Project 1 - Parsing NASA thermodynamic data

AIM

To write a function that extracts the 14 co-efficients and to calculate the enthalpy, entropy and specific heats for all the species in the given NASA data file. And to calculate the molecular weight of each species and display it in the command window. And to plot the Cp, Enthalpy and Entropy for the local temperature range specific for each species given in the data file.

OBJECTIVE

Main objective of this project is to read the given NASA data file and to get the 14 coefficients for each species and to calculate the Specific heat, Enthalpy, Entropy with referring to the below formula. And to plot graphs of Cp,h,s vs temperature for each specimens and to save it in their alloted files.

FORMULAE

PROGRAM DESCRIPTION

• First the NASA thermodynamic data file is downloaded.
• Then the program is started with fopen command to read the data file.
• Then using the fgetl command the lines in the data file are get in the program.
• The three main global temperatures were given in the second line in the data file. Those temperatures were get in the command and assigned it as global min, mid, max temperature.
• Then using for loop the further operations were carried out.
• There are 53 species in total and each species has 14 coefficients under them.
• 14 coefficients were extracted in the main program and 3 function program programs were written to calculate Specific heat, Enthalpy, Entropy for all the species in the data file. First 7 coefficients are HIGH - Temperature coefficients and second 7 coefficients were LOW - Temperature coefficients.
• And those function program were called in the main program.
• And graphs were plotted for all the species of Cp vs T, h vs T, s vs T and all the graphs were saved using saveas command.
• And all the plots were saved as images with appropriate names and dump them in separate folders for each species with suitable name. All these should be generated automatically.
• And another function program is written to calculate molecular weight for all the 53 species.
• And that function program is called in the main program and molecular weight of the each species were displayed in the command window.

NEW COMMANDS LEARNED IN THIS PROGRAM

1. fopen : This command is used to open the file and here 'r' is used to read the data file.
2. fgetl : This command is used to get the lines from the data file.
3. strsplit : This command is used to split the group of words into seperate words.
4. str2num : Thsi command is used to convert the string into numbers for further operations.
5. strfind : This command is used to find a letter in the line.
6. mkdir : This command is used to make a new folder.
7. saveas : This command here is used to save the plots as images.

MATLAB CODES

Function program for calculating Specific heat

%function program for Specific Heat


function[Cp] = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,R,temp,global_mid_temp)

if temp >= global_mid_temp

    Cp = R*(a1+(a2*temp)+(a3*(temp).^2)+(a4*(temp).^3)+(a5*(temp).^4));
else
   Cp = R*(a8+(a9*temp)+(a10*(temp).^2)+(a11*(temp).^3)+(a12*(temp).^4));

end
end

Function program for calculating Enthalpy

%function program for Enthalpy


function[h] = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,R,temp,global_mid_temp)  %function name and input values

if temp >= global_mid_temp

    h = R.*temp.*(a1+(a2.*(temp./2))+(a3.*(temp./3))+(a4.*(temp./4))+(a5.*(temp./5))+(a6.*(temp./6)));
else
     h = R.*temp.*(a8+(a9.*(temp./2))+(a10.*(temp./3))+(a11.*(temp./4))+(a12.*(temp./5))+(a13.*(temp./6)));

end
end

Function program for calculating Entropy

%function program for Entropy


function [s] = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,R,temp,global_mid_temp)

if temp >= global_mid_temp

    s = R.*(a1.*log(temp) + (a2.*temp) + (a3.*(((temp)./2)./2)) + (a4.*(((temp)./3)./3)) + (a5.*(((temp)./4)./4)) + a7);
else
    s = R.*(a8.*log(temp) + (a9.*temp) + (a10.*(((temp)./2)./2)) + (a11.*(((temp)./3)./3)) + (a12.*(((temp)./4)./4)) + a14);

end
end

Function program for calculating Molecular weight

%function program for calculating Molecular weight

function[Mw] = Molecular_weight(Species_name)

element = {'H' 'C' 'N' 'O' 'Ar'};   %elements    
atomic_weight = [1.00784 12.0107 14.0067 15.999 39.948];    %Atomic weights

Mw=0;

for i = 1:length(Species_name)  %To calculate molecular weight for loop is used
    
    for j = 1:length(atomic_weight)
        if strcmp(Species_name(i), element(j));
        Mw = Mw + atomic_weight(j);
        
        u = j;
        
        end
        
    end
    
    n = str2num(Species_name(i));
    if n>1
        Mw = Mw + (atomic_weight(u)*(n-1));
    end
    
end
end

Main program

The above functions are called in the main program in order to complete the objectives.

clear all
close all
clc

f1 = fopen('THERMO.dat','r');   %To read the file
file_name = fgetl(f1);          %To get the first line of the file
line1 = fgetl(f1);              %To get the second line 
A = strsplit(line1,' ');        %To split and converting it to string


global_min_temp = str2num(A{2}); %To convert the string as number and assigning as global minimum temperature
global_mid_temp = str2num(A{3}); %To convert the string as number and assigning as global mid temperature
global_max_temp = str2num(A{4}); %To convert the string as number and assigning as global maximum temperature

for i = 1:3
    comments = fgetl(f1)        %To get the next three lines
end

for j = 1:53                                        
    species = fgetl(f1);        
    B = strsplit(species);
    Species_name = (B{1});
    
    line_1 = fgetl(f1);
    l1 = strfind(line_1,'E');
    a1 = str2num(line_1(1:(l1(1)+3)));
    a2 = str2num(line_1((l1(1)+4):(l1(2)+3)));
    a3 = str2num(line_1((l1(2)+4):(l1(3)+3)));
    a4 = str2num(line_1((l1(3)+4):(l1(4)+3)));
    a5 = str2num(line_1((l1(4)+4):(l1(5)+3)));

    line_2 = fgetl(f1);
    l2 = strfind(line_2,'E');
    a6 = str2num(line_2(1:(l2(1)+3)));
    a7 = str2num(line_2((l2(1)+4):(l2(2)+3)));
    a8 = str2num(line_2((l2(2)+4):(l2(3)+3)));
    a9 = str2num(line_2((l2(3)+4):(l2(4)+3)));
    a10 = str2num(line_2((l2(4)+4):(l2(5)+3)));
    
    line_3 = fgetl(f1);
    l3 = strfind(line_3,'E');
    a11 = str2num(line_3(1:(l3(1)+3)));
    a12 = str2num(line_3((l3(1)+4):(l3(2)+3)));
    a13 = str2num(line_3((l3(2)+4):(l3(3)+3)));
    a14 = str2num(line_3((l3(3)+4):(l3(4)+3)));
    
        
    R = 8.314;              %Gas constant
    temp = linspace(global_min_temp,global_max_temp, 100); %creating an array of temperature
    
    mkdir('C:\Users\Harri Prasanna\Documents\MATLAB\File Parsing\Species',Species_name) %Creating a folder
    
    Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,R,temp,global_mid_temp);        %Calling Specific heat function
    h = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,R,temp,global_mid_temp);       %Calling Entropy function
    s = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,R,temp,global_mid_temp);        %Calling Enthalpy function
    
    
    %plotting the graph between temp vs Cp
    figure(1)
    plot(temp, Cp, 'linewidth', 3 , 'color','k');   
    xlabel("Temperature")
    ylabel("Specific Heat")
    title(Species_name,'Specific Heat vs Temperature')
    grid on
    
    
    %plotting the graph between temp vs enthalpy
    figure(2)
    plot(temp, h, 'linewidth', 3 , 'color','g');    
    xlabel("Temperature")
    ylabel("Enthalpy")
    title(Species_name,'Enthalpy vs Temperature')
    grid on
    
    
    %plotting the graph between temp vs entropy
    figure(3)
    plot(temp, s, 'linewidth', 3 , 'color','r');    
    xlabel("Temperature")
    ylabel("Entropy")
    title(Species_name,'Entropy vs Temperature')
    grid on
    
    %creating folders for specific species name
    program = (['C:\Users\Harri Prasanna\Documents\MATLAB\File Parsing\Species\',Species_name]);
    cd(program)
    
    %Saving the figure
    saveas(figure(1),'Specific Heat.jpg')
    saveas(figure(2),'Enthalpy.jpg')
    saveas(figure(3),'Entropy.jpg')  
    
    cd('C:\Users\Harri Prasanna\Documents\MATLAB\File Parsing')
    
  
    
    Mw = Molecular_weight(Species_name);
    fprintf('Molecular weight of %s is %d',Species_name,Mw);    %To print the molecular weight of each element
    disp(' ')
end

fclose(f1)

With the calculated Cp, h and s values graphs were plotted for all the 53 species and saved in their appropriate files. here are the graphs plotted for

O2:

N2:

CO2:

SNAPSHOT OF COMMAND WINDOW

Snapshot of command window displaying the molecular weight of the all 53 species

SNAPSHOT OF THE FILES

53 Folders were created fro 53 species and the graphs were saved in their appropriate files.

ERRORS FACED

Semi-colons were missed in some lines which affectd in printing the molecular weight of the species in the command window.

Errors were faced during saving the plots as images and rectified later.

RESULTS AND CONCLUSION

A function that extracts the 14 co-efficients is written and the enthalpy, entropy and specific heats for all the species in the given NASA data file are calculated. And the molecular weight of each species are calculated and displayed it in the command window. The Cp, Enthalpy and Entropy for the local temperature range specific for each species given in the data file were plotted. These graphs for specific species are saved as image in their alloted folder.

From this project have learnt to open a data file and read using the commands and to get the lines form the file and using it calculations. And to make a directory and to change directory and to save the plotted graphs as images using saveas command.

REFERENCES

https://in.mathworks.com/help/matlab/ref/saveas.html

https://in.mathworks.com/matlabcentral/answers/403782-how-can-i-save-multiple-plots-in-a-specified-folder

https://skill-lync.freshdesk.com/support/solutions/articles/43000052923-common-problems-encountered-while-working-on-the-nasa-file-parsing-project