Parsing NASA thermodynamic data

Aim:

1. To extract all the coefficients of the species mentioned in the data file and calculate their parameters like enthalpy, entropy, and specific heat.
2. To plot the variation of these parameters for the specified local temperature range
3. To determine the molecular masses of the individual species mentioned in the data file.

Procedure:

1.) Initially open the given thermodynamic data file and read the data in the file and store the data to the variable F.

2.) Then read the header file of thermodynamic data and calculate the global low,mid and high temperature from the second line of header file.

3.) By using fgetl(), strsplit() and str2num() command find out the global low,mid and high temperatures in the second line.

4.) Then calculate the 14 coefficients for all the species in the given thermodynamic data file.

5.) In data file each species has three lines in which 14 coefficients are there.

6.) By using the for loop, calculate the 14 coefficients for all the species.

7.) By using strfind() command, find out the number of exponential in first line, by which we can find out the number of coefficient in first line.

8.) Once you find out, then convert the coefficient from string form to number form by using str2num() command.

9.) By doing the above steps for line two and three, we can calculate the 14 coefficients for all the species.

10.) Once you find out the coefficients for a species, then calculate the entropy,enthalpy and specific heat.

11.) First 7 coefficients are high temperature coefficients and calculate cp,H and s.

12.) Assuming universal gas constant R=8.314 J/mol-k and assuming temperature range from 100 to 5000 take 100 values by linspace() command.

13.) Once you calculate the entropy,enthalpy and specific heat for all the species, plot the graph between: Temperature vs Entropy, Temperature vs Enthalpy and Temperature vs Specific heat.

14.) Store all the three plots for all the species in the file. The stored file is shown in the above picture.

15.) Finally calculating the molecular weight for all the species and displayed in the command window.

16.) The method for calculating molecular weight is shown in the function program.

Code:

1. Primary Parsing Code:

close all
clear all
clc
%Opening and reading the required file
file = fopen(\'THERMO.dat\',\'r\')          

%Heading
line1 = fgetl(file)       

%Global temperature values
line2 = fgetl(file)      

%Next three lines are comments
des_1 = fgetl(file)                     
des_2 = fgetl(file)   
des_3 = fgetl(file)                     
A = strsplit(line2,\' \');
Global_low_temperature = str2num(A{2})
Global_mid_temperature = str2num(A{3})
Global_high_temperature = str2num(A{4})

%species information
for i=1:53
    
    species= fgetl(file);
    
    species_name = species(1:6)
    
Line_1 = fgetl(file);
    
L1 = strfind(Line_1,\'E\');

c1 = str2num(Line_1(1:(L1(1)+3)));

c2 = str2num(Line_1((L1(1)+4):(L1(2)+3)));

c3 = str2num(Line_1((L1(2)+4):(L1(3)+3)));

c4 = str2num(Line_1((L1(3)+4):(L1(4)+3)));

c5 = str2num(Line_1((L1(4)+4):(L1(5)+3)));


Line_2 = fgetl(file);

L2 = strfind(Line_2,\'E\');

c6 = str2num(Line_2(1:(L2(1)+3)));

c7 = str2num(Line_2((L2(1)+4):(L2(2)+3)));

c8 = str2num(Line_2((L2(2)+4):(L2(3)+3)));

c9 = str2num(Line_2((L2(3)+4):(L2(4)+3)));

c10 = str2num(Line_2((L2(4)+4):(L2(5)+3)));


Line_3 = fgetl(file);

L3 = strfind(Line_3,\'E\');

c11 = str2num(Line_3(1:(L3(1)+3)));

c12 = str2num(Line_3((L3(1)+4):(L3(2)+3)));

c13 = str2num(Line_3((L3(2)+4):(L3(3)+3)));

c14 = str2num(Line_3((L3(3)+4):(L3(4)+3)));

%creating folder for each species
mkdir([\'A:\\Users\\Athul\\File parsing NASA\\Species\\\',species_name]);

%Temperature ranges assumed for calculation purpose
Temperature = linspace(300,5000,100); 

%Universal gas constant
R =8.314;                            

%calculation of properties based on the lower and upper temperature
for j = 1:length(Temperature)
    if Temperature(j)<3000
Cp = (c1+c2.*Temperature+c3.*Temperature.^2+c4.*Temperature.^3+c5.*Temperature.^4).*R;
H = (c1+(c2.*Temperature)./2+(c3.*Temperature.^2)/3+(c4.*Temperature.^3)/4+(c5.*Temperature.^4/5)+c6./Temperature).*Temperature.*R;
S = (c1*log(Temperature)+c2.*Temperature+(c3.*Temperature.^2)/2+(c4.*Temperature.^3)/3+(c5.*Temperature.^4)/4+c7).*R;
    else
Cp = (c8+c9.*Temperature+c10.*Temperature.^2+c11.*Temperature.^3+c12.*Temperature.^4).*R;
H = (c8+(c9.*Temperature)/2+(c10.*Temperature.^2)/3+(c11.*Temperature.^3)/4+(c12.*Temperature.^4/5)+c13./Temperature).*Temperature.*R;
S = (c8.*log(Temperature)+c9.*Temperature+(c10.*Temperature.^2)/2+(c11.*Temperature.^3)/3+(c12.*Temperature.^4)/4+c14).*R;
    end
end

%plotting

%Temperature vs Entropy
figure(1)
plot(Temperature,S,\'linewidth\',4,\'color\',\'b\')
title(species_name)
xlabel(\'Temperature\')
ylabel(\'Entropy\')

%Temperature vs Enthalpy
figure(2)
plot(Temperature,H,\'linewidth\',4,\'color\',\'k\')
title(species_name)
xlabel(\'Temperature\')
ylabel(\'Enthalpy\')

%Temperature vs Specific heat
figure(3)
plot(Temperature,Cp,\'linewidth\',4,\'color\',\'y\')
title(species_name)
xlabel(\'Temperature\')
ylabel(\'Specific heat\')

directory = ([\'A:\\Users\\Athul\\File parsing NASA\\Species\\\',species_name]);   %changing the filepath to save the plots
cd(directory)

%saving the plots

saveas(1,\'Entropy.jpg\');
saveas(2,\'Enthalpy.jpg\');
saveas(3,\'Specific heat.jpg\');

cd(\'A:\\Users\\Athul\\File parsing NASA\\\')       %switching the directory back to read thermodat file for molecular mass calculation

MM = molecular_mass(species_name)

end

fclose(file)

2. Function to calculate the molecular masses of individual species:

function MM = molecular_mass(species_name)
  
species = upper(species_name); 

Constituents = [\'H\', \'C\', \'N\', \'O\', \'A\'];

Atomic_weight = [1.00794 12.0107 14.0067 15.9994 39.948]; 

MM = 0; 

for i=1:length(species)
    for j=1:length(Constituents)
        if strcmp(species(i),Constituents(j))
           MM = MM + Atomic_weight(j); 
           u = j;
        end
    end
    n = str2num(species(i));
    if n>1
        MM = MM + Atomic_weight(u)*(n-1);
    end
end
end

Images:

1. Location of species folder in desktop:

2. Molecular masses displayed in the command window:

Plots for O2:

Plots for N2:

Plots for CO2:

References:

https://www.engineeringtoolbox.com/carbon-dioxide-d_974.html

https://www.mathworks.com/help/matlab/ref/fgetl.html

https://physics.stackexchange.com/questions/153452/why-does-heat-added-to-a-system-at-a-lower-temperature-cause-higher-entropy-incr

Thank You.