Project 1 - Parsing NASA thermodynamic data
REPORT
AIM-Write a program to parse NASA thermodynamic data file and then calculate thermodynamic properties for various species
OBJECTIVE:-
> Write a function that extracts the 14 co-efficients and calculates the enthalpy, entropy and specific heats for all the species in the data file
> Calculate the molecular weight of each species and display it in the command window.
> Plot the Cp, Enthalpy and Entropy for the local temperature range (low temperature : high temperature) specific for each species.
> Save the plots as images with appropriate names and dump them in separate folders for each species with suitable name.
> Attach screenshot of the window where all the folders are saved and Plots for o2, N2 and Co2 species
FILE PARSING
Parsing a file means reading in a data stream and building a memory model of the content of that data. This aims at facilitating perfoming some kind of transformation on the data. Parsing splits a file or other input into pieces of data that can be easily stored or manipulated
dat file is a data file containing 14 coefficients for 53 different elements given by NASA. These coefficients are utilized to calculate the specific heat, enthalpy & entropy for a particular species. Each element has its own range of local temperature and coefficients
Where,
R-Universal gas constant
T-Temperature in K
Cp-Specific heat in kj
S-Entropy in kj/mol-k
H-Enthalpy in kj/mol
a(i)=coefficients , where i=1 to 14
SPECIFIC HEAT -Cp
Specific heat is the quantity of heat required to raise the temperature of one fram of a substance by one degre celsius.The relationship between heat and temperature change expressed in the form shown below
Cp=R*(a1+(a2*T)+(a3*(T).^2)+(a4*(T).^3)+(a5*(T).^4))
ENTROPY-S
Entropy is the measure of system's thermal energy per unit temperature that is unavailable for usefull work Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system.Equation for entropy is shown below
S=R*(a1.*log(T)+(a2*T)+((a3*(T).^2)/2)+((a4*(T).^3)/3)+((a5*(T).^4)/4)+a7)
ENTHALPY-H
Enthalpyis a property of thermodynamic system and it is the sum of the internal energy and the product of the pressure and volume of a thermodynamic system.Equation for enthalphy is shown below
H=R*T.*(a1+((a2*T)/2)+((a3*(T).^2)/3)+((a4*(T).^3)/4)+((a5*(T).^4)/5)+((a6./T))
Main program
close all
clear all
clc
% Reading the data file
% open file and reading THERMO.dat file
f1=fopen('THERMO.dat','r');
get=fgetl(f1);
% Now reading global temperature from this file
temp=fgetl(f1);
% Spliting
s=strsplit(temp);
% Converting string cells into numbers
templow=str2num(s{2});
tempmid=str2num(s{3});
temphigh=str2num(s{4});
% Universal gas constant R
R=8.134;
% Skipping command lines by using for loop
for i=1:3
get=fgetl(f1);
end
% Reading local temprature and coefficients for each species
for j=1:53
tline=fgetl(f1);
%Spliting into cell array
A=strsplit(tline,' ');
% Reading the name of species
species=A{1};
% Reading local temperature for each species
low_temp=str2num(A{end-3}); %Converting string into number
med_temp=str2num(A{end-2});
high_temp=str2num(A{end-1});
T=linspace(low_temp, high_temp, 1000);
% Getting the next line
tline1=fgetl(f1);
% To find the string E
a=strfind(tline1,'E');
% Finding 7 higher coefficients and 7 lower coefficients
a1=tline1(1:a(1)+3);
a1=str2num(a1);
a2=tline1(a(1)+4:a(2)+3);
a2=str2num(a2);
a3=tline1(a(2)+4:a(3)+3);
a3=str2num(a3);
a4=tline1(a(3)+4:a(4)+3);
a4=str2num(a4);
a5=tline1(a(4)+4:a(5)+3);
a5=str2num(a5);
% getting the next line
tline2=fgetl(f1);
% to find string E
b=strfind(tline2,'E');
a6=tline2(1:b(1)+3);
a6=str2num(a6);
a7=tline2(b(1)+4:b(2)+3);
a7=str2num(a7);
a8=tline2(b(2)+4:b(3)+3);
a8=str2num(a8);
a9=tline2(b(3)+4:b(4)+3);
a9=str2num(a9);
a10=tline2(b(4)+4:b(5)+3);
a10=str2num(a10);
% getting the next line
tline3=fgetl(f1);
d=strfind(tline3,'E');
a11=tline3(1:d(1)+3);
a11=str2num(a11);
a12=tline3(d(1)+4:d(2)+3);
a12=str2num(a12);
a13=tline3(d(2)+4:d(3)+3);
a13=str2num(a13);
a14=tline3(d(3)+4:d(4)+3);
a14=str2num(a14);
% calculating specific heat
Cp=specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid);
% calculating entropy
S= entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid);
% calculating enthalpy
H=enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,a14,T,R,tempmid);
% calculating molecular weight
W=molecular_weight(species);
mkdir(species)
cd(species)
%ploting
%plot 1 Specific heat vs Temperature
figure(1)
plot(T,Cp,'LineWidth',2,'Color','r');
xlabel('TEMPERATURE(K)');
ylabel('SPECIFIC HEAT(KJ');
title(sprintf('Specific heat vs Temperature range of %s',species))
saveas(figure(1),'cp.jpg')
% plot-2 Entropy vs Temperature
figure(2)
plot(T,S,'linewidth',2,'color','b')
xlabel('TEMPERATURE(K)')
ylabel('ENTROPY(KJ/MOL-K)')
title(sprintf('Entropy vs Temperature range of %s',species))
saveas(figure(2),'s.jpg')
%plot-3 Enthalpy vs Temperature
figure(3)
plot(T,H,'LineWidth',2,'Color','r');
xlabel('TEMPERATURE(K)');
ylabel('ENTHALPY(KJ/MOL)')
title(sprintf('Enthalpy vs Temperature range of %s',species))
saveas(figure(3),'h.jpg')
cd ..
end
STEPS
>First we open open THERMO.dat file and reading this file using fopen command
>Then we read the first line using fgetl command and we read the temperatures and we split temperature using strsplit to convert into cell array
>Then we will convert this string to numbers using str2num command to find low , mid and high temperatures
>Then we will creat an array for temperature between low and hihg temperatures using linspace command
> We skip the command lines by using fgetl command in loop
>Now using fgetl command in loop to read 53 species or elements in the file
>Then we split into cell array to find species line and then find species name and the find the number of temperatures in species lines
>Then we read the new line using fegtl
>We have to extract the values of coefficients ,for this we have to find position of E
>To find string E we use strfind command
>Taking position of E as reference we find the values of coefficients from the lines for each species
>First seven coefficients are for higher temperature and then remaining seven coefficients are for lower temperature
>We created functions for specific heat, entropy, enthalpy and molecular weight and using this functions we can find the values
>Now by using cd we are changing the folder and by using mkdir to creat new folder
>Then we are ploting the plots for all species and saving the plots by using saveas command
function Cp=specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid)
% calculating specific heat for higher anf lower temperature
if (T<=tempmid)
Cp=R*(a8+(a9.*T)+(a10.*(T).^2)+(a11.*(T).^3)+(a12.*(T).^4));
else
Cp=R*(a1+(a2.*T)+(a3.*(T).^2)+(a4.*(T).^3)+(a5.*(T).^4));
end
endfunction S= entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid)
if (T<=tempmid)
S=R.*(a8.*log(T)+(a9*T)+((a10*(T).^2)/2))+((a11*(T).^3)/3)+((a12*(T).^4)/4)+a14;
else
S=R.*(a1.*log(T)+(a2*T)+((a3*(T).^2)/2))+((a4*(T).^3)/3)+((a5*(T).^4)/4)+a7;
end
endfunction H=enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,a14,T,R,tempmid)
if T<=(tempmid)
H=R*T.*(a8+((a9*T)/2)+((a10*(T).^2)/3)+((a11*(T).^3)/4)+((a12*(T).^4)/5)+((a13./T)));
else
H=R*T.*(a1+((a2*T)/2)+((a3*(T).^2)/3)+((a4*(T).^3)/4)+((a5*(T).^4)/5)+((a6./T)));
end
endfunction W=molecular_weight(species)
% Defining atomic name of the species
atomic_name=['H','C','N','O','Ar'];
% Defining atomic weight
atomic_weight=[1.008 12.01 15.99 14.007 39.48];
% Molecular weight starting fr0om zero
W=0;
for i=1:length(species) % loop runs up to the length of species
for j=1:length(atomic_name) % loop runs up to the length of atomic name
if strcmp(species(i),atomic_name(j))% comparing the two strings
W=W+atomic_weight(j);
position=j;
end
end
n=str2double(species(i)); % here we were searching for more atoms if any ,we are adding the weight of that atom
if n>1
W=W+atomic_weight(position)*(n-1);
end
fprintf('Molecular weight of %s = %f \n',species,W)
end