How to plot this function in chemical reactor

%%steady state plotting
T0=[290 298 305]; %%T -initial
Tr=270:1:370; %%T - range
figure
plot(Tr,mass_balance(Tr), Tr,energy_balance(Tr,T0))
hold on
plot(Tr,energy_balance(Tr,T0(3)), Tr, energy_balance(Tr,T0(2)), Tr,energy_balance(Tr,T0(1)))
hold off

function X=mass_balance(T)
VR=2000; %dm3 reactor volume
V=300; %l/min 
tr=VR/V; %
cao=4; %mol/l
cp=3.5; %J/g/K
rho=1150; %g/dm3
dHr=-50000; %J/mol
k=2.4e15.*exp(-12000./T); %
X=k*tr/(1+k*tr); %converse
end
function Xeb=energy_balance(T)
VR=2000; %dm3
V=300; %l/min
tr=VR/V; 
cao=4; %mol/l
cp=3.5; %J/g/K
rho=1150; %g/dm3
dHr=-50000; %J/mol
T0=[290 298 305];
k=2.4e15.*exp(-12000./T); 
Xeb=rho.*cp.*(T-T0)./((-dHr).*cao); %converse
end

%%And this is the solution, that i cant get it.. 

Could tell me please, how plotting this, i dont understand this. Thanks for your help.

[Scott MacKenzie]

May I suggest you put a bit more effort into writing and debugging your code before posting a question that amounts to "broken, please fix".

I did have a quick look at your code, however. Your function mass_balance was returning a scalar, not an arrary. I fixed that by adding dot notation where needed. So, this bit of code gets you part way to where you want to be:

plot(Tr,mass_balance(Tr));

function X=mass_balance(T)
VR=2000; %dm3 reactor volume
V=300; %l/min 
tr=VR/V; %
cao=4; %mol/l
cp=3.5; %J/g/K
rho=1150; %g/dm3
dHr=-50000; %J/mol
k=2.4e15 .* exp(-12000 ./ T); 
X=k .* tr ./ (1+k .* tr); % NOTE: dot notation needed
end

Good luck.

[Lenny Guitar]

God, stupid mistakes.. Thank you. But the real problem is, how to plot the energy balance, when this depend on T0. i wrote: plot(Tr, energy_balance(Tr,T0(1)), Tr,energy_balance(Tr,T0(2)), Tr, energy_balance(Tr,T0(3))); But still getting Error using plot Vectors must be the same length.

[Scott MacKenzie]

You need to do some more debugging here. For your plot command above, the x vectors are all Tr. That's fine. Try assigning the y values to variables:

y1 = energy_balance(Tr,T0(1));
y2 = energy_balance(Tr,T0(2));
y3 = energy_balance(Tr,T0(3));

and then insert those variables into plot as follows:

plot(Tr, y1, Tr, y2, Tr, y3);

You'll get the same error message ("Error using plot Vectors must be the same length"). So, have look at the length of the vectors. Are Tr and y1 the same length, as they must be? Your thinking should be something like... Hmm, Gee, Ah Ha, OK, Yes, I get it! Let's fix that.

Good luck