Challenge

Project 1 - Parsing NASA thermodynamic data

DDhananjaya T5 Jul 2022

Main Program:

clear all
close all
clc

% TO open the thermal data file
f1=fopen('THERMO.dat','r');

% get heading file
heading=fgetl(f1);


% Global Temperature Values
global_temp=fgetl(f1);
x=strsplit(global_temp);

global_low_temp=str2double(x{2}); 
global_mid_temp=str2double(x{3});
global_high_temp=str2double(x{4});
fgetl(f1)
fgetl(f1)
fgetl(f1)

% getting Local temperature information of individual species.
for i=1:53 % Running for a loop for every molecule
line1=fgetl(f1); % assigning the molecular data's 1st line from the file to species
species_name=line1(1:6); % assigning the species name from the 1st 6 elements of species array.

% Local temperature
local_temp1=line1(49:55);
low_temp=str2double(local_temp1);

local_temp2=line1(58:65)
mid_temp=str2double(local_temp2);

local_temp3=line1(68:75)
high_temp=str2double(local_temp3);

% To extract the coefficient values

line2=fgetl(f1);
line3=fgetl(f1);
line4=fgetl(f1);

a=strfind(line2,'E');
b=strfind(line3,'E');
c=strfind(line4,'E');

% Extracting the coefficient of high temperature.
a1=str2double(line2(1:a(1)+3));
a2=str2double(line2(a(1)+4:a(2)+3));
a3=str2double(line2(a(2)+4:a(3)+3));
a4=str2double(line2(a(3)+4:a(4)+3));
a5=str2double(line2(a(4)+4:a(5)+3));
a6=str2double(line3(1:b(1)+3));
a7=str2double(line3(b(1)+4:b(2)+3));

% Extracting the coefficient of Low temperature.
a8=str2double(line3(b(2)+4:b(3)+3));
a9=str2double(line3(b(3)+4:b(4)+3));
a10=str2double(line3(b(4)+4:b(5)+3));
a11=str2double(line4(1:c(1)+3));
a12=str2double(line4(c(1)+4:c(2)+3));
a13=str2double(line4(c(2)+4:c(3)+3));
a14=str2double(line4(c(3)+4:c(4)+3));

% Universal gas constant
R=8.314;
t=linspace(low_temp,high_temp,500);

% Calculating Specific heat
c_p=specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,mid_temp,R,t);

% calculating enthalpy
H=enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,R,t,mid_temp);

% calculating entropy
S=entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,R,t,mid_temp);

% Creating folder
data=strcat('properties of .....',species_name);
mkdir(data);
file=pwd;

%plotting
figure(1)
plot(t,c_p,'linewidth',3,'color','g')
data1=strcat(species_name,'temperature vs specific heat');
xlabel('Temperature')
ylabel('Specific heat')
title(species_name)
f=fullfile(data)
cd(f);
saveas(1,[pwd '/Specific heat vs temperature.png'])
cd(file)

figure(2)
plot(t,H,'linewidth',3,'color','c')
data1=strcat(species_name,'temperature vs enthaloy');
xlabel('Temperature')
ylabel('Enthalpy')
title(species_name)
cd(f);
saveas(2,[pwd '/Enthalpy vs temperature.png'])
cd(file)

figure(3)
plot(t,S,'linewidth',3,'color','b')
data1=strcat(species_name,'temperature vs entropy');
xlabel('Temperature')
ylabel('Entropy')
title(species_name)
cd(f);
saveas(3, [pwd '/Entropy vs temperature.png'])
cd(file)

molecular_weight_calc=molecular_weight(species_name);
k=sprintf('%s mol_wt = %f',species_name,molecular_weight_calc);
disp(k)
end
fclose(f1)

Functional Program 1: Calculating thermodynamic Properties(Specific heat,enthalpy,entropy)

function c_p = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,mid_temp,R,t)
if t<=mid_temp
    c_p=(a8+a9.*t+a10.*t.^2+a11.*t.^3+a12.*t.^4).*R;
else
    c_p=(a1+a2.*t+a3.*t.^2+a4.*t.^3+a5.*t.^4).*R;
end

function H = enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,R,t,mid_temp)

if t<=mid_temp
    H=(a8+(a9.*t./2)+(a10.*t.^2/3)+(a11.*t.^3/4)+(a12.*t.^4/5)+(a13./t)).*R.*t;
else
    H=(a1+(a2.*t/2)+(a3.*t.^2/3)+(a4.*t.^3/4)+(a5.*t.^4/5)+(a6./t)).*R.*t;
end

function S = entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,R,t,mid_temp)

if t<=mid_temp
    S=(a8*log(t)+a9.*t+(a10.*t.^2/2)+(a11.*t.^3/3)+(a12.*t.^4/4)+a14).*R;
else
    S=(a1*log(t)+a2.*t+(a3.*t^2/2)+(a4.*t.^3/3)+(a5.*t.^4/4)+a7).*R;
end

Functional Program 2: Calculating the molecular weight of species mentioned in data file.

function molecular_weight_calc=molecular_weight(species_name)
elements=['O','H','C','N','A'];
atomic_mass=[15.999,1.008,12.011,14.007,39.948];
mol_wt=0;
for i=1:length(species_name)
    for j=1:length(elements)
        if strcmpi(species_name(i),elements(j))
            mol_wt=mol_wt+atomic_mass(j);
            z=j;
        end
    end
    t=str2num(species_name(i));
    if(t>1)
        mol_wt=mol_wt+(atomic_mass(z)*(t-1));
    end
    molecular_weight_calc=mol_wt
end

Commands Used:

fopen- 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 into numbers.

strfind-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.

CODE EXPLANATION:

Opening and reading the given data from the folder using fopen command.
fgetl is used to read the file and skip the file.
the global temperature data can be stored in after header.
strsplit comand is used to get the string splitted.
giving max,med and min ranges to the temperature by finding it in data.
inorder to obtain the first objective of finding the co-efficients(a1-a14)
a loop is created for 1:53, because we are having 53 species in the data .
obtain the header by extracting the first line.
the global temp ranges are extracted by using str2double command.
all species names and temp ranges are available in the header line.
linspace command is used to obtain an array of local_min_temp to the local_max_temp.
the corresponding equations to find cp,H and S is put inside a loop along with if else statement according to the temp greater or lessthan local medium temp.
the high temp and low temp coefficients are obtained ,thus the cp,H and S can be finded easily.
plotting the cp v/s temp, H v/s temp and S v/s temp using plot command
the corresponding x and y labels, titles and figure number is given in each case
this will take part inside the previous loop and thus the curve will ploted for each 53 species.
saveas command is used to save the curve as images.
folder is created using mkdir command
and thus the 3 plot for each 53 species areobtained and saves in the corresponding species folder.