using fsolve with matrix

Question

Rodrigo Blas 2020-5-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/523686-using-fsolve-with-matrix

回答： Walter Roberson 2020-5-7

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

I would like to calculate xeq using fzero

xeq should be a vector.

T and Y is a vector.

function ydot=Zazarian_f_5(~,x)
X=x(1); y=x(2); T=x(3);
% given & calculation
T0=325;
Ta=300;
Fa0=5;
Fb0=10;
Fi0=10;
Ca0=0.2;
Cp_a=20;
Cp_b=20;
Cp_c=20;
Cp_i=18;
alpha=0.00015;
k1=0.0002;
Ua=320;
pb=1400;
e=25000;
mc=18;
thb=2;
thi=2;
delta_Hrx=-20000;
Cp_cool=18;
r=1.987;
kc1=1000;
%calculation
k2=k1*exp((e/r)*((1/300)-(1/T)));
Kc2=kc1*exp((-delta_Hrx/r)*((1/305)-(1/T)));
CA=Ca0*(1-X)*y*(T0/T);
CB=Ca0*(1-X)*y*(T0/T);
CC=Ca0*(1+2*X)*X*y*(T0/T);
Ci=2*Ca0*y*(T0/T);
ra=-k2*((CA*CB)-((CC^2)/Kc2));
ydot(1)=(-ra)/(Fa0);
ydot(2)=(-alpha/(2*y))*(T/T0);
ydot(3)=(-delta_Hrx*ra)/(Fa0*(Cp_a+(thb*Cp_b)+(thi*Cp_i)));
ydot = ydot';
end
%%Script:
clear all
clc
y0=[0 1 325]; % why a initial pressure drop of 1
W=[0 1000];
r=1.987;
kc1=1000;
Tkc1 = 305;
T0=325;
delta_Hrx=-20000;
% X vs W
[t,y]=ode45(@Zazarian_f_5, W, y0);
Teq = y(:,3);
Y=y(:,2);
X = y(:,1);
T = T0 + (X*delta_Hrx)/(60);
% Temperature vs W
figure
plot(t, T);
%using other guys
%plot(t, y(:,3));
xlabel('catalyst weight in kg');
ylabel('Temperature');
legend('T');
title('Temperature');
% step 2 Kc -- equilibrium constant equation at a t
xo=0;
%Kc2=kc1*exp((-delta_Hrx/r)*((1/305)-(1/T)));
Ca0=0.2;
KC=kc1*exp((-delta_Hrx/r)*((1/Tkc1)-(1./Teq)));
CA=@(xeq)Ca0*(1-xeq).*Y*(T0./Teq);
CB=@(xeq)Ca0.*(1-xeq).*Y.*(T0./Teq);
CC=@(xeq)Ca0*(1+2.*xeq).*Y.*(T0./Teq);
myfun=@(xeq) CC(xeq).^2./(CA(xeq).*CB(xeq))-KC;
XEQ=fzero(myfun,xo);
Error using fzero (line 306)
FZERO cannot continue because user-supplied function_handle ==> @(xeq)CC(xeq).^2./(CA(xeq).*CB(xeq))-KC failed with the
error below.
 Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of
 rows in the second matrix. To perform elementwise multiplication, use '.*'.
Error in zzz (line 41)
XEQ=fzero(myfun,xo);
 
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