Challenge

Project 1 - Parsing NASA thermodynamic data

KKunal Das31 Jul 2021

Aim- To Parse the THERMO.dat file and calculate enthalpy,entropy,specific heat and plot their graphs against temperature and store them in individual folders.

Theory-The process of "parsing" can be described as reading in a data stream of some sort and building an in-memory model or representation of the semantic content of that data, in order to facilitate performing some kind of transformation on the data

Formulaes-

Here the temperature varies for each species, the first 7 coefficients are used in high temperature range and the next 7 coefficents are used for low temperature range.

Molecular weight is calculated by the following formulae

Molecular weight=(number of atoms)*(atomic weight), where we calculate the molecular weight of all species.

Code explanation:

First we open the ‘thermo.dat’ file to read data and extract information using the fopen command, extraction is done with fgetl command
We call lines from3-5 to eliminate them so that we can call the species block in the file
The reason we did the above step so that we don’t clutter our output with unnecessary data.
We make a for loop so that we can fulfil our objective for all the species, total species present is 53
We use findstr command to find the local temperatue by putting the accurate position of the text from the dat file, similarly for coefficients
Str2num command is used to convert the data into scalar values
Mkdir command is used to make a directory to save the plots for each species in individual folders
For low temp and high temp if loop is used to designate required coefficents for the formula of enthalpy,specific heat.
3 figures are plotted i.e enthalpy vs temp, specific heat vs temp, entropy vs temp. using the plot command
Molecular weight is calculated my comparing the string of elements with their respective weights using the strcmp command.
Molecular mass is weight of all the atoms present in a species.
The name of the species is converted into number by str2num command and subtracting 1 from it we multiply (n-1) to atomic weight because initially we took account of one of the elements of the species.
Cd command is used to change the directory
Save as command is used to save the plots
For loop is ended
Fclose command is used to stop the code from running

code:

clear all
close all
clc

% reading dat file

f2 = fopen('thermo.dat', 'r');
% reading the header information and eliminating it
fgetl(f2) 
fgetl(f2) 
fgetl(f2) 
fgetl(f2) 
fgetl(f2) 

% getting the speicies name and temperature
for i=1:53  
local_temp = fgetl(f2)
species_name = local_temp(1:6)
t = findstr(local_temp, '.')
local_temp(52-3:52+3)
tl = local_temp(t(1)-3:t(1)+3);
tla = str2num(tl);  % converting to scalar
th = local_temp(t(2)-4:t(2)+3);
tha = str2num(th);  % converting to scalar
tm = local_temp(t(3)-4:t(3)+3);
tma = str2num(tm)    % converting to scalar

% getting coefficients
% line 2 of species block
coff1 = fgetl(f2)
A = findstr(coff1, 'E');
coff1(1:12+3)

a1 = coff1(1:A(1)+3);
z1 = str2num(a1);
a2 = coff1(A(1)+4:A(2)+3);
z2 = str2num(a2);
a3 = coff1(A(2)+4:A(3)+3)
z3 = str2num(a3);
a4 = coff1(A(3)+4:A(4)+3);
z4 = str2num(a4);
a5 = coff1(A(4)+4:A(5)+3);
z5 = str2num(a5);

% line 3 of species block
coff2 = fgetl(f2)
A1 = findstr(coff1, 'E');
coff2(1:12+3)

a6 = coff2(1:A1(1)+3);
z6 = str2num(a6);
a7 = coff2(A1(1)+4:A1(2)+3);
z7 = str2num(a7);
a8 = coff2(A1(2)+4:A1(3)+3)
z8 = str2num(a8);
a9 = coff2(A1(3)+4:A1(4)+3);
z9 = str2num(a9);
a10 = coff2(A1(4)+4:A1(5)+3);
z10 = str2num(a10);

% line 4 of species block
coff3 = fgetl(f2)
A2 = findstr(coff1, 'E');
coff3(1:12+3)

a11 = coff3(1:A2(1)+3);
z11 = str2num(a11);
a12 = coff3(A2(1)+4:A2(2)+3);
z12 = str2num(a12);
a13 = coff3(A2(2)+4:A2(3)+3)
z13 = str2num(a13);
a14 = coff3(A2(3)+4:A2(4)+3);
z14 = str2num(a14);

mkdir(['E:\skill lync practices\month 1 matlab\week 1\species\',species_name]);
% calculating enthalpy, entropy and specific heat
t = linspace(tla,tha,100);
R = 8.314

    if t >tma
        cp = (z1+z2.*t+z3.*t.^2+z4.*t.^3+z5.*t.^4).*R;
        h = (z1+(z2.*t)./2+(z3.T^2)./3+(z4.t^3)./4+(z5.t^4)./5+z6./t).*t.*R;
        s = (z1.*log(t)+z2.*t+(z3.*t.^2)./2+(z4.*t.^3)./3+(z5.*t.^4)./4+z6).*R;
    else
        cp = (z8+z9.*t+z10.*t.^2+z11.*t.^3+z12.*t.^4).*R;
        h = (z8+(z9.*t)/2+(z10.*t.^2)/3+(z11.*t.^3)/4+(z12.*t.^4)/5+(z13./t))*R.*t;
        s = (z8.*log(t)+z9.*t+(z10.*t.^2)./2+(z11.*t.^3)./3+(z12.*t.^4)./4+z14).*R;
    end
    
figure (1)
plot(cp,t,'linewidth',3, 'color','b')
xlabel('specific heat');
ylabel('temperature');
title(species_name);

figure (2)
plot(s,t,'linewidth',3,'color','b')
xlabel('enthalpy');
ylabel('temperature');
title(species_name);

figure (3)
plot(h,t,'linewidth',3,'color','b')
xlabel('entropy');
ylabel('temperature');
title(species_name); 

% molecular weight code
elements = ['H', 'C', 'O', 'N', 'A'];
atomic_weight = [1.0079 12.0107 15.999 14.0067 39.948];
mol_mass = 0;
for j=1:length(species_name)
    for k=1:length(atomic_weight)
        if strcmp(species_name(j),elements(k))
            mol_mass=mol_mass+atomic_weight(k);
            save=k;
        end
    end
    n=str2double(species_name(1));
    if n>1
        mol_mass=mol_mass+atomic_weight(k)*(n-1);
    end
    sprintf('molecular weight of %s:%f u',species_name,mol_mass)
end


cd(['E:\skill lync practices\month 1 matlab\week 1\species\',species_name])

saveas(1,'cp vs temp.jpg')
saveas(2,'s vs temp.jpg')
saveas(3,'h vs temp.jpg')
    
end
fclose(f2)

plots of o2, N2, Co2

cp vs temp