Project 1 - Parsing NASA thermodynamic data

PARSING NASA THERMODYNAMIC DATA

AIM

To read and calculate the specific heat,enthalpy,entropy from all the species from the given NASA thermodynamic data file.

OBJECTIVES

1) To write a function that extracts the 14 co_efficients (a1-a14) and calculate the specific heat,enthalpy,entropy .

2) To plot the cp,enthalpy and entropy for the local temparature range of each species.

3) Saving the plots as images with corresponding species name and dumping them in separate folders for each species with suitable name.

INTRODUCTION

FILE PARSING

This challenge having a NASA thermodynamic data file,inorder to read the data file line by line and for calculating the required parameters , evaluation

of the polynomial,we are using some MATLAB commands to extract the data and evaluate,this process of parsing the data to obtain the objectives

is called as file parsing.

COMMANDS USED

fopen - this command is used to open the data file from the folder

fgetl - used to read the required data and also to skip the data

strsplit - string splitting, used to split the string in to number of words

str2num - string to number, used to convert the string in to numbers

strfind / findstr - used to find the letter or a number in the data

mkdir - used to create a folder

saveas - used to save the plots as images

NOTE* these are the new learned commands used here

CODE

clear all
close all
clc
% for getting the data file
f1=fopen('THERMO.dat','r');
fgetl(f1);
% reading the first line of the file
header_global_temp=fgetl(f1);
A=strsplit(header_global_temp,' ') ;       % splitting the string

%obtaining global max,medium and minimum temp:

global_min=strsplit(A{2});
global_mid=strsplit(A{3});
global_max=strsplit(A{4});

%ignoring the comments in the file
for i=1:3
    fgetl(f1);
end
% reading all line data
for i=1:53
    header=fgetl(f1);
    species_header=strsplit(header,' ');
    species_name=species_header{1};

%finding the string
    loc_temp=strsplit(header,' ');
    speciess_name=(loc_temp(1));
    loc_min_temp=str2double(loc_temp(end-3));
    loc_med_temp=str2double(loc_temp(end-2));
    loc_max_temp=str2double(loc_temp(end-1));

    %finding the coefficients a1 to a14
    tline1=fgetl(f1);
    tline2=fgetl(f1);
    tline3=fgetl(f1);
    

    a=strfind(tline1,'E');
    a1=tline1(1:a(1)+3);
    a1=str2double(a1);

    a2=tline1(a(1)+4:a(2)+3);
    a2=str2double(a2);

    a3=tline1(a(2)+4:a(3)+3);
    a3=str2double(a3);

    a4=tline1(a(3)+4:a(4)+3);
    a4=str2double(a4);


    a5=tline1(a(4)+4:a(5)+3);
    a5=str2double(a5);

 % finding strings and convert to numbers in line3
    a=strfind(tline2,'E');

    a6=tline2(1:a(1)+3);
    a6=str2double(a6);

    a7=tline2(a(1)+4:a(2)+3);
    a7=str2double(a7);

    a8=tline2(a(2)+4:a(3)+3);
    a8=str2double(a8);

    a9=tline2(a(3)+4:a(4)+3);
    a9=str2double(a9);

    a10=tline2(a(4)+4:a(5)+3);
    a10=str2double(a10);

    %finding strings and convert to numbers in line4

    a=strfind(tline3,'E');
    a11=tline3(1:a(1)+3);
    a11=str2double(a11);

    a12=tline3(a(1)+4:a(2)+3);
    a12=str2double(a12);

    a13=tline3(a(2)+4:a(3)+3);
    a13=str2double(a13);

    a14=tline3(a(3)+4:a(4)+3);
    a14=str2double(a14);

    % creating folder
    mkdir(['C:\Users\vaish\OneDrive\Desktop\NASA\images\',species_name]);

    
    



T=linspace(loc_min_temp,loc_max_temp,1000);
R=8.314;
%for getting the array of cp,h.and s
for k=1:length(T)
    % TO compare the temparature to assign the coefficients
    %a1-a7 is high temparature coefficients
    %a8-a14 is low temp coefficients
    if T(k)>loc_med_temp
        % high temparature coefficients 
        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;
    else
        %low temparature coefficients
        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;

    end

end
 
 %for i=1:53
     %loc_temp=strsplit(tline1,' ');
    %species_name=(loc_temp(1));

 % plotting the curves
 %cp v/s T
 figure(1);
 plot(cp,T,'LineWidth',3,'Color','r');
 grid on
 title(species_name);
 xlabel('specific heat [j/k]');
 ylabel('temparature [k]');
 saveas(1,'cp_vs_temp.jpeg');

 % H v/s T
 figure(2);
 plot(H,T,'LineWidth',3,'Color','b');
 title(species_name);
 xlabel('Enthalpy [j]');
 ylabel('temparature [k]');
 

 % entropy v/s  temparature
 figure(3);
 plot(S,T,'LineWidth',3,'Color','g');
 title(species_name);
 xlabel('Entropy  [kj-1/mol]');
 ylabel('temparature [k]');
 
 

% changing the directory and saving the file
saving=(['C:\Users\vaish\OneDrive\Desktop\NASA\images\',species_name]);
cd(saving)
saveas(1,'cp_vs_temp.jpeg');
saveas(2,'enthalpy_vs_temp.jpeg');
saveas(3,'entropy_vs_temp.jpeg');
end

CODE EXPLANATION

SCREENSHOT OF THE SAVED FOLDER FOR EACH SPECIES

OBJECTIVE : calculate the molecular weight of each species and display it in the command window.

CODE

function[w]=mol_weight(species_name)
atomic_names=['H','C','O','N','A'];
atomic_weights=[1,12,16,14,40];
w=0;
for i=1:length(species_name)
    for j=1:length(atomic_names)
    
    if strcmpi(species_name(i),atomic_names(j))
        w=w+atomic_weights(j);
        pos=j;
    end
    n=str2num(species_name(i));
    end
    if n>=1
        w=w+atomic_weights(pos)*(n-1);
        k=fprintf('Molecular weight of %s = %f',species_name,w);
    end
end

• A function is created to calculate the molecular weight of each species
• then calling the function in the main code to obtain the need for all those species.
• calculate the molecular weight of each species and displayed it in the command window.

NOTE* CODE for calling the function of molecular weight

mole_weight=mol_weight(species_name)

CONCLUSION

The required data is read using MATLAB by extracting the given NASA thermodynamic data file and programmed to plot the

enthalpy,entropy,specific heat for all 53 species.

the molecular weight is also calculated for all species.