="_{Outer}");
     95        Geometry                        as DoublePipe_Geometry  (Brief="Double pipe geometry",Symbol=" ");     
     96in  InletInner                  as stream                                                               (Brief="Inlet Inner Stream", PosX=0, PosY=0.5225, Symbol="_{inInner}");
     97in  InletOuter                  as stream                                                               (Brief="Inlet Outer Stream", PosX=0.2805, PosY=0, Symbol="_{inOuter}");
     98out OutletInner         as streamPH                                             (Brief="Outlet Inner Stream", PosX=1, PosY=0.5225, Symbol="_{outInner}");
     99out OutletOuter         as streamPH                                             (Brief="Outlet Outer Stream", PosX=0.7264, PosY=1, Symbol="_{outOuter}");
     100
     101        Details         as Details_Main                         (Brief="Some Details in the Heat Exchanger", Symbol=" ");
     102        Inner                   as Main_DoublePipe              (Brief="Inner Side of the Heat Exchanger", Symbol="_{Inner}");
     103        Outer                   as Main_DoublePipe              (Brief="Outer Side of the Heat Exchanger", Symbol="_{Outer}");
    96104
    97105SET
    98106
    99107#"Inner Pipe Cross Sectional Area for Flow"
    100         Inner.HeatTransfer.As=Geometry.Pi*Geometry.DiInner*Geometry.DiInner/4;
     108        Inner.HeatTransfer.As = 0.25*Geometry.Pi*Geometry.DiInner*Geometry.DiInner;
    101109       
    102110#"Outer Pipe Cross Sectional Area for Flow"
    103         Outer.HeatTransfer.As=Geometry.Pi*(Geometry.DiOuter*Geometry.DiOuter - Geometry.DoInner*Geometry.DoInner)/4;
     111        Outer.HeatTransfer.As  = 0.25*Geometry.Pi*(Geometry.DiOuter*Geometry.DiOuter - Geometry.DoInner*Geometry.DoInner);
    104112       
    105113#"Inner Pipe Hydraulic Diameter for Heat Transfer"
    106         Inner.HeatTransfer.Dh=Geometry.DiInner;
     114        Inner.HeatTransfer.Dh = Geometry.DiInner;
    107115       
    108116#"Outer Pipe Hydraulic Diameter for Heat Transfer"
    109         Outer.HeatTransfer.Dh=(Geometry.DiOuter*Geometry.DiOuter-Geometry.DoInner*Geometry.DoInner)/Geometry.DoInner;
     117        Outer.HeatTransfer.Dh = (Geometry.DiOuter*Geometry.DiOuter-Geometry.DoInner*Geometry.DoInner)/Geometry.DoInner;
    110118
    111119#"Inner Pipe Hydraulic Diameter for Pressure Drop"
    112         Inner.PressureDrop.Dh=Geometry.DiInner;
     120        Inner.PressureDrop.Dh = Geometry.DiInner;
    113121       
    114122#"Outer Pipe Hydraulic Diameter for Pressure Drop"
     
    141149        Inner.Properties.Average.Mw = sum(M*InletInner.z);
    142150
     151"Flow Mass Inlet Inner Stream"
     152        Inner.Properties.Inlet.Fw       =  sum(M*InletInner.z)*InletInner.F;
     153
     154"Flow Mass Outlet Inner Stream"
     155        Inner.Properties.Outlet.Fw      =  sum(M*OutletInner.z)*OutletInner.F;
     156
     157"Flow Mass Inlet Outer Stream"
     158        Outer.Properties.Inlet.Fw               =  sum(M*InletOuter.z)*InletOuter.F;
     159
     160"Flow Mass Outlet Outer Stream"
     161        Outer.Properties.Outlet.Fw      =  sum(M*OutletOuter.z)*OutletOuter.F;
     162
     163"Molar Balance Outer Stream"
     164        OutletOuter.F = InletOuter.F;
     165       
     166"Molar Balance Inner Stream"
     167        OutletInner.F = InletInner.F;
     168
     169"Outer Stream Molar Fraction Constraint"
     170        OutletOuter.z=InletOuter.z;
     171       
     172"Inner Stream Molar Fraction Constraint"
     173        OutletInner.z=InletInner.z;
     174
     175"Exchange Surface Area for one segment of pipe"
     176        Details.A=Geometry.Pi*Geometry.DoInner*Geometry.Lpipe;
     177
    143178if InletInner.v equal 0
    144179       
     
    266301end
    267302
    268 "Flow Mass Inlet Inner Stream"
    269         Inner.Properties.Inlet.Fw       =  sum(M*InletInner.z)*InletInner.F;
    270 
    271 "Flow Mass Outlet Inner Stream"
    272         Inner.Properties.Outlet.Fw      =  sum(M*OutletInner.z)*OutletInner.F;
    273 
    274 "Flow Mass Inlet Outer Stream"
    275         Outer.Properties.Inlet.Fw               =  sum(M*InletOuter.z)*InletOuter.F;
    276 
    277 "Flow Mass Outlet Outer Stream"
    278         Outer.Properties.Outlet.Fw      =  sum(M*OutletOuter.z)*OutletOuter.F;
    279 
    280 "Molar Balance Outer Stream"
    281         OutletOuter.F = InletOuter.F;
    282        
    283 "Molar Balance Inner Stream"
    284         OutletInner.F = InletInner.F;
    285 
    286 "Outer Stream Molar Fraction Constraint"
    287         OutletOuter.z=InletOuter.z;
    288        
    289 "InnerStream Molar Fraction Constraint"
    290         OutletInner.z=InletInner.z;
    291 
    292 "Exchange Surface Area for one segment of pipe"
    293         Details.A=Geometry.Pi*Geometry.DoInner*Geometry.Lpipe;
    294 
    295303switch innerFlowRegime
    296304       
     
    304312        case "transition":
    305313       
    306 "using Turbulent Flow - to be implemented"
     314"using Turbulent Flow"
    307315        (Inner.PressureDrop.fi-0.0035)*(Inner.PressureDrop.Re^0.42) = 0.264;
    308316
     
    312320        case "turbulent":
    313321
    314 "Inner Side Friction Factor - Turbulent Flow"
     322"Inner Side Friction Factor"
    315323        (Inner.PressureDrop.fi-0.0035)*(Inner.PressureDrop.Re^0.42) = 0.264;
    316324
     
    330338        case "transition":
    331339       
    332 "using Turbulent Flow - Transition Flow must be implemented"
     340"using Turbulent Flow"
    333341        (Outer.PressureDrop.fi-0.0035)*(Outer.PressureDrop.Re^0.42) = 0.264;
    334342
     
    338346        case "turbulent":
    339347
    340 "Outer Side Friction Factor - Turbulent Flow"
     348"Outer Side Friction Factor"
    341349        (Outer.PressureDrop.fi-0.0035)*(Outer.PressureDrop.Re^0.42) = 0.264;
    342350
     
    491499end
    492500
     501switch CalculationApproach
     502       
     503        case "Full":
     504       
     505"Total Pressure Drop Outer Stream"
     506        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
     507
     508"Total Pressure Drop Inner Stream"
     509        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
     510       
     511"Pressure Drop Outer Stream"
     512        OutletOuter.P  = InletOuter.P - Outer.PressureDrop.Pdrop;
     513
     514"Pressure Drop Inner Stream"
     515        OutletInner.P  = InletInner.P - Inner.PressureDrop.Pdrop;
     516       
     517"Outer Pipe Pressure Drop for friction"
     518        Outer.PressureDrop.Pd_fric = (2*Outer.PressureDrop.fi*Geometry.Lpipe*Outer.Properties.Average.rho*Outer.HeatTransfer.Vmean^2)/(Outer.PressureDrop.Dh*Outer.HeatTransfer.Phi);
     519       
     520"Inner Pipe Pressure Drop for friction"
     521        Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Geometry.Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(Geometry.DiInner*Inner.HeatTransfer.Phi);
     522
     523        case "Simplified":
     524       
     525"Total Pressure Drop Outer Stream"
     526        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
     527
     528"Total Pressure Drop Inner Stream"
     529        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
     530       
     531"Pressure Drop Outer Stream"
     532        OutletOuter.P  = InletOuter.P - Outer.PressureDrop.Pdrop;
     533
     534"Pressure Drop Inner Stream"
     535        OutletInner.P  = InletInner.P - Inner.PressureDrop.Pdrop;
     536       
     537"Outer Pipe Pressure Drop for friction"
     538        Outer.PressureDrop.Pd_fric = 0.01*InletOuter.P;
     539       
     540"Inner Pipe Pressure Drop for friction"
     541        Inner.PressureDrop.Pd_fric = 0.01*InletInner.P;
     542
     543end
     544
    493545"Inner Pipe Film Coefficient"
    494546        Inner.HeatTransfer.hcoeff = (Inner.HeatTransfer.Nu*Inner.Properties.Average.K/Geometry.DiInner)*Inner.HeatTransfer.Phi;
     
    497549        Outer.HeatTransfer.hcoeff= (Outer.HeatTransfer.Nu*Outer.Properties.Average.K/Outer.HeatTransfer.Dh)*Outer.HeatTransfer.Phi;
    498550
    499 switch CalculationApproach
    500        
    501         case "Full":
    502        
    503 "Total Pressure Drop Outer Stream"
    504         Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
    505 
    506 "Total Pressure Drop Inner Stream"
    507         Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
    508        
    509 "Pressure Drop Outer Stream"
    510         OutletOuter.P  = InletOuter.P - Outer.PressureDrop.Pdrop;
    511 
    512 "Pressure Drop Inner Stream"
    513         OutletInner.P  = InletInner.P - Inner.PressureDrop.Pdrop;
    514        
    515 "Outer Pipe Pressure Drop for friction"
    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);
    517        
    518 "Inner Pipe Pressure Drop for friction"
    519         Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Geometry.Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(Geometry.DiInner*Inner.HeatTransfer.Phi);
    520 
    521 
    522         case "Simplified":
    523        
    524 "Total Pressure Drop Outer Stream"
    525         Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
    526 
    527 "Total Pressure Drop Inner Stream"
    528         Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
    529        
    530 "Pressure Drop Outer Stream"
    531         OutletOuter.P  = InletOuter.P - Outer.PressureDrop.Pdrop;
    532 
    533 "Pressure Drop Inner Stream"
    534         OutletInner.P  = InletInner.P - Inner.PressureDrop.Pdrop;
    535        
    536 "Outer Pipe Pressure Drop for friction"
    537         Outer.PressureDrop.Pd_fric = 0.01*InletOuter.P;
    538        
    539 "Inner Pipe Pressure Drop for friction"
    540         Inner.PressureDrop.Pd_fric = 0.01*InletInner.P;
    541 
    542 end
    543 
    544551"Outer Pipe Pressure Drop due to return"
    545552        Outer.PressureDrop.Pd_ret = 0*'kPa';
     
    550557"Outer Pipe Phi correction"
    551558        Outer.HeatTransfer.Phi = (Outer.Properties.Average.Mu/Outer.Properties.Wall.Mu)^0.14;
    552        
     559
    553560"Inner Pipe Phi correction"
    554561        Inner.HeatTransfer.Phi  = (Inner.Properties.Average.Mu/Inner.Properties.Wall.Mu)^0.14;
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