File parsing using NASA thermodynamic DATA

Aim:

To write a function that extracts the 14 coefficients and calculates the enthalpy, entropy and specific heats for all the species in the data file

Explanation:

• Claiming the Universal Gas constant R as input.
• In order to get the temperature values, first open the file using 'fopen' to load the file from the directory.
• 'fgetl' is used to get the values of the temperature.
• The next is to find the low and high-temperature values for which 'linspace' is used.
• Then each species is saved in a variable 'species_N'.
• Two different coefficients are created using 'strfind' where now is for high-temperature coefficient and another for low-temperature coefficient.
• The different functions for different variables like Specific heat, enthalpy, entropy, and molecular weight are coded and called in the main program.

Theoretical definitions:

File Parsing:

Parsing a file means reading a data stream of some sort and building an in-memory model of the semantic content of data. This aims at facilitating performing some kind of transformation on data, It means to a computer "reading text" means to a human being. if we scan it, from start to finish and figure out what it means as you go - whether you're a person reading text or a computer parsing a file.

Specific Heat:

The specific heat is the amount of heat per unit mass required to raise the temperature by one-degree celsius.

Enthalpy:

Enthalpy is a thermodynamic property of a system. It is the sum of the internal energy added to the pressure and volume of the system. It reflects the capacity to do non-mechanical work and the capacity to release the heat. Enthalpy is denoted as H; specific enthalpy denoted as h.

Entropy:

The entropy of an object is a measure of the amount of energy that is unavailable to do work. Entropy is also a measure of the number of possible arrangements the atoms in the system can have. In this sense, entropy is a measure of uncertainty or randomness.

Molecular weight:

The average mass of a molecule of a compound compared to ¹/₁₂ the mass of carbon 12 and calculated as the sum of the atomic weights of the constituent atoms.

Atomic mass:

An atomic mass (symbol: m_a) is the mass of a single atom of a chemical element. It includes the masses of the 3 subatomic particles that make up an atom: protons, neutrons, and electrons. Atomic mass can be expressed in grams.

Equations:

Empirical equation given to find the thermodynamic properties are,

Where,

Cp = Specific Heat(J/(K kg)).

Universal gas constant R=8.314 J / (mol:K).

H=Enthalpy(J).

S=Entropy(J/K).

T= Temperature(K).

Program:

Primary program for executing the functions and to work on given data:

clear all
close all
clc

% Input Details
% Gas Const(R)
R = 8.314;

% Data file
data = fopen('THERMO.dat', 'r');

% Header data file
fgetl(data);

% Datas on Global temperature
global_temp_range = fgetl(data);
a = strsplit(global_temp_range);
global_low_temp = 200;%str2double (a{2});
global_intermediate_temp = 1000;%str2double (a{3});
global_high_temp = 3500;%str2double (a{4});

temp = linspace(global_low_temp, global_high_temp, 400)

for i = 1:3
  fgetl(data)
end

for i = 1:53
  line1 = fgetl(data)
  A = strsplit(line1, ' ');
  species_N = (A{1});
  
  t2 = fgetl(data);
  t3 = fgetl(data);
  t4 = fgetl(data);
  
  j = strfind(t2, 'E');
  k = strfind(t3, 'E');
  l = strfind(t4, 'E');
  
  % For high temperature coefficients
  h1 = str2double(t2(1:j(1)+3));
  h2 = str2double(t2(j(1)+4:j(2)+3));
  h3 = str2double(t2(j(2)+4:j(3)+3));
  h4 = str2double(t2(j(3)+4:j(4)+3));
  h5 = str2double(t2(j(4)+4:j(5)+3));
  h6 = str2double(t3(1:k(1)+3));
  h7 = str2double(t3(k(1)+4:k(2)+3));
  
  
  % For low temperature coefficients
  n1 = str2double(t3(k(2)+4:k(3)+3));
  n2 = str2double(t3(k(3)+4:k(4)+3));
  n3 = str2double(t3(k(4)+4:k(5)+3));
  n4 = str2double(t4(1:l(1)+3));
  n5 = str2double(t4(l(1)+4:l(2)+3));
  n6 = str2double(t4(l(2)+4:l(3)+3));
  n7 = str2double(t4(l(3)+4:l(4)+3));
  h=[h1 h2 h3 h4 h5 h6 h7 n1 n2 n3 n4 n5 n6 n7];
  % Specific Heat Function
  [c_p] = specific_heat(h1,h2,h3,h4,h5,n1,n2,n3,n4,n5,R,temp,global_intermediate_temp);
%   
%   % Enthalpy
  [H] = enthalpy(h1,h2,h3,h4,h5,h6,n1,n2,n3,n4,n5,n6,R,temp,global_intermediate_temp);
%   
%   % Entropy
 [S] = entropy(h1,h2,h3,h4,h5,h6,h7,n1,n2,n3,n4,n5,n6,n7,R,temp,global_intermediate_temp);
%[H]=enthalp_func(h,1000,temp,R)
  mkdir(species_N);
  current_dir = pwd;
  cd(species_N);
 
  % Plotting
 figure(1)
  plot(temp, c_p, 'linewidth', 3, 'color', 'r');
  title(species_N)
  xlabel('TEMPERATURE');
  ylabel('SPECIFIC HEAT');

 
 
 figure(2)
  plot(temp,H,'linewidth', 3, 'color', 'g');
  title(species_N)
  xlabel('TEMPERATURE');
  ylabel('ENTHALPY');
 

 figure(3)
  plot(temp,S,'linewidth', 3, 'color', 'b');
  title(species_N)
  xlabel('TEMPERATURE');
  ylabel('ENTROPY');
 saveas(1,'Specific_heat.png')
  saveas(2,'Enthalpy.png')
  saveas(3,'Entropy.png')

  
  cd(current_dir);
  
  m_w(i)= molecular_weight(species_N);
  disp(m_w(i))
  
end

Function program for calculating Enthalpy:

% Function for Enthalpy
function [H] = enthalpy(h1,h2,h3,h4,h5,h6,n1,n2,n3,n4,n5,n6,R,temp,global_intermediate_temp)
  
  for i = 1:length(temp)
    
    if temp(i) >= global_intermediate_temp
      H =(h1 + (h2.*(temp./2)) + (h3.*(temp.^2./2)) + (h4.*(temp.^3./3)) + (h5.*(temp.^4./4)) + (h6./temp(i))).* R.*temp;
      
    else
      H = (n1 + (n2.*(temp./2)) + (n3.*(temp.^2./2)) + (n4.*(temp.^3./3)) + (n5.*(temp.^4./4)) + (n6./temp(i))).*R.*temp;
    
    end
  
  end

end

Function program for calculating the Entropy:

% Function for Entropy
function [S] = entropy(h1,h2,h3,h4,h5,h6,h7,n1,n2,n3,n4,n5,n6,n7,R,temp,global_intermediate_temp);
  for i = 1:length(temp)
    if temp(i) <= global_intermediate_temp
      S(i) = R.*((h1.*log10(temp(i))) + (h2.*temp(i)) + (h3.*(((temp(i)).^2)./2)) + (h4.*(((temp(i)).^3)./3)) + (h5.*(((temp(i)).^4./4))+h7));
     
    else
      S(i) = R.*((n1.*log10(temp(i))) + (n2.*temp(i)) + (n3.*(((temp(i)).^2)./2)) + (n4.*(((temp(i)).^3)./3)) + (n5.*(((temp(i)).^4/4))+n7));

    end
 
  end

end

Function program for calculating the Molecular weight:

% Function for Molecular Weight
  function [m_w] = molecular_weight(species_N)
  elements = {'H', 'C', 'O', 'N', 'A', 'S'};
  atomic_weight = [1.007, 12.011, 15.999, 14.006, 39.948, 32.064];
  
  m_w = 0
  
  for i = 1:length(species_N)
    for j = 1:length(elements)
      if strcmp(species_N(i), elements(j));
        m_w = (m_w + atomic_weight(j));
        p = j;
      end
      end
    q = str2double(species_N(i));
    
    if q>1
      
      m_w = m_w + atomic_weight(p)*(q-1);
    
    end
      end
  end

Function program for calculating the specific_heat:

% Function for Specific Heat
function [c_p] = specific_heat(h1,h2,h3,h4,h5,n1,n2,n3,n4,n5,R,temp,global_intermediate_temp);
  for i = 1:length(temp)
    
   
    if temp(i) <= global_intermediate_temp
      c_p(i) = R*(h1+(h2*temp(i)) + (h3*(temp(i)).^2) + (h4*(temp(i)).^3) + (h5*(temp(i)).^4));
      
    else 
      c_p(i) = R*(n1+(n2*temp(i)) + (n3*(temp(i)).^2) + (n4*(temp(i)).^3) + (n5*(temp(i)).^4));

    end
  
    end

    end

PLOTS:

Not able to show all the plots here are the two example plots and all the plots folder are taken as a screenshot and displayed below.

HCOOH:

O2:

Proof:

I have run this program in GUI Octave and the below image shows the execution of the program

Result:

Finally, the program is executed and the required results are obtained.