Code keeps running without any error but no result ,please help!

Dear All,

I have a function named (Untitled) and a script named (Untitled2). I use the function in the script by calling it. Now, I have a problem and the problem is when I run the script it keeps running for a long time without showing any error, warning or result. I think something does not make sence in the code which this causes this problem, I tried to figure it ou but I coud not. It would be appreciated if you guys help me.

%%%% Function

function dz = Untitled (V, z, Ca0, Fa0, Cp0, Cpc, Ua, m, T1, T2, k1, K2, E, R, dH, hx)

% z(1)=Ta, z(2)=X, z(3)=T

k = k1*exp(E*(1/T1-1/z(3))/R);

Kc = K2*exp (dH* (1/T2 - 1/z (3))/R);

ra =-k*Ca0* (1 - (1 + 1/Kc)*z(2));

if hx == 'co', dz (1)= Ua* (z(3) - z(1))/(m*Cpc);

elseif hx =='cn', dz (1)= -Ua* (z (3) - z(1))/(m*Cpc);

else, dz(1) = 0;

end

dz (2) = -ra/Fa0; dz (3)= (ra*dH - Ua* (z (3) -z (1)))/(Fa0*Cp0);

dz = dz';

end

%%%%% Script

clear all;

Ca0= 1.86; Fa0= 14.67; T1 = 360; T2= 333; k1= 31.1; K2= 3.03;

E = 65700; R = 8.314; dH = -34500; Cp0= 141; Cpc= 28; Ua= 5000; m= 500;

hx ='cn'; %data and conditions

crit = 1e-2; Taf = 315; errT = 10; Vi= [0 5];

if hx =='cn' %guess Ta(z1)

Ta01 = 305; Ta02 = 320; Ta0m = (Ta01+Ta02)/2;

while errT >= crit

z01 = [Ta01 0 305];

z02 = [Ta02 0 305];

z0m= [Ta0m 0 305];

[V z1]=ode45 (@Untitled,Vi,z01,[],Ca0, Fa0, Cp0, Cpc, Ua,m, T1, T2, k1, K2, E, R, dH, hx);

[V zm] = ode45 (@Untitled,Vi, z0m,[],Ca0, Fa0, Cp0,Cpc, Ua, m, T1, T2, k1, K2, E, R, dH, hx);

[V z2] = ode45 (@Untitled, Vi, z02,[],Ca0, Fa0, Cp0, Cpc, Ua, m, T1, T2, k1, K2, E, R, dH, hx);

if (z1 (end, 1)-Taf)*(zm (end, 1)-Taf) < 0, Ta02=Ta0m;

Ta0m=(Ta01+Ta02)/2;

else, Ta01 = Ta0m;

Ta0m =(Ta01+Ta02)/2;

end

errt = abs (zm (end, 1)- Taf);

end

else

z0 = [310 0 305]; [V zm] = ode45 (@exbco, Vi, z0, [], Ca0, Fa0, Cp0, Cpc, Ua, m, T1, T2, k1, K2, E, R, dH, hx);

end

Ta =zm(:,1); X = zm(:, 2); T = zm (:, 3); k = k1*exp (E* (1/T1 - 1./T)/R); Kc= K2*exp(dH+ (1/T2 - 1./T)/R);

ra = -k*Ca0.*(1- (1+ 1./Kc).*X);

Xe = Kc./(1+Kc);

subplot (2,2,1), plot (V,T,V, Ta,'--'), xlabel ('V'), ylabel ('T(K)'),

legend ('T', 'T_a')

subplot (2,2,2), plot (V, X, V, Xe,'--'), xlabel('V'), ylabel ('X,X_e'),

legend ('X', 'Xe')

subplot (2,2,3), plot (V, -ra), xlabel ('V'), ylabel('-r_A')

fprintf('Conversion (X) and equilibrium conversion (Xe): Xf = %g, Xef = %g\n',X(end),Xe (end));

fprintf('Final T and Ta: Tf %g, Taf= %g\n', T(end), Ta (end)) ;

fprintf('Final reaction rate: raf = %g\n', -ra (end) );

Answer 1

[DGM]

If your code runs and doesn't indicate what it's doing, make it tell you what it's doing. For instance, store all the values of errt (the variable on which the exit condition depends). You might see a pattern that will tell you why it never terminates.

It never exits because it's not converging toward zero. You'll have to find out why. Maybe your initial conditions are landing you in some local minimum other than the one you intend -- or something like that. I don't know what problem you're trying to solve.