Project 1 - Parsing NASA thermodynamic data

AIM:

To write a program in MATLAB/OCTAVE to parse the thermodynamic data file and then calculate the thermodynamic properties of various gaseous species.

EQUATION/FORMULA USED:

write a function that extracts the 14 coefficients and calculates the enthalpy, entropy, and specific heats for all the species in the 'THERMO.dat' file. The formulae are shown below.

`(Cp)/R = a1 + a2.T + a3.T^2 + a4.T^3 + a5.T^4`

`(H)/(RT) = a1 + a2.T/2 + a3.T^2/3 + a4.T^3/4 + a5.T^4/5 + a6. 1/T`

`(S)/(R) = a1 lnT + a2.T + a3.T^2/2 + a4.T^3/3 + a5.T^4/4 + a7`

Here R is the universal gas constant, T is the temeprature.

OBJECTIVE:

1. To write a function that extracts the 14 coefficients
2. To calculate the enthalpy, entropy and specific heats for all the species in the data file.
3. To calculate the molecular weight of each species and display it in the command window.
4. To plot the Cp, Enthalpy and Entropy for the local temperature range (low temperature: high temperature) specific for each species.

THEORY:

Data parsing is a method where one string of data gets converted into a different type of data. When we receive your data in raw HTML, a parser will take the said HTML and transform it into a more readable data format that can be easily read and understood.

Parsing a file means reading in a data stream of some sort and building an in-memory model of the semantic content of that data. This aims at facilitating performing some kind of transformation on the data.

BODY:

1. CODE:

MAIN CODE:

clear all
close all
clc

f = fopen('THERMO.dat','r');          %opening the file for reading purpose;here, f is the pointer to the file.

%skipping the unwanted lines i.e. the first five lines are not required
fgetl(f);
fgetl(f);
fgetl(f);
fgetl(f);
fgetl(f);

%molecular weight for different species
m = [16 32 1 2 17 18 33 34 12 13 14 14 15 16 28 44 29 30 31 31 32 25 26 27 28 29 30 42 41 42 28 27 31 14 29 44 15 16 17 30 44 43 43 43 42 26 41 28 40 44 43 44 43 ] ;

%making of required plots for each of 53 species
for i=1:53
    plotmaker(f,m,i)                      %calling the user-defined function plotmaker()
end

Function Code:

function [a] = plotmaker(f,m,i)

line1 = fgetl(f);                                     %extracting the first line out of four for a particular species
spline1 = strsplit(line1,' ');                        %splitting the above extracted line using strplit(); here, ' ' is the delimitter
species=spline1{1};                                   %storing the name of the specie ; here {} is necessary because spline is a cell array
localtemplow=str2double(spline1{6});                  %storing the local low temperature for a particular specie
localtemphigh=str2double(spline1{7});                 %storing the local high temperature for a particular specie
localtempmid=str2double(spline1{8});                  %storing the local medium temperature for a particular specie

% generating the values of temperature  
lowtemp = linspace(localtemplow,localtempmid,100);    
hightemp=linspace(localtempmid,localtemphigh,100);

%displaying the molecular weight of the specie
fprintf('molecular weight of %s is = %f u \n',species,m(i))

c=1;

for i=1:3
tline=fgetl(f);                                       %extracting the next line out of four for a particular specie
E=strfind(tline,'E');                                 %finding the position of E in the above extracted line
for j=1:length(E)
    coeff(c)=str2double(tline(E(j)-11:E(j)+3));       %extracting the coefficients of data type double
    c=c+1;
end
end

R=8.314;                                              % universal gas constant

%finding Cp,H and S values for different values of lowtemp  
for i=1:100
    lowcp(i)=R*(coeff(8)+coeff(9)*lowtemp(i)+coeff(10)*lowtemp(i)^2+coeff(11)*lowtemp(i)^3+coeff(12)*lowtemp(i)^4);
    lowh(i)=R*lowtemp(i)*(coeff(8) + coeff(9)*lowtemp(i)/2 + coeff(10)*(lowtemp(i)^2)/3 + coeff(11)*(lowtemp(i)^3)/4+coeff(12)*(lowtemp(i)^4)/5+coeff(13)/lowtemp(i));
    lows(i)=R*(coeff(8)*log(lowtemp(i))+coeff(9)*lowtemp(i)+coeff(10)*(lowtemp(i)^2)/2+coeff(11)*(lowtemp(i)^3)/3+coeff(12)*(lowtemp(i)^4)/4+coeff(14));
end

%finding Cp,H and S values for different values of hightemp
for i=1:100
    highcp(i)=R*(coeff(1)+coeff(2)*hightemp(i)+coeff(3)*hightemp(i)^2+coeff(4)*hightemp(i)^3+coeff(5)*hightemp(i)^4);
    highh(i)=R*hightemp(i)*(coeff(1) + coeff(2)*hightemp(i)/2 + coeff(3)*(hightemp(i)^2)/3 + coeff(4)*(hightemp(i)^3)/4+coeff(5)*(hightemp(i)^4)/5+coeff(6)/hightemp(i));
    highs(i)=R*(coeff(1)*log(hightemp(i))+coeff(2)*hightemp(i)+coeff(3)*(hightemp(i)^2)/2+coeff(4)*(hightemp(i)^3)/3+coeff(5)*(hightemp(i)^4)/4+coeff(7));
end

%making folder for saving the plots
nasagraphs = species;
mkdir(nasagraphs);
current=pwd;
cd(nasagraphs);

%plotting of Cp vs temperature
figure (1)
plot(lowtemp,lowcp,'linewidth',3,'color','b')
hold on 
plot(hightemp,highcp,'linewidth',3,'color','r')
hold off
ylabel('Cp');
xlabel('Temperture');
legend('Low temperature','High temperature');
title(['Specific heat vs temperature ',species]);
fig= sprintf('specific heat of %s.png',species);         %name of the image of the plot 
saveas(gca,fig);                                         %saving the image 

%plotting of H vs Temperature
figure (2)
plot(lowtemp,lowh,'linewidth',3,'color','b')
hold on 
plot(hightemp,highh,'linewidth',3,'color','r')
hold off
ylabel('H');
xlabel('Temperture');
legend('Low temperature','High temperature');
title(['Enthalpy vs temperature ',species]);
fig= sprintf('enthalpy of %s.png',species);               %name of the image of the plot 
saveas(gca,fig);                                          %saving the image

%plotting of S vs Temperature
figure (3)
plot(lowtemp,lows,'linewidth',3,'color','b')
hold on 
plot(hightemp,highs,'linewidth',3,'color','r')
hold off
ylabel('S');
xlabel('Temperture');
legend('Low temperature','High temperature');
title(['Entropy vs temperature ',species]);
fig= sprintf('entropy of %s.png',species);                 %name of the image of the plot 
saveas(gca,fig);                                           %saving the image
cd(current)

end

1. STEP-WISE EXPLANATION OF THE CODE:

• This program is written and executed using octave.
• Starting with all the general command e. clear all, close all & clc.
• Inputting all the code comment at all the required location starting with %.
• Put the THERMO.dat file in the same directory where the octave program is saved.
• Then we will write the main code.
• We will take the pointer f and make it read all the data in the THERMO.dat file, r stands for read-only.
• Skipping the first 5 lines, using fgetl() command will result to move to the next lines.
• Then the code for the molecular weight is written.
• Then the further code is written in a loop so that the things get repeated 53 times again and again.
• Then function code is written named plotmaker.
• Starting with a function code followed by fgetl(), then strsplit command.
• Then the local temperature is stored using the str2double() command.
• Then we will write code to find out the entropy, specific heat and enthalpy and their condition to exist.
• Then writing the code to display the molecular weight of the species.
• Then we save the plot using the mkdir() and the cd() commands.
• Then the code is executed and the plot of Cp v/s T, H v/s T and S v/s T graphs of all the species are generated.
• Finally, we use the end command to end the code.

3. ERROR FACED WHILE PROGRAMMING:

No major error during the execution of code.

OUTPUTS:

folder saved:

PLOT FOR O2:

PLOT FOR N2:

PLOT FOR CO2:

MOLECULAR WEIGHT:

RESULT:

Hence, we have successfully done all the calculation and also successfully plotted the graph.