Project 1 - Parsing NASA thermodynamic data

Aim: 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.
• 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 dumpo 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.
• 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 analysing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of formal grammar. The term parsing comes from Latin pars (orationis) meaning part(of speech). Within 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 data stream of some sort and building an in memory model of the semantic content of that data. This aims at facilitating performing some kind of transformation on data.

NASA Thermodynamic file:

NASA thermodynamic 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).^2) +(a5*(T).^2)

Entropy:

Entropy, the measure of 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)

Entalpy:

Entalpy, 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)))

Code:

clear all

close all

clc

%Input

R=8.314; % Gas constant

% Reading data file

% open file and reading THERMO.dat file

f 1 = fopen(‘THERMO.dat’,’r’)

get = fget1(f1)

% Now reading temperature from this file

temp = fget1(f1);

%splitting

s = strsplit(temp);

%converting strings cells into numbers

templow = str2num(s{2});

tempmid = str2num(s{3});

temphigh = str2num(s{4});

% Temperature range

T = linspace(templow,temphigh,1000);

%Skipping comment lines

for i = 1:3

get = fget1(f1);

end

% Reading the species

for j = 1:53

tline = fget1(f1);

A = strsplit(tline,’ ‘); %splitting into cell array

species = (A{1}); %To read the name of the species

% Converting string to number

lowtemp = str2num(A{end-3});

midtemp = str2num(A{end-2});

hightemp = str2num(A{end-1});

tline1 = fget1(f1); %getting next line

a = strfind(tline1,’E’); %Finding the string E

% Finding first 7 higher and second 7 lower coefficients

%Finding higher coefficients

a1 = tline1(1:a(1)+3);

a1 = str2num(a1);

a2 = tline1(a(1)+4:a(2)+3);

a2 = str2num(a2);

a3 = str2num(a3);

a4 = tline1(a(3)+4:a(4)+3);

a4 = str2num(a4);

a5 = tline1(a(4) + 4:a(5) + 3);

a5 = str2num(a5);

tline2 = fget1(f1);

b = strfind(tline2,’E’);

a6 = tline2(1:b(1)+3);

a6 = str2num(a6);

a7 = tline2(b(1) + 4:b(2)+3);

a7 = str2num(a7);

%Finding lower coefficients

a8 = tline2(b(2)+4:b(3)+3);

a8 = str2num(a8);

a9 = tline2(b(3)+4:b(4) +3);

a9 = str2num(a9);

a10 = tline2(b(4)+4:b(5) +3);

a10 = str2num(a10);

tline3 = fget1(f1);

c = strfind(tline3,’E’);

a11 = tline3(1:c(1)+3);

a11 = str2num(a11);

a12 = tline3(c(1) + 4:c(2) + 3);

a12 = str2num(a12);

a13 = tline3(c(2) + 4:c(3) + 3);

a13 = str2num(a13);

a14 = tline3(c(3) + 4:c(4) + 3);

a14 = str2num(a14);

% Calculate specific heat

Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid);

%Calculate Entropy

S = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid);

%Calculate Enthalpy

S = Enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,T,R,tempmid);

%Calculate molecular weight of the Species

W = Molecular_weight(species);

%writing molecular weight file

MW_file = fopen(‘Molecular Weight.txt’,’w’);

fprintf(MW_file,’Molecular weight of %s is %d’, species, W);

fclose(MW_file); % Closing the file

% Plotting Cp, H and S with temperature

% Saving in a folder

cd(‘E:\Matlab Programs’) % changing directory

mkdir(species); % creating directory

cd(species);

%Plot1 Cp vs T

figure(1)

plot(T,Cp,’linewidth’,2,’color’,’b’);

xlabel(‘Temperature(K)’);

ylabel(‘Specific Heat(KJ)’);

title(sprint(‘Specific heat vs Temperature Range of %s’, species));

grid on

saveas(figure(1),’Specific Heat.jpg’);

% Plot 2 S vs T

figure(2)

plot(T,S,’linewidth’,2,’color’,’b’);

xlabel(‘Temperature(K)’);

ylabel(‘Entropy(KJ/mol-K’);

title(sprint(‘Entalpy vs Temperature Range of %s’, species));

grid on

saveas(figure(2),’Entropy.jpg’);

% Plot 3 Cp vs T

figure(2)

plot(T,H,’linewidth’,2,’color’,’b’);

xlabel(‘Temperature’);

ylabel(‘Entropy(KJ/mol’);

title(sprint(‘Entalpy vs Temperature Range of %s’, species));

grid on

saveas(figure(3),’Enthalpy.jpg’);

cd(‘E:\Matlab Programs’) % changing directory

% Molecular Weight

W = Molecular_weight(species)

end

Steps:

• Firstly we will input the parameter R and we will open a file THERMO.dat file and reading this file using fopen command.
• Then we will read first THERMO using fgetl command and then we read temperature file and we will split the temperatures using strsplit command to convert it into cell array and then we will convert this string to number using str2num command to find low, high and mid temperatures.
• Then we will assign temperature range using linspace command. Then we run loop to skip command lines the data file using fgetl command inside the loop.
• Now we will run the loop to find 53 elements in the data file by assigning fgetl command and then splitting into the cell array to find the species line and then find the species name and then find the number of temperatures in the species line.
• Then we read a new line. In order to read the coefficient in the data file we will first find the ‘E’ string using strfind command to find before and after numbers of the coefficients then we will find remaining 14 coefficients and convert them to numbers from strings.
• Out of which we will find first 7 coefficients which are for higher temperature and then second 7 coefficients which are ofr lower temperature.
• Now we will specify specific heat Cp, Entropy S, Enthalpy H functions to find these parameters using these 14 coefficients for lower and higher temperature then we will specify molecular weight W function to find Molecular Weight of different species.
• Now we will write the Molecular Weight.txt file and fprintf all the molecular weights of the species and then close txt file using fclose command.
• Now we change the directory using cd command and then creating directory folder where we have to save our files using mkdir command and then we will change the directory to this created folder.
• Now we will plot specific heat, Entropy, and Enthalpy with temperature for different species. We will use scanf command to in the title command to create different species title.
• Then we will use saveas command to save the plots of different species in the directory folder.Now we will change the directory to which our main code file runs in the MATLAB.

Functions to find specific heat:

function Cp = Specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid)

%calculating specific heat

%calculating specific heat for higher and lower temperature respectively.

if( T<= tempmid)

Cp = R*(a8 + (a9*T) + (a10*(T).^2) + ((a11*(T).^3) + ((a11*(T).^4);

else

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

end

end

Function to find entropy:

function S = Entropy(a1,a2a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid)

% calculating entropy

%calculating entropy for higher and lower temperature respectively

if (T<= tempmid)

S = R*(a8.*log(T) + (a9*T) + ((a10*(T).^2/2) + ((a11*(T).^3/3) + ((a12*(T).^4/4) + a14);

else

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

end

end

Function to find Enthalpy:

function H = Enthalpy(a1,a2a3,a4,a5,a6,a8,a9,a10,a11,a12,T,R,tempmid)

% calculating entropy

%calculating entropy for higher and lower temperature respectively

if (T<= tempmid)

H = R*T.*(a8 + ((a9*T)/2) + ((a10*(T).^2)/3) + ((a11*(T).^3/4) + ((a11*(T).^4/5) + ((a13./T))

else

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

end

end

Function to find Molecular weight of the different species:

Function W = Molecular_weight(species)

% Defining atomic name of the species

atomic_name = [‘H’,’C’,’O’,’N’,’Ar’];

%Defining Atoimic masses of main species

atomic_weight = [1.008 12.011 15.999 14.007 39.948];

W = 0; % Molecular weight starting range

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 = str2num(species);

if n>1

W = W + atomic_weight(position)*(n-1);

end

end

fprintf(‘Molecular Weight of %s :- ‘, species);

fprintf(‘%f’,W);

disp(‘ ‘)

end

Final Results:

Plots:

Plot of species O2:

Plot of species N2:

Plot of species CO2: