Project 1 - Parsing NASA thermodynamic data
AIM: To write a code in Matlab to parse the NASA thermodynamic data file and calculate the thermodynamic properties of various gas species
OBJECTIVE:
Write a function that extracts the 14 coefficients and calculates the enthalpy, entropy, and specific heats for all the species in the data file.
The formula for specific heat(Cp), enthalpy(H), and entropy(S) are given below;
Where R is the universal gas constant, T is the temperature
The FIRST 7 coefficients are HIGH-temperature coefficients and the SECOND 7 coefficients are LOW-temperature coefficients.
To 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.
To save the plots as images with appropriate names and dump them in separate folders for each species with a suitable name. All these should be generated automatically.
THEORY:
NASA THERMODYNAMIC FILE:
The NASA thermodynamic file (THERMO.dat) contains data of 53 species and each species contains 14 coefficients and temperature ranges. We have to find these 14 coefficients to find specific heat, enthalpy and entropy
where,
R - Universal gas constant
T - Temperature
Cp - Specific heat[K]
H - Enthalpy(KJ/mol)
S - Entropy(KJ /mol-K)
FILE PARSING:
Parse: To parse data or information means to break it down into component parts so that its syntax can be analyzed, and understood
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 formal grammar.
Parsing a file means reading in a data stream of some sort and building an in a memory model of the semantic content of the data. This aims at facilitating performing some kind of transformation on the data.
SPECIFIC HEAT: is the quantity of heat required to raise the temperature of one gram of a substance by one Celcius degree.
%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 coefficiients 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));
end
steps:
We find the Specific heat by creating a separate specific heat function and assigning its related formula coefficient from the 14 coefficients that we found out,Gas constant, Temperature, and medium temperature
Now we create a condition using the if loop and make temperature less than and equal to medium temperature to specify the lower temperature coefficients in the formula
The else condition is used to specify coefficient of higher temperature coefficient in the formula
Then end the loop and function to calculate the Specific heat of species
ENTROPY: is 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
% Entropy calculation
function S = Entropy_calc(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,Temp, R,global_medium_temp);
%copmparing with global temperature
%if less than global temperature - minimumcoefficients 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
S = R.*(a1.*log(Temp)+(a2.*Temp) +(a3*((Temp).^2)/2)+(a4*((Temp).^3)/3)+a5*((Temp).^4)+a7);
end
steps:
We find the Entropy by creating a separate specific heat function and assigning its related formula coefficient from the 14 coefficients that we found out,Gas constant, Temperature, and medium temperature
Now we create a condition using the if loop and make temperature less than and equal to medium temperature to specify the lower temperature coefficients in the formula
The else condition is used to specify coefficient of higher temperature coefficient in the formula
Then end the loop and function to calculate the Entropy of species
ENTHALPY: is the sum of the system's internal energy and the product of its pressure and volume.
%Enthalpy calculation
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
H = R*Temp.*(a1 + ((a2*Temp)/2)+((a3*(Temp).^2)/3)+((a4*(Temp).^3)/4)+((a5*(Temp).^4)/5)+((a6./Temp)));
end
steps:
We find the Enthalpy by creating a separate specific heat function and assigning its related formula coefficient from the 14 coefficients that we found out,Gas constant, Temperature, and medium temperature
Now we create a condition using the if loop and make temperature less than and equal to medium temperature to specify the lower temperature coefficients in the formula
The else condition is used to specify coefficient of higher temperature coefficient in the formula
Then end the loop and function to calculate the Enthalpyt of species
MOLECULAR WEIGHT: Molecular weight is a measure of the sum of the atomic weight values of the atoms in a molecule. Molecular weight is used in chemistry to determine stoichiometry in chemical reactions and equations. Molecular weight is commonly abbreviated by M.W. or MW. Molecular weight is either unitless or expressed in terms of atomic mass units (amu) or Daltons (Da).
% Molecular weight calculation
function W = Molecular_weight(species)
atomic_name = ['H','C','O','N','Ar'];
atomic_weight = [1.008 12.011 15.999 14.007 39.948];
W = 0;
for i = 1:length(species)
for j = 1:length(atomic_name)
if strcmp(species(i),atomic_name(j))
W = W +atomic_weight(j);
position = j;
end
end
n= str2double(species);
if n>1
W = W + atomic_weight(position)*(n-1);
end
end
end
Steps:
Firstly we create a Molecular_weight function W and assign species as input to the function
Then we define the main elements of the 53 species n an array named atomic_name
Corresponding to the main elements we create an array atomic_weight and specify their atomic weights
Then we assign the Molecular_weight starting range to zero i.eW = 0
Further, we create a condition using if condition Inside the if condition we use strcmp command to compare the species and atomic_name strings to calculate the molecular masses
If by comparison both strings are found the same then we will assign their molecular weight.
After that, we utilize the str2double command and assign it to n
If there is more than one element i.e n>1 we use the if condition
MAIN CODE:
clear all
close all
clc
%input
R = 8.314; % gas constant
%reading the data file
% open fileand read THERMO.dat
f1 = fopen('THERMO.dat','r');
get = fgetl(f1);
%reading temp
%splitting
global_temp = fgetl(f1);
t = strsplit(global_temp);
%converting string to number
global_low_temp = str2num(t{2});
global_medium_temp = str2num(t{3});
global_high_temp = str2num(t{4});
%temperature range
Temp = linspace(global_low_temp,global_high_temp,1000);
%skipping comment lines
for i = 1:3
get = fgetl(f1);
end
%reading the species
for j = 1:53
tline = fgetl(f1);
A = strsplit(tline,' ');
species = (A{1});
line_1 = fgetl(f1);
a = strfind(line_1,'E');
% EXTRACTING THE COEFFICIENTS
a1 = line_1(1:a(1)+3);
a1 = str2num(a1);
a2 = line_1(a(1)+4:a(2)+3);
a2 = str2num(a2);
a3 = line_1(a(2)+4:a(3)+3);
a3 = str2num(a3);
a4 = line_1(a(3)+4:a(4)+3);
a4 = str2num(a4);
a5 = line_1(a(4)+4:a(5)+3);
a5 = str2num(a5);
line_2 = fgetl(f1);
b = findstr(line_2,'E');
a6 = line_2(1:b(1)+3);
a6 = str2num(a6);
a7 = line_2(b(1)+4:b(2)+3);
a7 = str2num(a7);
a8 = line_2(b(2)+4:b(3)+3);
a8 = str2num(a8);
a9 = line_2(b(3)+4:b(4)+3);
a9 = str2num(a9);
a10 = line_2(b(4)+4:b(5)+3);
a10 = str2num(a10);
line_3 = fgetl(f1);
c = findstr(line_3,'E');
a11 = line_3(1:c(1)+3);
a11 = str2num(a11);
a12 = line_3(c(1)+4:c(2)+3);
a12 = str2num(a12);
a13 = line_3(c(2)+4:c(3)+3);
a13 = str2num(a13);
a14 = line_3(c(3)+4:c(4)+3);
a14 = str2num(a14);
% CALCULATION OF VARIOUS PARAMETERS
Cp = Specificheat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,Temp,R,global_medium_temp);
H = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,Temp,R,global_medium_temp);
S = Entropy_calc(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,Temp,R,global_medium_temp);
cd('C:\Users\TIGER\Documents\MATLAB\Matlab programs\parsing_project')
mkdir(species);
cd(species)
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));
grid on ;
saveas(figure(1),'specific Heat,jpg');
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));
grid on
saveas(figure(2),'Enthalpy,jpg');
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));
grid on
saveas(figure(3),'Entropy,jpg');
cd ..
W = Molecular_weight(species);
sprintf('Molecular weight of %s = %f',species,W)
end
OUTPUT: PLOTS
Plot for 02
Plot for N2
Plot for C02
Screenshot of the directory where different species are saved:
Output of Molecular weight of the different species:
