Project 1 - Parsing NASA thermodynamic data
Where,
Cp=specific heat
R =molar gas constant
T=temperature
S=Entropy
H=Enthalpy
a=coefficients
BODY OF THE CONTENT:
Code for calling function Specific_heat():
function Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp)
%calculating specific_heat for higher and lower temperature respectively
if(T>= global_midtemp)
Cp=R*(a1+(a2*T)+(a3*(T).^2)+(a4*(T).^3)+(a5*(T).^4));
else
Cp=R*(a8+(a9*T)+(a10*(T).^2)+(a11*(T).^3)+(a12*(T).^4));
end
end
Code for calling function Enthalpy( ):
function H = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,global_midtemp)
%calculating enthalpy for higher and lower temperature respectively
if(T>=global_midtemp)
H=R*((a1*T)+((a2*(T).^2)/2)+((a3*(T).^3)/3)+((a4*(T).^4)/4)+((a5*(T).^5)/5)+a6);
else
H=R*((a8*T)+((a9*(T).^2)/2)+((a10*(T).^3)/3)+((a11*(T).^4)/4)+((a12*(T).^5)/5)+a13);
end
end
Code for calling function Entropy( ):
function S=Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp)
%calculating entropy for higher and lower temperature respectively
if(T>= global_midtemp)
S=R*(a1.log(T)+(a2*T)+((a3(T).^2)/2)+((a4*(T).^3)/3)+((a5*(T).^4)/5)+a7);
else
S=R*(a8.log(T)+(a9*T)+((a10(T).^2)/2)+((a11*(T).^3)/3)+((a12*(T).^4)/4));
end
end
Code for calculating molecular weight by calling function wt( ):
function Molecular_weight=wt(species_name)
Elements=['H' 'C' 'O' 'N' 'A' 'S'];
Atomic_weight =[1 12 16 14 40 32];
species=upper(species_name)
Molecular_weight=0;
for i=1:length(species)
for j=1:length(Elements)
if strcmp(species(i),Elements(j))
Molecular_weight=Molecular_weight+Atomic_weight(j);
k=j;
else
n=str2double(species(i));
if (n>1)
Molecular_weight=Molecular_weight+Atomic_weight(k)*(n-1);
break
end
MAIN CODE:
clear all
close all
clc
%R=molar gas constant
R=8.314;
%syntax to open the file THERMO.dat
f1=fopen('THERMO.dat','r')
%To read lines
l1=fgetl(f1);
l2=fgetl(f1);
value=strsplit(l2,' ');
%To get global temperatures from file in number form
global_lowtemp=str2num(value{2})
global_midtemp=str2num(value{3})
global_hightemp=str2num(value{4})
%temperature range
T=linspace(global_lowtemp,global_hightemp,1000);
%skipping these 3 lines
l3=fgetl(f1);
l4=fgetl(f1);
l5=fgetl(f1);
%Reading species ,calcuating cp,h,s and plotting
for i=1:53
tline=fgetl(f1);
A=strsplit(tline,' ');
name_of_species=(A{1});
lowtemp= str2num(A{end-3});
midtemp=str2num(A{end-2});
hightemp=str2num(A{end-1});
%Finding 7 higher coefficients and 7 lower coefficients
tline1=fgetl(f1);
a=findstr(tline1,'E');
a1=tline1(1:a(1)+3);
a1=str2num(a1);
a2=tline1(a(1)+4:a(2)+3);
a2=str2num(a2);
a3=tline1(a(2)+4:a(3)+3);
a3=str2num(a3);
a4=tline1(a(3)+4:a(4)+3);
a4=str2num(a4);
a5=tline1(a(4)+4:a(5)+3);
a5=str2num(a5);
tline2=fgetl(f1);
a=findstr(tline2,'E');
a6=tline2(1:a(1)+3);
a6=str2num(a6);
a7=tline2(a(1)+4:a(2)+3);
a7=str2num(a7);
a8=tline2(a(2)+4:a(3)+3);
a8=str2num(a8);
a9=tline2(a(3)+4:a(4)+3);
a9=str2num(a9);
a10=tline2(a(4)+4:a(5)+3);
a10=str2num(a10);
tline3=fgetl(f1);
a=findstr(tline3,'E');
a11=tline3(1:a(1)+3);
a11=str2num(a11);
a12=tline3(a(1)+4:a(2)+3);
a12=str2num(a12);
a13=tline3(a(2)+4:a(3)+3);
a13=str2num(a13);
a14=tline3(a(3)+4:a(4)+3);
a14=str2num(a14);
%calculate specific heat(cp),Enthalpy(H),Entropy(S)
Cp=Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp);
H=Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,global_midtemp);
S=Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp);
%calculating molecular weight and printing it.
Molecular_weight=wt(name_of_species);
fprintf('molecular weight of %s= %f\n',name_of_species,Molecular_weight);
%PLOTTING CP,H,T
cd('C:\Users\hhh\Desktop\matlab\NASA FILES')
%creating the folder
mkdir(name_of_species);
cd(name_of_species);
%plotting T vs cp
figure(1)
plot(T,Cp,'linewidth',5,'color','r')
xlabel('Temperature(T)')
ylabel('Specific heat(cp)')
grid on
title(name_of_species)
saveas(figure(1),'specific heat.jpg');
%Plotting T vs H
figure(2)
plot(T,H,'linewidth',5,'color','b')
xlabel('Temperature(T)')
ylabel('Enthalpy(H)')
grid on
title(name_of_species)
saveas(figure(2),'Enthalpy.jpg');
%Plotting T vs S
figure(3)
plot(T,S,'linewidth',5,'color','y')
xlabel('Temperature(T)')
ylabel('Entropy(S)')
grid on
title(name_of_species)
saveas(figure(3),'Entropy.jpg');
cd('C:\Users\hhh\Documents\MATLAB\nasa files')
end
Explanation for code:
Initially the value of ‘R’ is being defined.
Then we use a command to open the file ‘THERMO.dat’ .
Further we use the ‘fgetl’ to start reading the lines and after reading the first two lines, from the second line converting the
strings to numbers and assigning global (low,mid and high) temperatures.
Then we have written a command to get the temperature range for calculation and plotting purpose.
Then again using the fgetl command to go to thel next 3 lines and skipping it.
Then we use a for loop to get 53 species and their temperatures (low, mid, high) and the 14 coefficients.
In the for loop we again use the fgetl command and then the next line is read and from that line the species name, the three
local temperatures are read and stored.
Then we use fgetl command to go to further line and get the first 7 coefficients and store them. Similarly using the fgetl
command we move to the next two lines and get the remaining coefficients.
Then after getting the 14 coefficients, we use these coefficients and by calling the functions we calculate cp,H,S.
Further we use the Molecular weight function and calculate molecular weight for that species.
Further I have used a command to change the directory so that I can save the files at a particular location.After changing the
directory I have used ‘mkdir' to create a new folder with the name of the current species and then a ‘cd’ command to make
mkdir as the current directory.
Then further we use plot command to plot temperature vs (cp,enthalpy,entropy) .
In this plotting we use the figure command to get the three different plots and saveas command to save the figures in the
Then again we change our directory to again start the loop. So the loop continues to function till we get all the 53 species
and then gets terminated.