Challenge

Project 1 - Parsing NASA thermodynamic data

GGuberan V24 May 2023

Aim

1. 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

before writing the program we have to download the thermodynamic file from the given datafile and after that we have to find the cp,h,S for the proogram which created and finally the molecular weights of the atoms in the file

and we have to understand the specific heat, Enthalpy,entropy and molecular weight of the atoms

Molecular weight

The sum of the atomic masses of all atoms in a molecule, based on a scale in which the atomic masses of hydrogen, carbon, nitrogen, and oxygen are 1, 12, 14, and 16

Program for the file

f1 = fopen('THERMO.dat','r');

fgetl(f1);

temp = str2num(fgetl(f1));

%Global temparture

g_low = temp(1);

g_mid = temp(2);

g_high= temp(3);

for i = 1:3

fgetl(f1);

end

for j = 1:53

line = fgetl(f1);

A = strsplit(line,' ');

% to identify species

species =(A{1});

% Local_temparture

low_t = str2num(A{end-3});

high_t = str2num(A{end-2});

mid_t = str2num(A{end-1});

%co-efficients of A_line between A1 - A5

a_line = fgetl(f1);

a = findstr(a_line,'E');

% converting the strings to number

a1 = a_line(1:a(1)+3);

a1 = str2num(a1);

a2 = a_line(a(1)+4:a(2)+3);

a2 = str2num(a2);

a3 = a_line(a(2)+4:a(3)+3);

a3 = str2num(a3);

a4 = a_line(a(3)+4:a(4)+3);

a4 = str2num(a4);

a5 = a_line(a(4)+4:a(5)+3);

a5 = str2num(a5);

% Coefficients of B_line between B1 - B5

b_line = fgetl(f1);

b = findstr(b_line,'E');

%converting the Strings to number

b1 = b_line(1:b(1)+3);

b1 = str2num(b1);

b2 = b_line(b(1)+4:b(2)+3);

b2 = str2num(b2);

b3 = b_line(b(2)+4:b(3)+3);

b3 = str2num(b3);

b4 = b_line(b(3)+4:b(4)+3);

b4 = str2num(b4);

b5 = b_line(b(4)+4:b(5)+3);

b5 = str2num(b5);

% Coefficient of C_line between C11 - C14

c_line = fgetl(f1);

c = findstr(c_line,'E');

%converting the Strings to Number

c1 = c_line(1:c(1)+3);

c1 = str2num(c1);

c2 = c_line(c(1)+4:c(2)+3);

c2 = str2num(c2);

c3 = c_line(c(2)+4:c(3)+3);

c3 = str2num(c3);

c4 = c_line(c(3)+4:c(4)+3);

c4 = str2num(c4);

% Calculating the specific heat, enthalpy, entropy @ High temparture

R = 8.3145;

T_H = linspace(low_t,mid_t,100);

cp = (a1+(a2.*T_H)+(a3.*T_H.^2)+(a4.*T_H.^3)+(a5.*T_H.^4))*R;

H = (a1+(a2.*T_H/2)+(a3.*(T_H.^2)/3)+(a4.*(T_H.^3)/4)+(a5.*(T_H.^4)/5)+b1.*T_H)*R;

S = (a1*log(T_H)+(a2.*T_H)+(a3.*(T_H.^2)/2)+(a4.*(T_H.^3)/3)+(a5.*(T_H.^4)/4)+b2)*R;

% Calculating the specific heat, enthalpy, entropy @ Low temparture

T_L = linspace(mid_t,high_t,100);

cp1 = (b3+(b4.*T_L)+(b5.*T_L.^2)+(c1.*T_L.^3)+(c2.*T_L.^4))*R;

H1 = (b3+(b4.*T_L/2)+(b5.*(T_L.^2)/3)+(c1.*(T_L.^3)/4)+(c2.*(T_L.^4)/5)+c3.*T_L)*R;

S1 = (b3*log(T_L)+(b4.*T_L)+(b5.*(T_L.^2)/2)+(c1.*(T_L.^3)/3)+(c2.*(T_L.^4)/4)+c4)*R;

% To create a folder

str = sprintf('E:\\Project_1_nasa\\Nasa_therm_data\\%s',species);

mkdir(str);

cd(str);

% ploting the figures of specific heat,Enthalpy,entropy

figure(1)

plot(T_H,cp,'color','K')

hold on

plot(T_L,cp1,'color','r')

hold off

xlabel('Temparature')

ylabel('Specific heat')

legend('High temparture','low Temparature')

saveas (gcf,'Specific heat')

figure(2)

plot(T_H,H,'color','c')

hold on

plot(T_L,H1,'Color','g')

hold off

xlabel('Temparature')

ylabel('Enthalpy')

legend('High temparture','low Temparature')

saveas(gcf,'Enthalpy')

figure(3)

plot(T_H,S,'Color','b')

hold on

plot(T_L,S1,'Color','r')

hold off

xlabel('Temparature')

ylabel('Entropy')

legend('High temparture','low Temparature')

saveas(gcf,'Entropy')

cd ..

%To calculate Molecular weight

elements = ['H','C','N','O','AR','(S)'];

Atomic_weight = [1,12,14,16,40,0,0,0,0];

molecular_wt = 0;

for k = 1:length(species);

[num,status] = str2num(species(k));

if status == 0;

Tt = find(elements == species(k));

molecular_wt(k) = Atomic_weight(Tt);

else

molecular_wt(k-1) = num*molecular_wt(k-1);

end

t_M=sum(molecular_wt);

K = sprintf('Molecular weight of %s is %f',species,t_M);

disp(K)

end

Explanation

By this program we are able to get the output values of specific het,enthalpy, entropy and molecular weights for the nasa thermodynamic data

Commands used to get the code in the data file

Fgetl

Fopen

First with the use of fopen command we can able to open the thermo.data file and after that with the use of Fgetl command we can able to get the lines we want to load the variable from the file

By using fgetl command we can skip the first three lines of the file because the lines are header file which not needed after that we can load the temperature strings of Global_temp = '300 1000 5000'

with these strings we can find the low,mid,and high temperatures and convert the strings to the number using str2num command

afterthat we can identify the coefficients of a,b,c seperately using the method which used to convert the string to number in temperature convertion for the first line of the three coeffiecients are taken with1:a,b,c because it was a starting variable of the line after that for a2,b2,andc2 we can use the string of a1 due to were a2 starts from the ending of the a1 like that we can find those 14 coefficents

To find the Cp,S,H outputs

with this formula which is given to identify the cp,S,H for the data file with the high_temperature and low_temperature using linspace commands

after finding the outputs for the cp,h,and s we can now plot the figures of Enthalpy,Entrophy and Specific heat with the first seven coefficients as high temperature and second seven coefficient are low temperature and then with the mdir command we can able to create the directory which we need to save the figures in a same directory

After that to find the molecular weight of the species with the same str2num command and then we can run the program to get the needed output plots and molecular weights of the species

Errors faced while programing

While programing the data for cp,s,and h gets the error of arrays are not compitable in sizes and resolved it by rearranging the temperature function

while creating molecular weight gets Undefined function 'find' for input arguments of type 'string' used "=', instead of ' = ='

Screenshots of output

Function file for finding coefficients and main program to identify molecular weight are attached

plots for N2