You should look up characters and if-statements in the documentation.
clc;
clear;
%This function is will determine the rate of heat loss
%you will experience through one of our select pipes and
%piping insulation
pipe="stainless steel";%questdlg('Choose your pipe material','Pipe Material','copper','stainless steel','aluminum', 'aluminum');
insulation="glass wool";%questdlg('Choose your type of insulation','insulation','glass wool','rigid foam','no insulation','no insulation');
%Below are the inputs for the pipe dimensions
inner=100;%input('Enter pipe inner diameter in mm:');
thickness=5;%input('Enter pipe thickness in mm:');
ithickness=10;%input('Enter insulation thickness in mm:');
L=1;%input('Enter pipe length in m:');
%The below section handles temperatures. All temps calculated within
%fuction are calculated using celcius.
t2=25;%input('Enter approximate room temperature(Temperature outside of pipe and insulation):');
fprintf('This next input will be related to steam temperature. Enter either a single value or \nrange of values.\n')
fprintf('If entering a range of values, enter as a vector with incrementally equal values \nranging from 200 to 500 degrees celcius or 392 to 932 degrees Farenheit.\n')
%pause(3)
t1=450;%input('Input temperature of steam:');
unit="C";%questdlg('Are the temperatures you entered in celcius or farenheit?','Temp Unit','F','C','C');
if unit=="F"
T1=(t1-32)*5/9;
T2=(t2-32)*5/9;
elseif unit=="C"
T1=t1;
T2=t2;
end
if T1 > 500 | T1 < 200
disp('Please enter a temperature between 200C and 500C')
%pause(3)
%tempfunction()
end
%The section below handles the coefficients of heat transfer for the
%equation to solve.
if pipe=="copper"
if T1 >= 200 & T1 <= 350
k = 386;
elseif T1 >= 351 & T1 <= 500
k = 379;
end
elseif pipe=="stainless steel"
k=50 ; %W/m K
elseif pipe=="aluminum"
if T1>=200 & T1<=350
k = 159;
elseif T1>=351 & T1<=450
k = 172;
elseif T1>450
k=185;
end
end
if insulation=="glass wool"
k2=.05;
elseif insulation=="rigid foam"
k2=.02;
elseif insulation=="no insulation"
k2=0;
end
%heat transfer coefficient inside the pipe = 60 W/m^2*K(From
h1=60;
%heat transfer coefficient outside the pipe = 18 W/m^2*K
h2=18;
%To get radii
r1=inner/2;
r2=(inner/2)+thickness;
r3=(inner/2)+thickness+ithickness;
%Now we will calculate the surface areas exposed to convection
A1=2*pi*r1*L;
A2=2*pi*r2*L;
%Now we will calculate the individual thermakl resistance network
Rconv1=1/(h1*A1);
R1=log(r2/r1)/(2*pi*k*L);
R2=log(r3/r2)/(2*pi*k2*L);
Rconv2=1/(h2*A2);
fprintf('Here are the values for your thermal resistance network')
%pause(2);
fprintf('Rconv1= %6.3f C/W\n',Rconv1);
%pause(2);
fprintf('R1= %6.3f C/W\n', R1);
%pause(2);
fprintf('R2= %6.3f C/W\n',R2);
%pause(2);
fprintf('Rconv2= %6.3f C/W\n',Rconv2);
%Now we will add up the total thermal resistance
R=Rconv1+R1+R2+Rconv2;
%pause(5);
fprintf('Your total thermal resistance is %6.3f C/W.\n',R);
%Calculate the rate of heatloss
Qdot=(T1-T2)/R; %W
%pause(3);
fprintf('Your rate of heat loss through our pipe, as spec''d, will\nbe %6.3f W per meter of pipe.\n',Qdot);
%pause(3);
Qtotal=Qdot*L;
fprintf('Total heat loss through the pipe will be %6.3f W.\n', Qtotal);
Tdrop=Qdot*R1;
fprintf('The drop in temperature along the pipe will be %6.3f degrees C.\n',Tdrop);
figure(1)
plot(Qdot,T1,'bs:');
title('Qdot verses T1');
xlabel('Qdot');
ylabel('T1');
