Challenge

Project 1 - Parsing NASA thermodynamic data

AAshwani Kumar Singh27 Apr 2022

AIM: - To write a code in matlab to parse nasa thermodynamic data file and then calculate thermodynamic properties of various gas species.

Write a function that extracts the 14 coefficients and calculate the enthalpy, entropy and specific heat 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 species for each species.
Saving the plots as images with appropriate names and dump them in separate folders for each species with suitable name.

File Parsing: -

In general, the term "parsing" means reading an m-file (script or function) and translating it into an internal code that it stores in memory. It is this "parsed" file in memory that is actually run when you execute the code.

`C_p/R=a1+a2T+a3T^2+a4T^3+a5T^4`

`H/(RT)=a1+(a2T)/2+(a3T^2)/3+(a4T^3)/4+(a5T^4)/5+a6/T`

`S/R=a1lnT+a2T+(a3T^2)/2+(a4T^3)/3+(a5T^4)/4+a7`

where: -

T = local temperature

b1 – b2 = high temperature coefficient

b8 – b14 = low temperature coefficient

R = Gas constant = 8.314

PROGRAM: -

Specific Heat

function[C_p] =specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,local_mid_temp,T,R)
if (T>local_mid_temp)
C_p = R*(a1+(a2*T) + (a3*(T.^2))+(a4*(T.^3))+(a5*(T.^4)));
else
    C_p=R*(a8+(a9*T)+(a10*(T.^2))+(a11*(T.^3))+(a12*(T.^4)));
end

Ethalpy

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

Entropy

function [S] = entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,local_mid_temp,T,R)
if (T>local_mid_temp)
    S = R*(a1*log(T)+(a2*T)+(a3*(T.^2)/2)+(a4*(T.^3))+(a5*(T.^4)/4)+a7);
else
    S = R*(a8*log(T)+(a9*T)+(a10*(T.^2)/2)+(a11*(T.^3))+(a12*(T.^4)/4)+a14);
end

Molecular weight

function[M] = molecular_wt(species_name)

atomic_mass = [15.999,1.008,12.011,14.007,39.948];
elements = ['o','H','C','N','A'];

mol_wt = 0;
for i = 1:length(species_name)
    for j = 1:length(elements)
        if strcmp(species_name(i),elements(j))
            mol_wt = mol_wt+atomic_mass(j);
            z=j;
        end
    end

    t = str2double(species_name);
    if (t>1)
        mol_wt = mol_wt + (atomic_mass(z)*(t-1));
    end
end
M = mol_wt;
end

Main code

close all
clear 
clc

f1 = fopen('THERMO.dat','r');
fgetl(f1)
tline2 = fgetl(f1);
% X = temperatures
X = strsplit(tline2,' ');
global_low_temp = str2double(X{2});
global_mid_temp = str2double(X{3});
global_high_temp= str2double(X{4});

for i = 3:5
    A = fgetl(f1);
end

for i = 1:53
    tline6 = fgetl(f1);
    S = strsplit(tline6);
    species_name= S{1};
    A = strfind(tline6,'G');
    temp_value = tline6(A+4:length(tline6));
    B = strsplit(temp_value,' ');
    local_low_temp = str2double(B{1});
    local_mid_temp = str2double(B{2});
    local_high_temp= str2double(B{3});

tline7 = fgetl(f1);
B = strfind(tline7,'E');
a1 = str2double(tline7(1:B(1)+3));
a2 = str2double(tline7(B(1)+4:B(2)+3));
a3 = str2double(tline7(B(2)+4:B(3)+3));
a4 = str2double(tline7(B(3)+4:B(4)+3));
a5 = str2double(tline7(B(4)+4:B(5)+3));

tline8 = fgetl(f1);
C =strfind(tline8,'E');
a6 = str2double(tline8(1:C(1)+3));
a7 = str2double(tline8(C(1)+4:C(2)+3));
a8 = str2double(tline8(C(2)+4:C(3)+3));
a9 = str2double(tline8(C(3)+4:C(4)+3));
a10 = str2double(tline8(C(4)+4:C(5)+3));

tline9 = fgetl(f1);
D = strfind(tline9,'E');
a11 = str2double(tline9(1:D(1)+3));
a12 = str2double(tline9(D(1)+4:D(2)+3));
a13 = str2double(tline9(D(2)+4:D(3)+3));
a14 = str2double(tline9(D(3)+4:D(4)+3));

% R = universal gas constant
R = 8.314;
T = linspace(local_low_temp,local_high_temp,100);
C_p = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,local_mid_temp,T,R);
H = enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,local_mid_temp,T,R);
S = entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,local_mid_temp,T,R);
req_species = ["O2","N2","CO2"];

mkdir(['G:O/',species_name])
C_p(species_name)

figure(1)
plot(T,C_p)
title('Specific heat v/s temperature')
xlabel('Temperature')
ylabel('Specific heat')
image=getframe(gcf);
imwrite(image.cdata,'t vs C_p.png')
saveas(1,'specific heat','jpg')

figure(2)
plot(T,H)
title('Enthalpy v/s Temperature')
xlabel('Temperature')
ylabel('Enthalpy')
image=getframe(gcf);
imwrite(image.cdata,'t vs H.png')
saveas(2,'Enthalpy','jpg')

figure(3)
plot(T,S)
title('Entropy v/s Temperature')
xlabel('Temperature')
ylabel('Entrophy')
image=getframe(gcf);
imwrite(image.cdata,'t vs S.png')
saveas(3,'Entropy','jpg')

[M]= molecular_wt(species_name);
K=sprintf('%s mol_wt=%f',species_name,M);
disp(K)
end

plots for O2: -

specific heat and temperature