Project 1 - Parsing NASA thermodynamic data

Aim:- To write a code in Matlab to parse the NASA thermodynamics data file and then calculate the thermodynamic properties of various gas species.

Objective:- 

1. To write a function that extracts the 14 coefficients and calculates the enthalpy,entropy, and specific heats for all the species in the NASA thermodynamic data file ''Thermo.dat''.

The NASA polynomials have the form as shown below:

   Cp/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 R is the universal gas constant , T is the temperature

2. To calculate the molecular weight of each species and display it in the command window.

3. To plot the Cp, Enthalpy, and Entropy for the local temperature range(low temperature: high temperature)        species for each species.

4. To save the plots as images with appropriate names and dump them in separate folders for each species            with suitable  name automatically.

File Parsing:-

File parsing refers to how information can be read from a particular text file or any type of file and how that information can be used in a computer program.

Step 1- Define the function

Step 2 - create an input parser object.

Step 3 - add inputs to the scheme. 

Step 4- set properties to adjust parsing.

Step 5 - parse the inputs 

Step 6- use the inputs in function.

step 7 - calling function.

NASA Thermodynamic File

THERMO.dat file is a data file containing 14 coefficients for 53 different elements given by NASA . These coefficients are utilized to calculate the specific heat , enthalpy & entropy for a particular element. Each element has its own range of local temperature. 

Coding Functions:-

1. Specific Heat:-

   Cp = (a1+a2T +a3T^2+a4T^3+a5T^4)*R

function Cp = specificheat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,Temp,R,global_medium_temp)
%comparing with global temperature
%if less than global temperature - minimum coefficients are taken
if Temp <=global_medium_temp

Cp = R*(a8+(a9*Temp)+(a10*(Temp).^2)+(a11*(Temp).^3)+(a12*(Temp).^4));
else
Cp=R*(a1+(a2*Temp)+(a3*(Temp).^2)+(a4*(Temp).^3)+(a5*(Temp).^4));
% Else maximum coefficients are taken
end
end

2. Entropy:-

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

function S= Entropy_calc(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,Temp,R,global_medium_temp)

%comparing with global temperature
%if less than global temperature-minimum coefficients are taken

if Temp <= global_medium_temp
S=R.*(A8.*log(Temp)+(a9.*Temp)+(a10*((Temp).^2)/2)+(a11*((Temp).^3)/3)+(a12*((Temp).^4)/4)+a14);
else

%Else - maximum coefficients are taken
S= R.*(a1.*log(Temp)+(a2.*Temp)+(a3*((Temp).^2)/2)+(a4*((Temp).^3)/3)+(a5*((Temp).^4)/4)+a7);
end
end

3. Enthalpy:-

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

function H=Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,Temp,R,global_medium_temp)

%comparing with global temperature
%if less than global temperature-minimum coefficients are taken

if Temp<= global_medium_temp
H=R*Temp.*(a8+((a9*Temp)/2)+((a10*(Temp).^2)/3)+((a11*(Temp).^3)/4)+((a12*(Temp).^4)/5)+((a13./Temp)));
else
%Else maximum coefficients are taken

H=R*Temp.*(a1+((a2*Temp)/2)+((a3*(Temp).^2)/3)+((a4*(Temp).^3)/4)+((a5*(Temp).^4)/5)+((a6./Temp)));
end
end

4. Molecular Weight:-

function Molecularweight=Molecular_weight(Species_SP)
%Standard-Atomic name
atomic_name=['H','C','O','N','A'];
%Hydrogen,Carbon,Oxygen,Nitrogen,Argon

fprintf('Molecular weight of');
fprintf(Species_SP);
fprintf(':');
%standard atomic number
Atomic_Weight=[1.008 12.011 15.999 14.007 39.948];
%starting range of molecule
Molecularweight=0;

%Adding Atomic number to obtain particular value
for i=1:length(Species_SP)
for j=1:length(atomic_name)
if strcmpi(Species_SP(i),atomic_name(j))
Molecularweight=Molecularweight+Atomic_Weight(j);
position=j;
end
end
n=str2num(Species_SP(i));

if n>1

Molecularweight=Molecularweight+Atomic_Weight(position)*(n-1);
end
end

fprintf('molecular weight %s :',Species_SP);
fprintf('%d',Molecularweight);
disp(' ');
end

Main code:-

clear all
close all
clc

% Reading Data file -NASA Thermodynamic
% Open a file & 'r' open the file for reading
f1=fopen('THERMO.dat','r')
get=fgetl(f1);

%obtain temperatures - by reading header information
global_temp=fgetl(f1);

%spliting
t=strsplit(global_temp);

% converting string cells to numbers using str2num,
global_low_temp=str2num(t{2});
global_medium_temp=str2num(t{3});
global_high_temp=str2num(t{4});

%temperature range & gas constant
%temperature range assumed

%universal gas constant j/(mol-k)
R = 8.314;

%skipping three comment lines in the file
for i=1:3
gt=fgetl(f1);
end

for i=1:53
gt=fgetl(f1);
A=strsplit(gt,' ');
species_SP=(A{1});
low_localtemp=str2num(A{end-3});
mid_localtemp=str2num(A{end-1});
high_localtemp=str2num(A{end-2});
temp=linspace(low_localtemp,high_localtemp,500);
line_1=fgetl(f1);
a=strfind(line_1,'E');

%Extracting higher and lower temperature coefficients

% Extracting FIRST 7 coefficients i.e HIGH-temperature coefficients
a1=line_1(1:a(1)+3);
a1=str2num(a1); %1
a2=line_1(a(1)+4:a(2)+3);
a2=str2num(a2); %2
a3=line_1(a(2)+4:a(3)+3);
a3=str2num(a3); %3
a4=line_1(a(3)+4:a(4)+3);
a4=str2num(a4); %4
a5=line_1(a(4)+4:a(5)+3);
a5=str2num(a5); %5

line_2=fgetl(f1);
b=strfind(line_1,'E');
a6=line_2(1:b(1)+3);
a6=str2num(a6); %6
a7=line_2(a(1)+4:b(2)+3);
a7=str2num(a7); %7

%Ectracting SECOND 7cofficients - LOW-temperature cofficients
a8=line_2(b(2)+4:b(3)+3);
a8=str2num(a8); %8
a9=line_2(b(3)+4:b(4)+3);
a9=str2num(a9); %9
a10=line_2(b(4)+4:b(5)+3);
a10=str2num(a10); %10

line_3=fgetl(f1);
c=strfind(line_1,'E');

a11=line_3(1:c(1)+3);
a11=str2num(a11); %11
a12=line_3(c(1)+4:c(2)+3);
a12=str2num(a12); %12
a13=line_3(c(2)+4:c(3)+3);
a13=str2num(a13); %13
a14=line_3(c(3)+4:c(4)+3);
a14=str2num(a14); %14

%specific heat calculation
cp=specificheat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,temp,R,mid_localtemp);

%Enthalpy calculation
H=Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,temp,R,mid_localtemp);

%Entropy calculation
S=Entropy_calc(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,temp,R,mid_localtemp);

%calculating molecular weight of species
Molecularweight(i)=Molecular_weight(species_SP);

%Read & Write molecular list
Molecular_list=fopen('Molecular weight.txt','a+');
fprintf(Molecular_list,'molecular weight of %s is %d n',species_SP,Molecularweight);
fclose(Molecular_list);

%plotting(CP,H,S,Temp,Species_SP)

%Saving as a folder

mkdir('C:\Users\91630\Documents\MATLAB',species_SP);
cd(species_SP);

%Plot 1, specific heat (CP) vs Temperature range(Temp)

figure(1)
plot(temp,cp,'linewidth',2,'color','r');
xlabel('Temperature [K]');
ylabel('Specific Heat [kJ]');
title(sprintf('varying specific heat with temperature range of %s',species_SP));
grid on
saveas(figure(1),'Specific Heat.jpg');

%plot 2, Enthalpy (H) vs Temperature Range (Temp)

figure(2)
plot(temp,H,'linewidth',2,'color','g');
xlabel('Temperature [K]');
ylabel('Enthalpy in [kJ/(mol)]');
title(sprintf('varying Enthalpy with Temperature Range of %s',species_SP));
grid on
saveas(figure(2),'Ethalpy.jpg');

%plot 3, Entropy (S) VS Temperature Range(Temp)

figure(3)
plot(temp,S,'linewidth',2,'color','b');
xlabel('Temperature [K]');
ylabel('Entropy in [kJ/(mol-K)]');
title(sprintf('Varying Entropy with Temperature Range of %s',species_SP));
grid on
saveas(figure(3),'Entropy.jpg');

cd ..

%Molecular weight

M = Molecular_weight(species_SP)
f2=fopen('molecular mass','w');
fprintf('%s \n %f \n','species','Molecular mass',M)
fclose(f2)

end

fclose(f1)

Output for specific heat:-

Output for entrophy:-

Output for enthalpy:-

Syntax used during coding:-

Fopen: 

Open a file or obtain information about open files.

'r':- Open the file for reading

fgetl:- read line from file

strsplit:- split string or character vector at specified delimiter

str2num:- convert character array or string to numeric array

strfind:- find one string within another

linspace :- generate linearly spaced vectors

fprintf :- write formatted data to file

pwd :- identify current directory

mkdir:- make new directory 

cd :- change working directory

Results:-

specific heat , Entropy and Enthalpy plots for O2,N2,Co2 species:

1.plots for O2

Conclusion :-

Using MATLAB code the necessary coefficients required to evaluate various thermodnamic parameters for different species are extracted from NASA thermodynamic data file. The specific heat , entropy, enthalpy for all the species are calculated and plotted against the local temperature ranges. The molecular weight is calculated for all the species.