Challenge

Project 1 - Parsing NASA thermodynamic data

PPrasanna Raj19 Nov 2021

MATLAB

Program to execute the Species of Specific heat, Enthalpy and Entropy from a THERMO.dat file.

clear all
close all
clc

f1 = fopen('THERMO.dat','r'); --- To open the .dat file

%skipping first 5 lines
for i = 1:5
fgetl(f1);

end

% reading all species
for i = 1:53

r = fgetl(f1); ---- Read the file
m = strsplit(r,' '); --- Split the line
species_name=(m{1});
z=length(m); --- Describes the length of the line

%temperature
local_low_temp=str2num(m{z-3}); --- Read the three different temperature
local_high_temp=str2num(m{z-2});
local_mid_temp=str2num(m{z-1});

temp1 = local_low_temp;
temp2 = local_mid_temp;
temp3 = local_high_temp;

%getting first line coefficient(a1-a5)
line_1 = fgetl(f1);
a = findstr(line_1,'E'); --- This code describes to find the string characters in the line_1
a1 = str2num(line_1(1:(a(1)+3))); --- change string to number and describes the range of a first coeff. a1
a2 = str2num(line_1(a(1)+4:(a(2)+3)));
a3 = str2num(line_1(a(2)+4:(a(3)+3)));
a4 = str2num(line_1(a(3)+4:(a(4)+3)));
a5 = str2num(line_1(a(4)+4:(a(5)+3)));

%getting second line coefficient(a6-a10)
line_2 = fgetl(f1);
t2 = findstr(line_2,'E');
a6 = str2num(line_2(1:(t2(1)+3)));
a7 = str2num(line_2(t2(1)+4:(t2(2)+3)));
a8 = str2num(line_2(t2(2)+4:(t2(3)+3)));
a9 = str2num(line_2(t2(3)+4:(t2(4)+3)));
a10 = str2num(line_2(t2(4)+4:(t2(5)+3)));

%getting third line coefficient(a7-a14)
line_3 = fgetl(f1);
t3 = findstr(line_3,'E');
a11 = str2num(line_3(1:t3(1)+3));
a12 = str2num(line_3(t3(1)+4:t3(2)+3));
a13 = str2num(line_3(t3(2)+4:t3(3)+3));
a14 = str2num(line_3(t3(3)+4:t3(4)+3));

%temperature range for all species
T = linspace(temp1,temp3,1000);

% universal gas constant
R = 8.314;

mkdir(['C:\Users\rajpr\Documents\MATLAB\nasa thermo\',species_name])

% to get array of specific heat, enthalpy and entropy
for k = 1:length(T)

% compare the species temperature to assign the coefficients
%a1-a7 - high temperature coefficients & a8-a14 - low temperature coefficients
if T(k)>temp2

% high temperature coefficients

Cp = (a1+a2.*T+a3.*T.^2+a4.*T.^3+a5.*T.^4)*R;
H = (a1+(a2.*T)/2+(a3.*T.^2)/3+(a4.*T.^3)/4+(a5.*T.^4)/5+(a6./T))*R.*T;
S = (a1.*log(T)+a2.*T+(a3.*T.^2)/2+(a4.*T.^3)/3+(a5.*T.^4)/4+a7)*R;

else
% low temperature coefficients
Cp = (a8+a9.*T+a10.*T.^2+a11.*T.^3+a12.*T.^4)*R;
H = (a8+(a9.*T)/2+(a10.*T.^2)/3+(a11.*T.^3)/4+(a12.*T.^4)/5+(a13./T))*R.*T;
S = (a8.*log(T)+a9.*T+(a10.*T.^2)/2+(a11.*T.^3)/3+(a12.*T.^4)/4+a14)*R;

end
end

%plotting the graph for temperature Vs specific heat,enthalpy & entropy of species

figure(1)
plot(T,Cp)
grid on
title(species_name)
xlabel('temperature')
ylabel('specific heat')

figure(2)
plot(T,H)
grid on
title(species_name)
xlabel('temperature')
ylabel('Enthalpy')

figure(3)
plot(T,S)
grid on
title(species_name)
xlabel('temperature')
ylabel('Entropy')

%change directory to save the file
cd(['C:\Users\rajpr\Documents\MATLAB\nasa thermo\',species_name])

saveas(1,'specific heat','jpg')
saveas(2,'Enthalpy','jpg')
saveas(3,'Entropy','jpg')

%molecular mass calculation
elements = ['H','C','O','N','A']
atomic_weight = [1.0079 12.0107 15.999 14.0067 39.948];
mol_mass = 0;
for L=1:length(species_name)
for M=1:length(atomic_weight)
if strcmp(species_name(L),elements(M))
mol_mass=mol_mass+atomic_weight(M);
position=M;
end
end

n=str2num(species_name(L));
if n>1
mol_mass=mol_mass+atomic_weight(position)*(n-1);
end
end
sprintf('Molecular Weight of %s:%f u',species_name,mol_mass)
end

fclose(f1) --- to close the file f1

Output:

The graph for all species saved in the folder as shown below: