Changeset 472 for trunk/eml


Ignore:
Timestamp:
Mar 6, 2008, 8:43:11 PM (14 years ago)
Author:
gerson bicca
Message:

Double Pipe: added option to solve convergence problems from a simplified model

File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/eml/heat_exchangers/DoublePipe.mso

    r442 r472  
    4747        OuterTurbulentCorrelation   as Switcher         (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov");
    4848
     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       
    4952        Pi                              as constant             (Brief="Pi Number",Default=3.14159265, Symbol = "\pi");
    5053        DoInner         as length                       (Brief="Outside Diameter of Inner Pipe",Lower=1e-6);
     
    475478        Outer.HeatTransfer.hcoeff= (Outer.HeatTransfer.Nu*Outer.Properties.Average.K/Outer.HeatTransfer.Dh)*Outer.HeatTransfer.Phi;
    476479
     480switch CalculationApproach
     481       
     482        case "Full":
     483       
    477484"Total Pressure Drop Outer Stream"
    478         Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric+Outer.PressureDrop.Pd_ret;
     485        Outer.PressureDrop.Pdrop  = Outer.PressureDrop.Pd_fric;
    479486
    480487"Total Pressure Drop Inner Stream"
    481         Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric+Inner.PressureDrop.Pd_ret;
     488        Inner.PressureDrop.Pdrop  = Inner.PressureDrop.Pd_fric;
    482489       
    483490"Pressure Drop Outer Stream"
     
    492499"Inner Pipe Pressure Drop for friction"
    493500        Inner.PressureDrop.Pd_fric = (2*Inner.PressureDrop.fi*Lpipe*Inner.Properties.Average.rho*Inner.HeatTransfer.Vmean^2)/(DiInner*Inner.HeatTransfer.Phi);
     501
     502
     503        case "Simplified":
     504       
     505"Total Pressure Drop Outer Stream"
     506        Outer.PressureDrop.Pdrop  = 0*'kPa';
     507
     508"Total Pressure Drop Inner Stream"
     509        Inner.PressureDrop.Pdrop  = 0*'kPa';
     510       
     511"Pressure Drop Outer Stream"
     512        OutletOuter.P  = InletOuter.P;
     513
     514"Pressure Drop Inner Stream"
     515        OutletInner.P  = InletInner.P;
     516       
     517"Outer Pipe Pressure Drop for friction"
     518        Outer.PressureDrop.Pd_fric = 0*'kPa';
     519       
     520"Inner Pipe Pressure Drop for friction"
     521        Inner.PressureDrop.Pd_fric = 0*'kPa';
     522
     523end
    494524
    495525"Outer Pipe Pressure Drop due to return"
     
    639669        case "outer":
    640670
     671switch CalculationApproach
     672       
     673        case "Full":
     674       
    641675"Duty"
    642676        Details.Q       = Method.Eft*Method.Cmin*(InletOuter.T-InletInner.T);
    643677
     678        case "Simplified":
     679       
     680"Duty"
     681        Details.Q       = Qestimated;
     682
     683end
     684
    644685"Hot Stream Heat Capacity"
    645686        Method.Ch  = InletOuter.F*Outer.Properties.Average.Cp;
     
    652693        case "inner":
    653694
     695switch CalculationApproach
     696       
     697        case "Full":
     698       
    654699"Duty"
    655700        Details.Q       = Method.Eft*Method.Cmin*(InletInner.T-InletOuter.T);
     701
     702        case "Simplified":
     703
     704"Duty"
     705        Details.Q       = Qestimated;
     706
     707end
    656708
    657709"Cold Stream Heat Capacity"
     
    715767EQUATIONS
    716768
    717 "Exchange Surface Area"
     769switch CalculationApproach
     770       
     771        case "Full":
     772       
     773"Duty"
    718774        Details.Q = Details.Ud*Pi*DoInner*Lpipe*Method.LMTD;
    719775       
     776        case "Simplified":
     777       
     778"Duty"
     779        Details.Q = Qestimated;
     780
     781end
     782
    720783"LMTD Correction Factor - True counter ou cocurrent flow"
    721784        Method.Fc = 1;
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