Project 1 - Parsing NASA thermodynamic data

PARSING NASA THERMODYNAMIC DATA

Aim :

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

Objective :

• 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 temeprature

• The FIRST 7 coefficients are HIGH-temperature coefficients and the SECOND 7 coefficients are LOW-temperature coefficients.

• Also use the LOCAL TEMPERATURE RANGES which is unique for each individual species, not the GLOBAL TEMPERATURE RANGE.

• 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 (low temperature : high temperature) specific for each species.

• Save the plots as images with appropriate names and dump them in separate folders for each species with suitable name. All these should be generated automatically.

• The main program that you will submit will just take the "THERMO.dat" file as an input and generate Cp, H and S plots.

• Please write a detailed report to describe your logic.

• Screenshot of the window where all the folders are saved.

• Plots for o2, N2 and Co2 species .

File parsing :

• Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar.

• The term parsing comes from Latin pars (orationis), meaning part (of speech).W hin computational linguistics the term is used to refer to the formal analysis by a computer of a sentence or other string of words into its constituents, resulting in a parse tree showing their syntactic relation to each other, which may also contain semantic and other information. Some parsing algorithms may generate a parse forest or list of parse trees for a syntactically ambiguous input.

• Parsing a file means reading in a data stream of some sort and building an in memory model of the semantic content of that data. This aims at facilitating perfoming some kind of transformation on the data.

NASA Thermodynamic File:

• NASA thermodynamics file which is THERMO.dat file in which there are temperature range and 53 species are given in these data and each species contains 14 coefficients and temperature ranges and we have to parse these 14 coefficients to find Specific heat, Entropy and Enthalpy using formula as:

where,

• R = Universal Gas constant
• T = Temperature
• Cp = Specific heat (KJ)
• S = Entropy(KJ/mol-K)
• H = Enthalpy(KJ/mol)
• a(i) = Coefficients where, i = 1 to 14

Specific Heat:

• The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.
• The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat.

Cp = R*(a1 + (a2*T) + (a3*(T).^2)+ (a4*(T).^3) + (a5*(T).^4))

Entropy :

• Entropy, the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work. Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system.

S = R*(a1.*log(T) + (a2*T) + ((a3*(T).^2)/2) + ((a4* (T).^3)/3) + ((a5*(T).^4)/4) + a7)

Enthalpy:

• Enthalpy, a property of a thermodynamic system, is equal to the system's internal energy plus the product of its pressure and volume. In a system contained so as to prevent mass transfer, for processes at constant pressure, the heat absorbed or released equals the change in enthalpy.

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

Program code :

Function code :

1.Specific heat :

% Specific heat calculation function

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

2.Entropy :

% Entropy Calculatin function

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

3.Enthalpy :

% Enthalpy Calculation function

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

4.Molecular Weight :

% Molecular Weight Calculation function

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

% Make directory
mkdir 'D:f'

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

% Obtaing 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
Temp=linspace(global_low_temp,global_high_temp,1000);
% 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})

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

% Extracting SECOND 7 coefficients - LOW-temperature coefficients
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,global_medium_temp);

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

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

% 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

cur_dir=pwd;
mkdir(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(cur_dir);

% Molecular weight

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

CODE EXPLANATION :

• 'clear all' - clear all the variables in the workspace,
• 'close all' - closes all the plots and figures and
• 'clc' clears the command window.
• Making a directory using 'mkdir' with location address.
• After that, reading the text file 'Thermo.dat' file and opening it by using 'fopen' and 'r' as reading command.
• For reading the line in a text file using 'fgetl'.
• To obtain the temperature range from the Thermo.dat file, using 'strsplit' to split the temperature into a particular string cell.
• Used 'str2num' for converting string cell to numbers.
• Divided the temperature into a string and then converted to a number so that temperature values can be used separately to solve the NASA thermodynamics.
• Using 'for & end' loops to skip the next three comment lines in the text file.
• Reading all the 53 species to plot specific heat(cp), enthalpy (H), and entropy(S), with temperature values, and to find the molecular weights.
• Used 'for' loop to read 53 species.
• Used 'strfind' to find string.
• Using 'linspace' specified the temperature range from low to high.
• Adding universal gas constant value 'R.
• Extracted higher and lower temperature coefficient by reading line by line from the species.
• Calling specific heat, enthalpy, entropy function codes. 16. Calculating Molecular weight.

Syntax Used during Coding

Fopen :Open a file or obtain information about open files

'r' :Open the file for reading

fgelt :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,Enthalpy Plots for O2,N2 and CO2 Species .

1.Plots for O2:

2.Plots for N2 :

3.Plots for CO2:

Attachmend file Screenshot :

Display it in the command window :

Conclusion :

• Using MATLAB code, the necessary coefficients required to evaluate various thermodynamic parameters for different species are extracted from NASA thermodynamic data file.

• The specific heat, enthalpy, and entropy for all the species are calculated and plotted against the local temperature range.

• The molecular weight is calculated for all the species.

Google Drive link :

https://drive.google.com/file/d/1BgIbpntLAy_qTNAJUOAnmi-uZBsDcwlJ/view?usp=sharing

References:

https://in.mathworks.com/help/matlab/ref/mkdir.html

https://in.mathworks.com/matlabcentral/answers/317006 create-new-folders-by-mkdir

https://in.mathworks.com/help/matlab/ref/saveas.html

https://in.mathworks.com/matlabcentral/answers/17580-how to-define-a-path-in-saveas-command