why doesn't this matlab code work? HELP!!!

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0 个投票

My problem is that this code doesn't work and I need the graph. Help please.

clear all
clc;
es=0.007;%m
d=2800;%kg/m^3
k=180;%W/m K
E=0.8;
C=900;%J/kg K
Tamb=298;%K
As=0.04;%m^2
qh=12500; %W/m^2 K
h=10;%W/m^2 K
Tfp=408;%K
cteEB=5.67*10^-8;
V=0.00028;%m^3
to=0;
deltat=0.1;% seconds
t=[];
Tf=[];
while (Tfp>=Tf)
    Tf(i+1)=(As/(d*C*V))*(qh-(h*(Tf(i)-Tamb))-(E*cteEB*(Tf(i)^4-Tamb^4)))*deltat+Tf(i);
    t(i+1)=t(i)+deltat;
    hold on 
    plot(Tf,t);
    i=i+1;
end 
xlabel ('Temperature');
ylabel ('Time [s]');

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John D'Errico 2021-3-6

PLease do not provide a PICTURE of your code. That makes it virtually impossible for someone to easily help you, because they need to then type in your code by reading the code and then transcribing it character by character into MATLAB. And why would you possibly want to make it more difficult to get help?

Erika Abril 2021-3-6

在 MATLAB Online 中打开

clear all
clc;
es=0.007;%m
d=2800;%kg/m^3
k=180;%W/m K
E=0.8;
C=900;%J/kg K
Tamb=298;%K
As=0.04;%m^2
qh=12500; %W/m^2 K
h=10;%W/m^2 K
Tfp=408;%K
cteEB=5.67*10^-8;
V=0.00028;%m^3
to=0;
deltat=0.1;% seconds
t=[];
Tf=[];
while (Tfp>=Tf)
    Tf(i+1)=(As/(d*C*V))*(qh-(h*(Tf(i)-Tamb))-(E*cteEB*(Tf(i)^4-Tamb^4)))*deltat+Tf(i);
    t(i+1)=t(i)+deltat;
    hold on 
    plot(Tf,t);
    i=i+1;
end 
xlabel ('Temperature');
ylabel ('Time [s]');

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Answer 1

Walter Roberson 2021-3-6

编辑：Walter Roberson 2021-3-7

0 个投票

You did not initialize i so it will have its default value of sqrt(-1). Then inside the loop when you assign to Tf(i+1) that is a destination of 1+1i which is not a valid index.

For that code to work you need to initialize i to 1.