Project 1 - Parsing NASA thermodynamic data

Aim:

To write a code in MATLAB to parse the NASA thermodynamic data file and then calculate the Thermodynamic properties, Molecular Weight and Plot nature of the thermodynamic properties of various species.

Objectives:

1. To write a function that extracts the 14 co-efficient for a given species from the given species

2. To write functions that calculate the enthalpy, entropy and specific heat using the NASA polynomials for the given species

3. To write a function that plots the Cp, Enthalpy, and Entropy of an input species.

4. To write a function that calculates the molecular weight of each species.

Introduction:

1) Parsing

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, in other words, file parsing refers to how information can be read from a particular teste or any type of file and how that information can be used to in a computer program Test parsing is a common programming task that splits the given sequence of characters or values(test) into smaller parts based on some rules it has been used in a wide variety of applications ranging from simple fe posing to large scale natural language processing. For example, NASA come up with polynomials such as CpH and S. They have also documented the coefficients that are required to evaluate these polynomials for 1000+ species.

2) NASA Thermodynamic Data:

THERMO.dat tile is a data file containing 14 coefficients for 53 different elements given by NASA These coefficients are used to calculate the enthalpy entropy and specific heats for all the species in the data file. Each species o has its own range of local temperatures.

3) Specific Heat Capacity (Cp) :

Specific Heat capacity is the amount of heat to be supplied to(or taken out) of the unit more of a system in order to increase(or decrease) its temperature by one degree in a thermodynamic process in which quantity X is imposed.

4) Enthalpy. H(kJ):

It is a thermodynamic quantity equivalent to the total heat content of a system, it is equal to the internal energy of the system plus the product of pressure and volume.

5) Entropy S (kJ/k):

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

Main Program:

clear all
close all
clc

f1 = fopen('THERMO.dat','r');
fgetl(f1);
pline = fgetl(f1);
B = strsplit(pline,' ');
global_low_temp = str2num(B{2});
global_medium_temp = str2num(B{3});
global_high_temp = str2num(B{4});
fgetl(f1);
fgetl(f1);
fgetl(f1);

for m = 1:53

% Getting the Temperature.
tline = fgetl(f1);
K = strsplit(tline,' ');
sp = (K{1});
local_low_tem = str2num(K{end-3});
local_high_tem = str2num(K{end-2});
local_medium_tem = str2num(K{end-1});

% Getting the Coefficient 1
coeff_1 = fgetl(f1);
c = findstr(coeff_1,'E');
coeff_1(1:12+3);

c1 = str2double(coeff_1(1:c(1)+3));
c2 = str2double(coeff_1(c(1)+4:c(2)+3));
c3 = str2double(coeff_1(c(2)+4:c(3)+3));
c4 = str2double(coeff_1(c(3)+4:c(4)+3));
c5 = str2double(coeff_1(c(4)+4:c(5)+3));

% Getting the Coefficient 2
coeff_2 = fgetl(f1);
d = findstr(coeff_2,'E');
coeff_2(1:12+3);

c6 = str2double(coeff_2(1:d(1)+3));
c7 = str2double(coeff_2(d(1)+4:d(2)+3));
c8 = str2double(coeff_2(d(2)+4:d(3)+3));
c9 = str2double(coeff_2(d(3)+4:d(4)+3));
c10 = str2double(coeff_2(d(4)+4:d(5)+3));


% Getting the Coefficient 3
coeff_3 = fgetl(f1);
e = findstr(coeff_3,'E');
coeff_3(1:12+3);

c11 = str2double(coeff_3(1:e(1)+3));
c12 = str2double(coeff_3(e(1)+4:e(2)+3));
c13 = str2double(coeff_3(e(2)+4:e(3)+3));
c14 = str2double(coeff_3(e(3)+4:e(4)+3));

T = linspace(local_low_tem,local_high_tem,1000);
Tmid = [local_medium_tem];
R = 8.314;
[CP,H,S] = dinesh(T,Tmid,R,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14);


% PLOTTING TEMPERATURE & cp
figure(1)
plot(T,CP,'linewidth',3,'Color','r');
xlabel('Temperature');
ylabel('Specific Heat');
title('Temperature vs Specific Heat');

% PLOTTING TEMPERATURE & S
figure(2)
plot(T,S,'linewidth',3,'Color','g');
xlabel('Temperature');
ylabel('Entropy');
title('Temperature vs Entropy');

% PLOTTING TEMPERATURE & H
figure(3)
plot(T,H,'linewidth',3,'Color','b');
xlabel('Temperature');
ylabel('Enthalpy');
title('Temperature vs Enthalphy');

% saving the plots
mkdir(sp);
cd(sp);

saveas(figure(1),'species plot1.jpg');
saveas(figure(2),'species plot2.jpg');
saveas(figure(3),'species plot3.jpg');
cd ..

[mol_weight_cal] = molecular_weight(sp);


end

Program Explanation:

Initially, the file has been opened by using the command fopen.

And then the data has been extracted from the given file. Then the fgetl(f1) command is used to skip the first lines in the file.

pline = fgetl(f1);

B = strsplit(pline,' ');

global_low_temp = str2num(B{2});

global_medium_temp = str2num(B{3});

global_high_temp = str2num(B{4});

The temperature has been stored in the form of a string variable The string variable cannot be used for calculation as they are in the text The str2num command is used to store the temperatures.

fgetl(f1);

fgetl(f1);

fgetl(f1);

Then the fgetl(f1) command is used to skip the next three lines in the file.

for m = 1:53

% Getting the Temperature.

tline = fgetl(f1);

K = strsplit(tline,' ');

sp = (K{1});

local_low_tem = str2num(K{end-3});

local_high_tem = str2num(K{end-2});

local_medium_tem = str2num(K{end-1});

getting the 6 line using strsplit command we delete the spaces & assigning the species name with sp and then the lower temp. middle temp. higher temp has been used assigned using str2num because we are converting the string into numbers for using it in the formula for calculation.

% Getting the Coefficient 1

coeff_1 = fgetl(f1);

c = findstr(coeff_1,'E');

coeff_1(1:12+3);

To find the position of the E the findstr command is used throughout the data and in all assigned coefficient

c1 = str2double(coeff_1(1:c(1)+3));

c2 = str2double(coeff_1(c(1)+4:c(2)+3));

c3 = str2double(coeff_1(c(2)+4:c(3)+3));

c4 = str2double(coeff_1(c(3)+4:c(4)+3));

c5 = str2double(coeff_1(c(4)+4:c(5)+3));

using the str2double command we convert the string value into the number with precision.

Then using this same principle we are finding all 14 coefficients of "0" species.

T = linspace(local_low_tem,local_high_tem,1000);

Tmid = [local_medium_tem];

R = 8.314;

We have used T as an array by splitting the values as 1000

The value of universal gas constant R is 8314 (molk)

[CP,H,S] = dinesh(T,Tmid,R,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14)

To make code easier calling functions have been used.

Then we are calculating the S, H & Cp for all gas species.

% PLOTTING TEMPERATURE & cp

figure(1)

plot(T,CP,'linewidth',3,'Color','r');

xlabel('Temperature');

ylabel('Specific Heat');

title('Temperature vs Specific Heat');

The temperature & specific heat is plotted using plot command. X label, Y label, Title are named in the figure(1).

Then we are same principle for figure(2), figure(3). Then the graph has been plotted between temperature and specific heat entropy and enthalpy.

% saving the plots

mkdir(sp);

cd(sp);

Then the plots are saved by mkdir command which is used to make a folder.

The cd command is used to change the current folder to create a new folder.

saveas(figure(1),'species plot1.jpg');

saveas(figure(2),'species plot2.jpg');

saveas(figure(3),'species plot3.jpg');

We are saving the graph results in jpg format for the specific species.

cd...

going back to the original location for generating a new species creation.

[mol_weight_cal] = molecular_weight(sp);

To make code easier calling functions have been used.

Then we are calculating the Molecular weight of each species

end

it closes the for loop for m = 1:53.

Function for calculating CP, H & S

function [CP,H,S] = dinesh(T,Tmid,R,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14)
R = 8.314;

if T<= Tmid
    CP = ((c8) + (c9.*T) + (c10.*T.^2) + (c11.*T.^3) + (c12.*T.^4))*R;

    H = ((c8) + ((c9.*T)/2) + ((c10.*T.^2)/3) + ((c11.*T.^3)/4) + ((c12.*T.^4)/5) + (c13./T))*R;

    S = ((c8.*log(T)) + (c9.*T) + (c10.*T.^2)./2 + (c11.*T.^3)./3 + (c12.*T.^4)./4 + c14).*R;
    
else
    CP = ((c1) + (c2.*T) + (c3.*T.^2) + (c4.*T.^3) + (c5.*T.^4))*R;

    H = ((c1) + ((c2.*T)/2) + ((c3.*T.^2)/3) + ((c4.*T.^3)/4) + ((c5.*T.^4)/5) + (c6./T))*R;

    S = ((c1.*log(T)) + (c2.*T) + ((c3.*T.^2)./2) + ((c4.*T.^3)./3) + ((c5.*T.^4)./4) + c7).*R;

   
end
end

Program Explanation:

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

As per this requirement, we are using temperature from 0 to Tmid for the last 7 coefficients. Tmid to Tmax for the first 7 coefficients. using the if Command in MatLab.

In this function, we are defining the formula for Enthalpy, Entropy & Specific heat.

Function for calculating Molecular weight:

% calculating the Molecular weight

function mol_weight_cal = molecular_weight(sp)

species = sp;

elements = ['H','C','O','N','Ar'];

atomic_weight = [1.00794,12.0107,15.999,14.0067,39.948];

mol_weight_cal = 0;

for i = 1:length(species);
    for j = 1:length(elements);
        if species(i)==elements(j)
            mol_weight_cal=mol_weight_cal+atomic_weight(j);
            position = j;
        end
    end
    n = str2num(species(i));
    if n>1
        mol_weight_cal = mol_weight_cal + atomic_weight(position)*(n-1);
    end
    
end
    fprintf('Molecular weight of %s = %f',sp,mol_weight_cal);
    disp(' ')

end
​

Program Explanation:

This calling function code helps us to calculate the molecular weight of the various gases in the given NASA file.

The calculation of molecular weight is by assigning the atomic weight of the gases. Same as calculating S, H, Cp for loop has been used for calculation

Consider the Mw as 0 and put a range of length(species), and j range of length (elements).

And the command "if'' is used to compare the atomic weight and molecular weight of all species And then compare if (n>)) then the molecular weight of all gases has been calculated.

Final Result After Running the Main code:

Screenshots of Graph between (Temperature vs Specific Heat, Entropy, Enthalpy).

Plots Results:

O2:

Temperature vs Specific Heat

Temperature vs Entropy

Temperature vs Enthalpy:

N2

Temperature vs Specific Heat

Temperature vs Entropy

Temperature vs Enthalpy:

CO2:

Temperature vs Specific Heat

Temperature vs Entropy

Temperature vs Enthalpy:

Command Window Output:

Conclusion:

From the NASA thermodynamic file, the MATLAB code is developed by extensive research & development. The file parsing various MATLAB functions for various tasks, alternatives to make the code easy and efficient Comments have been added at all the required places. At last, errors were detected and various methodologies were practised to resolve the errors. The different plots for each element show the relation is a trend between the thermodynamic properties like specific heat, enthalpy & entropy with respect to temperature.

Attachment files.