Project 1 - Parsing NASA thermodynamic data

AIM:

To write a code for parse nasa thermodynamic data file and then calculate the thermodynamic properties for various gas species.

Objective:

1. Write a function that extracts the 14 coefficients and calculates the enthalpy, entropy, and specific heats for all the species in the data file
2. Calculate the molecular weight of each species and display it in the command window.
3. Plot the Cp, Enthalpy, and Entropy for the local temperature range (low temperature: high temperature) specific for each species.
4. Save the plots as images with appropriate names and dump them in separate folders for each species with a suitable name. All these should be generated automatically.
5. The main program that you will submit will just take the "THERMO.dat" file as an input and generate Cp, H, and S plots.

Theory:

File Parsing: Parsing a file means splitting a file or other input into a piece of data that can easily be stored or manipulated. we are splitting a string into parts then recognize the parts to convert it into something simpler than a string.

Enthalpy: A thermodynamic quantity equivalent to the total heat content of the system, i.e sum of internal energy and the product of pressure and volume for the system.

Entropy: A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.

Specific Heat: The heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree).

Molecular Weight: The ratio of the average mass of one molecule of an element or compound to one-twelfth of the mass of an atom of carbon-12.

Given equations for H, S, Cp:

where,

Cp is specific heat.

h is specific enthalpy.

s is specific entropy.

R is the universal gas constant.

T is the temperature in kelvin.

Coding for file parsing:

close all
clear all
clc

% file reading
f1 = fopen('THERMO.dat','r');
tline = fgetl(f1);
tline = fgetl(f1);
A = strsplit(tline,' ');
global_min_temp = str2double(A{2});
global_mid_temp = str2double(A{3});
global_max_temp = str2double(A{4});

% skip next three comments
for i = 1:3
    tline1 = fgetl(f1);
end

% reading the data
for j = 1:53 %loop for all element blocks
    
    header_line = fgetl(f1);
    a = strsplit(header_line,' ');
    species_name = a{1};
    B = strfind(header_line, 'G');
    temp_values = header_line(B+4:length(header_line)-5);
    C = strsplit(temp_values,' ');
    local_low_temp = str2double(C{1});
    local_mid_temp = str2double(C{3});
     local_high_temp = str2double(C{2});
     
     
     tline2 = fgetl(f1);
     D = strfind(tline2,'E');
     a1 = str2double(tline2(1:D(1)+3));
     a2 = str2double(tline2(D(1)+4:D(2)+3));
     a3 = str2double(tline2(D(2)+4:D(3)+3));
     a4 = str2double(tline2(D(3)+4:D(4)+3));
     a5 = str2double(tline2(D(4)+4:D(5)+3));
     
     tline3 = fgetl(f1);
     F = strfind(tline3,'E');
     a6 = str2double(tline3(1:F(1)+3));
     a7 = str2double(tline3(F(1)+4:F(2)+3));
     a8 = str2double(tline3(F(2)+4:F(3)+3));
     a9 = str2double(tline3(F(3)+4:D(4)+3));
     a10 = str2double(tline3(F(4)+4:F(5)+3));
     
      tline4 = fgetl(f1);
      G = strfind(tline4,'E');
      a11 = str2double(tline4(1:G(1)+3));
      a12 = str2double(tline4(G(1)+4:G(2)+3));
      a13 = str2double(tline4(G(2)+4:G(3)+3));
      a14 = str2double(tline4(G(3)+4:G(4)+3));
      
      T =linspace(local_low_temp,local_high_temp,500);
      R = 8.314;
for k = 1:length(T)
    
    if (T(k)>= local_mid_temp)
        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 
        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
      % create new folder
     mkdir(['C:\Users\DELL\Documents\MATLAB\HEV\Matlab\file parsing\',species_name]);
      
     % plots for all species
  
      figure(1);
      plot(T,Cp);
      title('specific heat');
      xlabel('Temperature');
      ylabel('Specific Heat');
      title(species_name)
      
      
       figure(2);
      plot(T,H);
      title('Enthalpy');
      xlabel('Temperature');
      ylabel('Enthalpy');
      title(species_name)
      
      
      figure(3);
      plot(T,S);
      title('Entropy');
      xlabel('Temperature');
      ylabel('Entropy');
       title(species_name)
       
      cd(['C:\Users\DELL\Documents\MATLAB\HEV\Matlab\file parsing\',species_name]); 
       
      saveas(1,'Cp vs T.jpg')
      saveas(2,'H vs T.jpg')
      saveas(3,'S vs T.jpg')
      
% calculating molecular mass

 atomic_mass = [1 12 14 16 40];
 elements = ['H','C','N','O','A'];
  molecular_weight = 0;
 for l = 1:length(species_name)
     for m = 1:length(elements)
         if strcmpi(species_name(l),elements(m))
     molecular_weight = molecular_weight+atomic_mass(m);
     z = m;
         end 
     end
    
 t = str2double(species_name(i));
if (t>1)
     
      molecular_weight = molecular_weight+(atomic_mass(z)*(t-1));
     
 end
 end
sprintf( '%s %d',species_name,molecular_weight)
end

Plots for o2, N2 and Co2 species:

Explanation:

1. Read and open the file of TERMO.dat using fopen command and syntax for fopen is fopen(filename,r), where r stands for reading the file.
2. read all the lines of the file one by one using fgetl command.
3. split the line from the space between the temperatures using strsplit command and the syntax for strsplit is strsplit(line,' '), where ' ' presenting the space between the temperatures.
4. now change a string into a number using the str2double command for global temperatures.
5. skip the next three comments by creating a for-loop.
6. creating another for-loop to read the coefficient data for 1st species and use fgetl command again for coefficient lines.
7. split the line from the space between the values using strsplit command and the syntax for strsplit is strsplit(line,' '), where ' ' presenting the space between the values.
8. create a variable named species_name for species.
9. use strfind command to find out the position of G in the coefficients lines.
10. create a variable for temperature and then split them using strsplit command and convert the string into a number using str2double for all values of local temperature.
11. now again use fgetl command three times one by one and find out all the coefficients for O2 but this is in for-loop so we will get coefficient for all species.
12. now divide the local min. temperature and local max. temperature into 500 parts using linspace command for variable T.
13. now create another for-loop for the length of variable T and find all values of Cp, H, S for every possible value of T.
14. use mkdir command for automatically creating the folder and the syntax is mkdir(folder name,file name).
15. plot for all species of specific heat, entropy, enthalpy using plot command and give titles to the plots using title command.
16. specify the file name using cd.
17. save all the plots using saveas command.

An explanation for molecular weight:

1. create for-loop for atomic mass and for elements.
2. now compare the species_name with elements using strcmpi command.
3. find out molecular weight using the standard formula (molecular weight = molecular weight+atomic mass).
4. if we have two elements together then use the formula molecular weight = molecular weight+atomic mass*(t-1), where t represents the no. of the same element more than one in the same molecule.
5. use sprintf command to display the species name and molecular weight together with the help of %s %d.

Molecular weight for each species in the command window:

Screenshot of the window where all the folders saved.