Project 1 - Parsing NASA thermodynamic data

AIM

To write a program in matlab to parse the NASA thermodynamic data and file and then calculate the thermodynamic properties of various gas species.

OBJECTIVE

To write a function that extracts the 14 co-efficients and calculates the enthalpy,entropy and specific heats for all species in the data file.

calculating the molecular weight of each species and displaying it in the command window.

plotting cp,enthalpy and entropy for local tempartature range specific for each species.

INTRODUCTION

PARSING DATA :

parsing means to make something understandable .for programming this means to convert information represented in form to another form thats's easier to work with.this is done by partially analusing the data,understanding its underlying structure and then explicity represnting that structure in the code

parsing a file means reading in a data stream of some sort and building an in memory model of the semantic content of the data .this aims at faciltitating perfoming some kind of transformation on the data.

EQUATIONS

The equations that we are going to use in the function to calculate cp,H,S are

where,

cp=specific heat

R=molar gas constant

T=temparature

S=entropy

H=enthalpy

a=co-efficients

FUNCTION CODE FOR SPECIFIC HEAT

function cp = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp)

if (T<=global_midtemp)
    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
end
  

FUNCTION CODE FOR ENTHALPY

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

FUNCTION CODE FOR ENTROPY

function S = entropy_S(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp)
if (T<=global_midtemp)
        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)/5)+a7);

end 
end

FUNCTION CODE FOR MOLECULAR WEIGHT

function mol_weight = weight(species_names)
elements = ['H','C','O','N','A','S'];
atomic_weight = [1 12 16  14 40 32];
species=upper(species_names)

mol_weight=0;
for i=1:length(species)

   for j=i:length(elements)

       if strcmp(species(i),elements(j))
           mol_weight=mol_weight+atomic_weight(j);
           k=j;
       else
           n=str2double(species(i));
           if (n>1)
               mol_weight=mol_weight+atomic_weight(k)*(n-1);
               break
           end 
       end
   end
end
        

MAIN PROGRAM CODE

close all
clear all
clc

% molar gas constant
R = 8.314;

% syntax to open the file 
f1=fopen("THERMO.dat","r")

% TO READ LINES
l1 = fgetl(f1);
l2 = fgetl(f1);
value=strsplit(l2,' ');

%converting string to  number
global_lowtemp = str2num(value{2})
global_midtemp = str2num(value{3})
global_hightemp = str2num(value{4})


%temparature range

% to skip the lines

l3 = fgetl(f1);
l4 = fgetl(f1);
l5 = fgetl(f1);

% reading species,calculating cp,H,S

for i=1:53
    tline = fgetl(f1);
    A = strsplit(tline,' ');
    name_of_species = (A{1});
    low_temp = str2num(A{end-2});
    mid_temp = str2num(A{end-2});
    high_temp = str2num(A{end-1});
T = linspace(low_temp,high_temp,1000);

% finding 14 coefficients
tline1=fgetl(f1);
a=findstr(tline1,'E');

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);

tline2=fgetl(f1);
a=findstr(tline2,'E')

a6=tline2(1:a(1)+3);
a6=str2num(a6);
a7=tline2(a(1)+4:a(2)+3);
a7=str2num(a7);
a8=tline2(a(2)+4:a(3)+3);
a8=str2num(a8);
a9=tline2(a(3)+4:a(4)+3);
a9=str2num(a9);
a10=tline2(a(4)+4:a(5)+3);
a10=str2num(a10);


tline3=fgetl(f1)
a=findstr(tline3,'E');


a11=tline1(1:a(1)+3);
a11=str2num(a11);
a12=tline1(a(1)+4:a(2)+3);
a12=str2num(a12);
a13=tline1(a(2)+4:a(3)+3);
a13=str2num(a13);
a14=tline1(a(3)+4:a(4)+3);
a14=str2num(a14);

% calculating cp,H,S
cp = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,global_midtemp);
H = enthalpy_H(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,global_midtemp);
S = entropy_S(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,global_midtemp);

% calculating mol_weight
mol_weight = weight(name_of_species)
fprintf('molecular weight of %s= %f\n',name_of_species,mol_weight);

% plotting of cp,H,T

% creating a folder
mkdir(name_of_species);
cd(name_of_species);

% plotting T vs cp
figure(1)
plot(T,cp,'linewidth',5,'color',"r")
xlabel('temparature(T)')
ylabel('specificheat(cp)')
grid on
title(name_of_species)
saveas(figure(1),'specific_heat.jpg');

%plotting T vs H
figure(2)
plot(T,H,'LineWidth',5,'color','b')
xlabel('temparature(T)')
ylabel('ENTHALPY_H')
grid on
title(name_of_species)
saveas(figure(2),'ENTHALPY_H.jpg');

%plotting T vs S
figure(3)
plot(T,S,'LineWidth',5,'color','g')
xlabel('temparature(T)')
ylabel('ENTROPY_S')
grid on
title(name_of_species)
saveas(figure(3),'ENTROPY_S.jpg');
cd ..

end

CODE EXPLANATION

Initially the value of 'R' is being defined.

Then we use fopen command to open the file 'THERMO.dat'.

Further we use the 'fgetl' to start reading the lines and after reading the first two lines, from the second line converting the strings to numbers using str2num command and assigning global (low,mid and high) temperatures.

Then we have written a command to get the temperature range for calculation and plotting purpose.

Then again using the fgetl command to go to thel next 3 lines and skipping it.

Then we use a for loop to get 53 species and their temperatures (low, mid, high) and the 14 coefficients.

In the for loop we again use the fgetl command and then the next line is read and from that line the species name, the three local temperatures are read and stored.

Then we use fgetl command to go to further line and get the first 7 coefficients and store them. Similarly using the fgetl command we move to the next two lines and get the remaining coefficients.

Then after getting the 14 coefficients, we use these coefficients and by calling the functions we calculate cp,H,S.

Further we use the Molecular weight for that species.

Further we have used a command to change the directory so that I can save the files at a particular lo

cation.After changing the directory I have used 'mkdir' to create a new folder with the name of the current species and then a 'cd' command to make mkdir as the current directory.

Then further we use plot command to plot temperature vs (cp,enthalpy,entropy).

In this plotting we use the figure command to get the three different plots and saveas command to save the figures in the folder

we used the cd .. command to close the folder

Then again we change our directory to again start the loop.

So the loop continues to function till we get all the 53 species and then gets terminated.

end command is used at last to end the loop.

OUTPUTS/GRAPHS FOR O2

PLOTS FOR N2

PLOTS FOR CO2

SCREENSHOT OF FOLDER

MOLECULAR WEIGHT OF SPECIES

CONCLUSION

So here we are able to read the data from the file that is THERMO.dat.

Then using this data we are able to calclulate the thermodynamic proporties such as specific heat ,entropy,entolpy and molecular weight and also plotted for these proporties with respect to temparature.