MATLAB: Matlab Plotting Question: No graphs

MATLABplotting

Hello Everyone, I am trying to plot the below equilibrium curve by using the plot shown. However, my code does not work.

Is there anything that I missed? Thank you for your help! 🙂

Best Answer

Hi, Meowooo

Please try below code.

T1 = 70:90;   A1 = 13.8858; B1 = 2788.51; C1 = 220.79;
T2 = 120:140; A2 = 14.0045; B2 = 3279.47; C2 = 213.20;
P = 101.33;
P1sat = exp(A1 - B1 ./ (T1 + C1));
P2sat = exp(A2 - B2 ./ (T2 + C2));
x1 = ((P - P2sat)./(P1sat-P2sat)); % / => ./
y1 = (P1sat/P).*x1; % * => .*
plot(x1, y1);
grid on

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MATLAB: Failure in initial objective function evaluation. FSOLVE cannot continue.

Ahmed, use the following:

fhandle = @Sample13;
options = optimset('display','off','Algorithm','levenberg-marquardt');
a       = 1:0.05:2;
for ii = 1:numel(a)
    X0      = [0.5,0.5,0.5,0.5,200,200,101.325,333.9,a(ii)];   
    X       = fsolve(fhandle,X0,options);
    disp(X)
end
function F = Sample13(X)
x1=X(1);
x2=X(2);
y1=X(3);
y2=X(4);
p1sat=X(5);
p2sat=X(6);
p=X(7);
t=X(8);
a = X(9);
f1 = p1sat-(exp(16.59158 -(3643.31/(t -33.424))));
f2 = p2sat-(exp(14.25326 -(2665.54/(t -53.424))));
f3 = p - 101.325;
f4 = x1 - a;
f5 = x1 + x2 - 1;
f6 = y1 + y2 - 1;
f7 = (y1*p)-(x1*p1sat);
f8 = (y2*p)-(x2*p2sat);
F=[f1;f2;f3;f4;f5;f6;f7;f8];
end

Essentially, you treat a as another function input.

MATLAB: How to write a code for iteration

After the first box, you write

deltaT = epsilon + 1; % so that the while loop is entered
while deltaT >= epsilon
    % put code of the second box here
    deltaT = % add equation for new updated value of deltaT
 end

Best Answer

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MATLAB: Failure in initial objective function evaluation. FSOLVE cannot continue.

MATLAB: How to write a code for iteration

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