I want to do the calculations in the for loop for each diameter, D value, and then draw the graph for each result, but with this code, I calculate one value and only one value appears in the graph. Where am I doing wrong? Sorry I'm beginner in mtlab

L=(2000+(5*50))

T=5+5*0.25

It=0.0075*L

ht=0.15*T

bt=0.50*It

e=0.0003*(5+50)

t=15000/sqrt(9.81/ht)

V=It*ht*bt

flwrt=V/t

for D=0.1:0.01:0.5

v=4*flwrt/pi*D

Re=(v*D)/0.00000131

if Re<2300

disp('It is laminar flow')

elseif Re<4000

disp('It is transitition')

else

disp('It is turbulant flow')

end

valvecost=320+(D/25)*200

elbowcost=60+((D/25)*50)

pipecost=((2000+(5*50))/25)*1,5

f=1.325/(log10(e/D*3.7+5.74/Re^0.9))

hp=5+5*0.25+(v^2)/2*9.81*[f*(2000+5*50)/D+8.1]

Ppower=((9.81*1000*flwrt*hp)/1000)

pumpandmotorcost=3700+100*ht

electricitycost=(0.15*(t/3600)*Ppower)

yearelectric=electricitycost*730

plot(D,Ppower)

plot(D,ht)

end

Answer 1

[David Fletcher]

As a general guide have a look at:

L=(2000+(5*50));
T=5+5*0.25;
It=0.0075*L;
ht=0.15*T;
bt=0.50*It;
e=0.0003*(5+50);
t=15000/sqrt(9.81/ht);
V=It*ht*bt;
flwrt=V/t;
iteration=1;
for D=0.1:0.01:0.5
    v=4*flwrt/pi*D;
    Re=(v*D)/0.00000131;
    if Re<2300
        disp('It is laminar flow')
    elseif Re<4000
        disp('It is transitition')
    else
        disp('It is turbulant flow')
    end
    
    valvecost=320+(D/25)*200;
    elbowcost=60+((D/25)*50);
    pipecost=((2000+(5*50))/25)*1,5;
     f=1.325/(log10(e/D*3.7+5.74/Re^0.9));
    hp=5+5*0.25+(v^2)/2*9.81*[f*(2000+5*50)/D+8.1];
   
    Ppower(iteration)=((9.81*1000*flwrt*hp)/1000);
    
    
    pumpandmotorcost=3700+100*ht;
    electricitycost=(0.15*(t/3600)*Ppower);
    yearelectric=electricitycost*730;
    htVals(iteration)=ht;
    iteration=iteration+1;
end

plot(0.1:0.01:0.5,htVals)
hold on
plot(0.1:0.01:0.5,Ppower)

If you wish to retain the other loop variables from each iteration (valvecost, elbowcost, pipecost etc.) you will have to adopt a similar strategy tothat of Ppower.