Challenge

Project 1 - Parsing NASA thermodynamic data

JJithin P Kumar23 Feb 2022

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. The formulae are shown below.

Here R is the universal gas constant, T is the temperature

PROGRAM TO CALCULATE THE ABOVE GIVEN PARAMETERS:

clear all 
close all
clc

f1= fopen('THERMO.dat');
for i=1:5
fgetl(f1);
end


for i=1:53
    
X=fgetl(f1);
Y= strsplit(X,' '); %splitting the line 
n= length(Y); 
species_name= Y{1}; % invoking the elements
local_low_temp= str2num(Y{n-3});%converting string to number for temperature

local_mid_temp= str2num(Y{n-1});%converting string to number for temperature

local_high_temp= str2num(Y{n-2});%converting string to number for temperature

%extracting the coefficient from the given data
A= fgetl(f1);
a= findstr(A,'E');
a1= A(1:a(1)+3);
a1= str2num(a1);
a2= A(a(1)+4:a(2)+3);
a2= str2num(a2);
a3= A(a(2)+4:a(3)+3);
a3= str2num(a3);
a4= A(a(3)+4:a(4)+3);
a4= str2num(a4);
a5= A(a(4)+4:a(5)+3);
a5= str2num(a5);

B= fgetl(f1);
b= findstr(B,'E');
a6= A(1:b(1)+3);
a6= str2num(a6)
a7= A(b(1)+4:b(2)+3);
a7= str2num(a7);
a8= A(b(2)+4:b(3)+3);
a8= str2num(a8);
a9= A(b(3)+4:b(4)+3);
a9= str2num(a9);
a10= A(b(4)+4:b(5)+3);
a10= str2num(a10);
 
C= fgetl(f1);
c= findstr(C,'E');
a11= A(1:b(1)+3);
a11= str2num(a11);
a12= A(b(1)+4:b(2)+3);
a12= str2num(a12);
a13= A(b(2)+4:b(3)+3);
a13= str2num(a13);
a14= A(b(3)+4:b(4)+3);
a14= str2num(a14);

R= 8.314; %universal gas constant

temp= linspace(local_low_temp,local_high_temp,150);
cp= specific_heat(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,R,temp,local_mid_temp);
H= enthalphy(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,temp,R,local_mid_temp);
S= entrophy(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,temp,R,local_mid_temp);

%invoking the function to calculate molecular weight
M= molecular_trial(species_name);
sprintf('molecular_weight of %s = %d',species_name,M)

mkdir(species_name) % made the directory
cd(species_name)    % entering the created directory

figure(1)
plot(temp,cp,'linewidth',4)
xlabel('TEMPERATURE')
ylabel('SPECIFIC HEAT')
title('TEMPERATURE vs SPECIFICHEAT')
saveas(1,'temp_vs_cp','jpg')  % saving the figures

figure(2)
plot(temp,H,'linewidth',4, 'Color','g')
xlabel('TEMPERATURE')
ylabel('ENTHALPHY')
title('TEMPERATURE vs ENTHALPHY')
saveas(2,'temp_vs_H','jpg')

figure(3)
plot(temp,S,'linewidth',4,'Color','r')
xlabel('TEMPERATURE')
ylabel('ENTROPHY')
title('TEMPERATURE vs ENTROPHY')
saveas(3,'temp_vs_S','jpg')

cd ..  %used for returning back to the main folder
end

fclose(f1)

DETAILS OF FUNCTIONS USED IN THE PROGRAM :

FUNCTION TO CALCULATE SPECIFIC HEAT:

function cp= specific_heat(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,R,temp,local_mid_temp)
if temp < local_mid_temp
cp= (a1+(a2*temp)+(a3*temp.^2)+(a4*temp.^3)+(a5*temp.^4))*R;
else
    cp= (a6+(a7*temp)+(a8*temp.^2)+(a9*temp.^3)+(a10*temp.^4))*R;
end


end

FUNCTION TO CALCULATE ENTROPHY:

function S= entrophy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a13,a14,temp,R,local_mid_temp)
if temp < local_mid_temp
S= (a1*log(temp))+(a2*temp)+(a3*(temp.^2)/2)+(a4*(temp.^2)/2)+(a5*(temp.^2)/2)+a7;
else

S= (a8*log(temp))+(a9*temp)+(a10*(temp.^2)/2)+(a11*(temp.^2)/2)+(a13*(temp.^2)/2)+a14;

end

FUNCTION TO CALCULATE ENTHALPHY:

function H= enthalphy(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,temp,R,local_mid_temp)

if temp < local_mid_temp
H= R*temp.*(a1+(a2*(temp/2)+ (a3*(temp.^2)/3)+ (a4*(temp.^3)/4)+ (a5*(temp.^4)/5)+ (a6./temp)));

else
H= R*temp.*(a7+(a8*(temp/2)+ (a9*(temp.^2)/3)+ (a10*(temp.^3)/4)+ (a11*(temp.^4)/5)+ (a12./temp)));

end

PLOTS:

CO2

CALCULATE MOLECULAR WEIGHT OF EACH SPECIES

function:

function W= molecular_trial(species_name)
atomic_names= ['O','H','N','A','C']; %providing the elements involved in the species

atomic_weights=[16,1,14,40,12]; %providing the corresponding atomic number for each element
W=0;
for i=1:length(species_name)
    for j=1:length(atomic_names)
        if species_name(i)==atomic_names(j)
            W=W+ atomic_weights(j);
            position=j;
        end
    end
    n=str2num(species_name(i));
    if n>=1
        W= W+atomic_weights(position)*(n-1);
    end
end

OUTPUT(from command window)

a6 =

2.5694

ans =

'molecular_weight of O = 16'