Challenge

Project 1 - Parsing NASA thermodynamic data

BBalaji Ragavan21 Aug 2022

Aims :

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

Objective :

1. 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.

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

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

4. 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.

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

6. Please write a detailed report to describe your logic.

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

8. Plots for o2, N2 and Co2 species (your program should be case insensitive, if it is going to take the species name as an input).

FILE PARSING :

Parsing a file means reading in a data stream and building a memory model of the content of that data. This aims at facilitating perfoming some kind of transformation on the data. Parsing splits a file or other input into pieces of data that can be easily stored or manipulated.

NASA Thermodynamic File:-

NASA thermodynamics file which is THERMO.dat file in which there are temperature range and different 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.

where as,

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 :

Specific heat, the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree. The units of specific heat are usually calories or joules per gram per Celsius degree.

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

Entropy :

It is a measure of the degree of randomness and disorder of the system.

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

Enthalpy :

Enthalpy is the measurement of energy in a thermodynamic system. The quantity of enthalpy equals to the total content of heat of a system, equivalent to the system's internal energy plus the product of volume and pressure.

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

CODE :

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%PROGRAM PROJECT 1, PARSING NASA THERMODYNAMIC DATA

%clear all

close all

clc

%Input

R=8.314; % Gas Constant

%Reading data file

%open file and reading THERMO.dat file

f1 = fopen('THERMO.dat','r');

get = fgetl(f1);

% Now Reading Temperature from this file

temp = fgetl(f1);

%spliting

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=fgetl(f1);

end

% Reading the Species

for j=1:53

tline=fgetl(f1);

A=strsplit(tline,' '); % spliting 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});

tlinel = fgetl(f1); % getting next line

a = strfind(tlinel,'E'); % Finding the string E

% Finding First 7 higher and second 7 lower

%Finding Higher coefficients

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

a1 = str2num(a1);

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

a2 = str2num(a2);

a3 = tlinel(a(2)+4:a(3)+3);

a3 = str2num(a3);

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

a4 = str2num(a4);

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

a5 = str2num(a5);

tline2 = fgetl(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 = fgetl(f1);

c = strfind(tline3,'E');

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

all = str2num(a11);

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

a12 = str2num(a12);

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

al3 = str2num(a13);

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

a14 = str2num(a14);

fprintf('%s',species);

% 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

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

% Calculate Molecular weight of the Species

wt = Molecular_weight(species);

% writing molecular weight file

cd('F:\SKILL LYNC\Challenges\Week 1.1');

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('F:\SKILL LYNC\Challenges\Week 1.1\species') % changing directory

mkdir(species); %creating directory

cd(species);

% Plot 1 Cp vs T

figure(1)

plot(T,Cp, 'linewidth',2,'color','b');

xlabel('Temperature(K)');

ylabel('Specific Heat(KJ)');

title(sprintf('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','r');

xlabel('Temperature');

ylabel('Entropy(KJ/mol-K)');

title(sprintf('Entropy vs Temperature range of %s',species));

grid on

saveas(figure(2), 'Entropy.jpg');

% Plot 3 Cp vs T

figure(3)

plot(T,H, 'linewidth',2,'color','g');

xlabel('Temperature');

ylabel('Enthalpy(KJ/mol)');

title(sprintf('Enthalpy vs Temperature range of %s',species));

grid on

saveas(figure(3), 'Enthalpy.jpg');

cd('F:\SKILL LYNC\Challenges\Week 1.1') %Changing directory to C

% Molecular weight

%W = Molecular_weight(species);

end

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STEP by STEP EXPLANATION :

1. Thermo.dat file is already given for this project. Before going to get data from it we have to do read and open the data first. By using fopen & fgetl command.

2. Then, we will spilt the temperature data using strsplit convert into cell array. Then will convert this string to number using str2num. To find the low, Mid & high temperature.

3. Then we assign temperature valve by using linspace command. And we will skip first 3 line then we will run loop by using fgetl command.

4. Now, we will run the loop 53 times to find the element in the data file by assigning fgetl command and then spliting into the cell array to find the species line and then find the species name and then find the number of the temperatures in the species line.

5. 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 by using str2num.

6. Out of 14 co efficient , first 7 coefficient are Higher Temperature and remaining lower 7 cofficient are lower temperature.

7. Now we will mention 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 the Molecular weight of the different species.

8. Then we will write the Molecular weight.txt file and fprintf all the molecular weights of the species.

9. And then close the txt file using fclose command.

10. 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.

11. Finally, we will plot Specific heat, Entropy and Enthalpy with the Temperature for different species. We we will use scanf command to in the title command.

12. Last step we will saveas command to save the plot of different species.

Function 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 repectively

if (T <= tempmid)

Cp = R*(a8 + (a9*T) + (a10* (T).^2) + (a11*(T).^3) + (a12*(T).^4));

else

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

end

STEPS :-

1. To find the Specific heat by creating Specific heat function and assigning the formula coefficent from 14 coefficients, Gas constant, Temperature and mid temperature.

2. Then we will creatre an condition using if loop and make the temperature less than and equal to mid temperature to specify lower temperature coefficent in the formula.

3. Then we will use else condition to specify coefficient of Higher temperature coefficent in the formula.

4. Then end the loop and function to calculate Specific Heat.

Function to find Entropy:

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

% calculating entropy % calculating entropy for higher and lower temperature repectively.

if (T <= tempmid)

S = R*(a8.*log(T) + (a9*T) + ((a1e*(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

STEP :

1. First to find the Entropy by Entropy function and same as above to assigning its relted formula coefficent from 14 coefficients, Gas constant, Temperature and mid temperature.

2. Then we will creatre an condition using if loop and make the temperature less than and equal to mid temperature to specify lower temperature coefficent in the formula.

3. Again we will use else condition to specify coefficient of Higher temperature coefficent in the formula.

4. Finnally end the loop and function to calculate Entropy.

Function to find Enthalpy:

function H = enthalpy (a1, a2, a3, a4, a5, a6, a8, a9, a10, a11, a12, a13,T, R, tempmid)

% calculating enthalpy % calculating enthalpy for higher and lower temperature repectively.

if (T <= tempmid)

H = R*T.*(a8 + ((a9*T)/2) + ((a10* (T).^2)/3) + ((a11*(T).^3)/4) + ((a12*(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

STEP :

1. First we will find the Enthalpy by creating Enthalpy function and same as above assigning its relted formula coefficent from 14 coefficients, Gas constant, Temperature and mid temperature.

2. Then we will creatre an condition using if loop and make the temperature less than and equal to mid temperature to specify lower temperature coefficent in the formula.

3. Again we will use else condition to specify coefficient of Higher temperature coefficent in the formula.

4. Finnaly end the loop and function to calculate Enthalpy.

Defining Atomic masses of main species

atomic_weight = [1.008 12.011 15.999 14.007 39.948];

wt=0; % Molecular weight starting range

for i=1:length(species) % Loop runs to the length of the species

for j=1:length(atomic_name) % Loop runs to the length of the atomic name

if strcmp(species(i), atomic_name(j)) %function to compare 2 strings

wt = wt + atomic_weight(j);

position = j;

end

n = str2num(species); % Now we will find if there is more element

if n>1

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

end

fprintf('Molecular weight of %s :- ', species);

fprintf('%f',wt);

disp(' ')

end

STEPS :

1. First we will create an Molecular weight function wt and assigning species input to that.

2. Then define the main element of all 53 species in an array atomic_name that are :- 'H','C','O','N','Ar'.

3. Then by taking above main elements we will create there atomic_wieght array that are : 1.008 12.011 15.999 14.007 39.948.

4. Then we will assign molecular starting range wt = 0. To zero and then create an for loop condition which runs to the length of the species and an another nested for loop is created which runs to the length of the string atomic_name.

5. Then we will create an condition using if condition and use strcmp command to compare the species and atomic_name strings to calculate molecular masses if by comparison both string found same then we will assign its molecular weight.

6. Now, we will string to the number using str2num command assign to n. Then we run an condition of if loop to find weather the species contains more than one element if there are more then 1 elements that is n>1 then we will increment the atomic weight by the multiplication of position and n-1 to the atomic_weight array.

7. Finnaly, we will print the Molecular weight using fprintf command and display using disp command.

ERRORS :

Bellow errror I faced due to close parenthesis is missed in function program.

After assigning the parenthesis its resolved.