Cannot get these errors to clear.

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Abby Revoir 2020-10-1

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/603430-cannot-get-these-errors-to-clear

评论： Abby Revoir 2020-10-2

在 MATLAB Online 中打开

>> solve_ODEs_CA3

Unrecognized function or variable 'Cto'.

Error in solve_ODEs_CA3/ODEs_CA3 (line 37)

CA = Cto*(Fa/Ft) * (To/T);

Error in odearguments (line 90)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in solve_ODEs_CA3 (line 4)

[V,y] = ode45(@ODEs_CA3,tspan,y0);

function solve_ODEs_CA3()
    tspan = (0:0.01:1);
    y0 = [100 0 0 423];
    [V,y] = ode45(@ODEs_CA3,tspan,y0);
    plot(V,y(:,1),'-o',V,y(:,2),'-o',V,y(:,3),'-o')
    title('Temperature Profile');
    xlablel('V(dm^3)');
    ylabel('t(k)');
    legend('F_A','F_B','F_C','T');
    
    function output = ODEs_CA3 (~,y)
        Fa = y(1);
        Fb = y(2);
        Fc = y(3);
        T = y(4);
        
        
       deltaH1 = -20000;
       deltaH2 = -60000;
       CPA = 90;
       CPB = 90; 
       CPC = 180;
       Ua = 4000;
       Ta = 373;
       ER1 = 4000;
       ER2 = 9000;
       T0 = 423;            %Setting values for first set of variables 
       
       %Eq. for K1A and K2A
       K1A = 10*exp(ER1*((1/300)-(1/T)));
       K2A = 0.09*exp(ER2*((1/300)-(1/T)));
        
       %Eq. for FT
       Ft = Fa + Fb + Fc;
       
       %Eq. for CA, CB, CC
       CA = Cto*(Fa/Ft) * (To/T);
       CB = Cto*(Fb/Ft)*(To/T);
       CC = Cto*(Fc/Ft)*(To/T);
       
       %Eq. for RA1 and RA2
       RA1 = -K1A*CA;
       RA2 = -K2A*(CA)^2;
       
       %Eq. for dFa, DFb, and Dfc derivatives
       dFAdV = RA1 +RA2;
       dFBdV = -RA1;
       dFCdv = -(1/2)*(-RA2);
       
       %Derivative of dT eq.
       dTdV = (Ua*(Ta-T)+(-RA1)*(deltaH1)+(-RA2)*(-deltaH2))/((Fa*CPA)+(Fb*CPB)+(Fc+CPC));
       
       ouput = [dFAdV;dFBdV:dFCdV;dTdV];
       size(output)
    end
       
end
       
       

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回答（1 个）

Cris LaPierre 2020-10-2

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/603430-cannot-get-these-errors-to-clear#answer_503806

Your equations for CA, CB, CC in ODEs_CA3 function use a variable Cto that has not been created or at least does not exist within the scope of that function. You either need to define it, or pass it in as input to the function.