Ignore:
Timestamp:
Jan 30, 2007, 7:42:28 PM (16 years ago)
Author:
gerson bicca
Message:

testing with switcher in heat exchangers model

File:
1 edited

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  • branches/newlanguage/eml/heat_exchangers/HeatExchangerSimplified.mso

    r145 r146  
    477477        Info            =
    478478        "write some information";
    479        
    480 EQUATIONS
     479
     480PARAMETERS
     481
     482LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann");
     483
     484VARIABLES
     485
     486R               as positive;
     487P               as positive;
     488Rho     as positive;
     489Phi    as positive;
     490
     491EQUATIONS
     492
     493"Capacity Ratio for LMTD Correction Fator"
     494        R*(Outlet.Cold.T - Inlet.Cold.T ) = (Inlet.Hot.T-Outlet.Hot.T);
     495
     496"Non - Dimensional Variable for LMTD Correction Fator"
     497        P*(Inlet.Hot.T- Inlet.Cold.T)= (Outlet.Cold.T-Inlet.Cold.T);
     498
    481499"Temperature Difference at Inlet"
    482500        DT0 = Inlet.Hot.T - Outlet.Cold.T;
     
    484502"Temperature Difference at Outlet"
    485503        DTL = Outlet.Hot.T - Inlet.Cold.T;
    486        
    487 "LMTD Correction Factor"
    488         Fc = HE.EshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
     504
     505"Rho: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
     506        Rho*(1-P*R) = (1-P);
     507
     508"Phi: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
     509        Phi  = (sqrt(((Inlet.Hot.T- Outlet.Hot.T)*(Inlet.Hot.T- Outlet.Hot.T))+((Outlet.Cold.T - Inlet.Cold.T)*(Outlet.Cold.T - Inlet.Cold.T))))/(2*((Inlet.Hot.T+ Outlet.Hot.T)-(Inlet.Cold.T+ Outlet.Cold.T)));
     510
     511switch LMTDcorrection
     512       
     513        case "Bowmann":
     514
     515 if R equal 1
     516       
     517    then
     518        Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214))));
     519
     520        else
     521        Fc = sqrt(R*R+1)*ln(abs((1-P*R)/(1-P)))/((1-R)*ln( abs( ( 2-P*(R+1-sqrt(R*R+1)))/ ( 2-P*(R + 1 + sqrt(R*R+1))))));
     522
     523end
     524
     525case "Fakeri":
     526
     527if Rho equal 1
     528       
     529        then
     530        Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi))));
     531
     532        else
     533        Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1));
     534       
     535end
     536
     537end
    489538
    490539end
     
    498547        "write some information";
    499548       
    500 EQUATIONS
     549PARAMETERS
     550
     551LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann");
     552
     553VARIABLES
     554
     555R               as positive;
     556P               as positive;
     557Pc              as positive;
     558Rho     as positive;
     559#Phi    as positive;
     560
     561EQUATIONS
     562
     563"Rho: Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
     564        Rho*(1-P*R) = (1-P);
     565
     566"Capacity Ratio for LMTD Correction Fator"
     567        R*(Outlet.Cold.T - Inlet.Cold.T ) = (Inlet.Hot.T-Outlet.Hot.T);
     568
     569"Non - Dimensional Variable for LMTD Correction Fator"
     570        P*(Inlet.Hot.T- Inlet.Cold.T)= (Outlet.Cold.T-Inlet.Cold.T);
     571       
    501572"Temperature Difference at Inlet"
    502573        DT0 = Inlet.Hot.T - Outlet.Cold.T;
     
    505576        DTL = Outlet.Hot.T - Inlet.Cold.T;
    506577       
    507 "LMTD Correction Factor"
    508         Fc = HE.FshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
     578if R equal 1
     579       
     580        then
     581        Pc*(2-P)= P;
     582       
     583        Fc= (sqrt(2)*Pc)/((1-Pc)*ln( abs( ( 2-Pc*0.585786)/( 2-Pc*3.414214))));
     584       
     585        else
     586        Pc = (sqrt(abs(( 1-P*R)/(1-P)))-1)/(sqrt(abs(( 1-P*R)/(1-P)))-R);
     587        Fc =sqrt(R*R+1)*ln(abs((1-Pc*R)/(1-Pc)))/((1-R)*ln( abs( ( 2-Pc*(R+1-sqrt(R*R+1)))/ ( 2-Pc*(R + 1 + sqrt(R*R+1))))));
     588       
     589end
     590
    509591
    510592end
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