Program to parse the NASA file and to plot the required graphs

AIM

To write the program to parse the file and to calculate the entropy , enthalpy , specific heat and molecular weight of the given elements.

Introduction:

Enthalpy:

Enthalpy (H) is the sum of the internal energy (U) and the product of pressure and volume (PV) given by the equation: H=U+PV.

Entropy:

Entropy, the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work.

Specific heat:

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

Molecular weight:

The molecular mass (m) is the mass of a given molecule: it is measured in daltons (Da or u).

Enthalpy, entropy, molecular weight, and specific heat of given elements are calculated using the below formulea.

Formulae:

Program of parsing of NASA file is as below:

close all
clear all
clc
%rearing the thermo file
file = fopen('THERMO.dat','r') 
 
%Universal gas constant value
R =8.314;                            
 
%header
line1 = fgetl(file)       
 
%temperature values
line2 = fgetl(file)      
 
%comments for obtaining file
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})
 
%information fo the species
%using for loop
for i=1:20
    
    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 new folder for species
    mkdir(['E:\AKSHAY\SKILL LYNC\Matlab_skill_lync\projects\Species\',species_name]);
 
    %Temperature ranges assumed 
    Temperature = linspace(300,5000,100); 
 
    %calculation of properties based on lower and higher temperatures
    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 graph
    %Temperature vs Entropy
    figure(1)
    plot(Temperature,S,'linewidth',3,'color','g')
    title(species_name)
    xlabel('Temperature')
    ylabel('Entropy')
 
    %Temperature vs Enthalpy
    figure(2)
    plot(Temperature,H,'linewidth',3,'color','r')
    title(species_name)
    xlabel('Temperature')   
    ylabel('Enthalpy')
 
    %Temperature vs Specific heat
    figure(3)   
    plot(Temperature,Cp,'linewidth',3,'color','b')
    title(species_name)
    xlabel('Temperature')
    ylabel('Specific heat')
 
    directory = (['E:\AKSHAY\SKILL LYNC\Matlab_skill_lync\projects\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('E:\AKSHAY\SKILL LYNC\Matlab_skill_lync\projects\')       %switching the directory back to read thermodat file for molecular mass calculation
 
    [MW] = molecular_weight(species_name)
 
end
 
fclose(file)

function for molecular weight is defined which is as given below:

%defining fuction to calculate molecular weight
function [MW] = molecular_weight(species_name)
  
        species = upper(species_name); 
 
    Constituents = ['H', 'C', 'N', 'O', 'A'];
 
    Atomic_weight = [1.00794 12.0107 14.0067 15.9994 39.948]; 
 
    MW = 0; %initial
 
    for i=1:length(species)
        for j=1:length(Constituents)
            if strcmp(species(i),Constituents(j))
                MW = MW + Atomic_weight(j); 
                u = j;
            end
        end
        n = str2num(species(i));
        if n>1
            MW = MW + Atomic_weight(u)*(n-1);
        end
    end
end

Explanation for the program:

file parsing is done using fopen(), fgetl(), fclose() commands. plot for various elements is done using for loop . where the molecular function is defined using for loop. plots of all the elements are saved into a single file. the screenshot of the window is shown below.

figure: screenshot of the window

plots of the elemet O2,CO2 are shown below:

Result:

The program is written to calculate the enthalpy,entropy,specific heat and molecular weight are calculated. The plots of all the species are saved and the required plots are shown above.