Project 1 - Parsing NASA thermodynamic data

Aim : write a code in matlab to parse the NASA thermodynamics data file and then calculate thermodynamics properties of various gas species

Objective:

• Write a function that extracts the 14 coefficient and calculates the enthalpy entropy and specific heat of all the species in the data files.
• 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 plot as images with the approriate names and dump them in seperate folders for each species with the 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.
• Screen shot of the window where all the folders are saved.
• Plots for o2,N2 and co2 species.

File parsing:-

Parsing, syntex analysis or syntactic analysis is the process of analysing a string of symbols,either in natural language, computer language or data structure l, confirming to the rules of a formal grammer. 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 l, resulting in a parse tree showing there syntax reaction to each other, which may also contain semantic and other information. Some parsing algorithm may generate a parse forest or list of parse trees for a syntactically ambiguous inputs.

Parsing anfile means reading in a data stream of some sort and building an in memory model of a semantic content of that data.this aim at facilitating performing some kind of transformation on the data.

NASA thermodynamics 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 coefficient and temperature ranges and we have to parse these 14 coefficients to find specific heat ,enthalpy and entropy using formula as :-

Where ,

R = universal gas constant

T= temperature

Cp =specific heat (kj)

S = entropy (kj/mol-k)

H = enthalpy (kj/mol-k)

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 celcius.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 , property of a thermodynamic system , is equal to the system's internal energy plus the product of its volume and pressure.in a system contained so as the system mass transfer, for process 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 :-

MAIN CODE :-

clear all 
close all 
clc 

%inputs
%gas constant 
R = 8.314;

%reading the 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 = str2double(s{2});
tempmid = str2double(s{3});
temphigh =str2double(s{4});




%skipping comments lines 
for i = 1 : 3
    get = fgetl(f1);
end

%reading the species 
for j = 1:53
    tline = fgetl(f1);
   
    %splitting into cell array 
    A = strsplit(tline,' ');
    
    %to read the name of the species 
    species = (A{1});

    %converting string into number 
    lowtemp = str2double(A{end-3});
    midtemp = str2double(A{end-2});
    hightemp = str2double(A{end-1});
    %temperature Range 
    T = linspace(lowtemp,hightemp,1000);
    %getting next line
    tline1 = fgetl(f1);
    %finding the string E
    a = strfind(tline1,'E');

    %finding first 7 higher and second 7 lower coefficients 
    %finding higher coefficient 
    a1 = tline1(1:a(1)+3);
    a1 = str2double(a1);
    a2 = tline1(a(1)+4:a(2)+3);
    a2 = str2double(a2);
    a3 = tline1(a(2)+4:a(3)+3);
    a3 = str2double(a3);
    a4 = tline1(a(3)+4:a(4)+3);
    a4 = str2double(a4);
    a5 = tline1(a(4)+4:a(5)+3);
    a5 = str2double(a5);

    tline2 = fgetl(f1);
    b = strfind(tline2,'E');
    a6 = tline2(1:b(1)+3);
    a6 = str2double(a6);
    a7 = tline2(b(1)+4:b(2)+3);
    a7 = str2double(a7);

    %finding the lower coefficients 
    a8 = tline2(b(2)+4:b(3)+3);
    a8 = str2double(a8);
    a9= tline2(b(3)+4:b(4)+3);
    a9 = str2double(a9);
    a10 = tline2(b(4)+4:b(5)+3);
    a10 = str2double(a10);

    tline3 = fgetl(f1);
    c = strfind(tline3,'E');
    a11 = tline3(1:c(1)+3);
    a11 = str2double(a11);
    a12 = tline3(c(1)+4:c(2)+3);
    a12 = str2double(a12);
    a13 = tline3(c(2)+4:c(3)+3);
    a13 = str2double(a13);
    a14 = tline3(c(3)+4:c(4)+3);
    a14 = str2double(a14);

    %calculating specific heat 
    cp = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid);
    
    %calculating Entropy 
    S = Entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,T,R,tempmid);

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

    %calculating the molecular weight of the species 
    w = Molecular_weight(species);

    %Writing molecular weight file 
    MW_file = fopen('molecular weight.txt','w');
    fprintf(MW_file,'molecular weightof %s is %d',species,w);
    %closing the file 
    fclose(MW_file);

    %plotting cp, H, and s with the temperature 
    %saving in a folder 
    %changing the directory 
    
    %creating the directory 
    mkdir(species)
    cd(species)

    plot(T,cp)  
    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(S,T)
    figure(2)
    plot(T,S,'linewidth',2,'color','b');
    xlabel('Temperature(k)');
    ylabel('Entropy(kj/mol-k)');
    title(sprintf('Entropy vs Temperature range of %s',species));
    grid on 
    saveas(figure(2),'Entropy.jpg');

    plot(H,T)
    figure(3)
    plot(T,H,'linewidth',2,'color','b');
    xlabel('Temperature(k)');
    ylabel('Enthalpy(kj/mol-k)');
    title(sprintf('Enthalpy vs Temperature range of %s',species));
    grid on 
    saveas(figure(2),'Enthalpy.jpg');

    %changing directory to original matlab path
    cd ..

    % Molecular weight
    W = Molecular_weight(species);
end

  







    
    





    

• Firstly we input the parameters 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 temperature using strsplit command to convert it into cell array and then we will convert this string into 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 run the loop to find 53 elements in the data file by assigning the fgetl command and then spliting into the cell array to find the species lines and find the species name and then find the number of temperatures in the species line.
• Then we read the 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 coefficient then we will find remaining 14 coefficient and convert them to numbers from strings.
• Out of which we will find the first 7 coefficient which are for higher temperatures and then second 7 coefficient which are for lower temperatures.
• Now we will specify specific heat cp, entropy s, enthalpy H function 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.
• Now we will write the molecular weight.txt file and fprintf all the molecular weights of the species. And then close the text 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, heat , entropy and enthalpy with the temperature for different species.we will use scanf command to the title command to create dofferent species title.
• Then we will use saveas command to save the plots of different species in the directory folder. Now we will change the dorectory to which our main code file runs in the matlab.

Function to find specific heat :-

function cp = specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,T,R,tempmid)
%claculating 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) + (a12*(T).^4));
else
     cp = R*(a1 + (a2*T) + (a3*(T).^2) + (a4*(T).^3) + (a5*(T).^4));
end
end

STEPS :-

• Now we will find the specific heat by creating specific heat function and assigning its related formula coefficient from 14 coefficient,gas constant, temperature and mid temperature.
• Now we will create a condition using if loop and make the temperature less then and equal to mid temperature to specify lower temperature coefficient in the formula
• Then we will use else condition to specify coefficient of higher temperature coefficient in the formula.
• 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 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

• Now we will find the entropy by creating the entropy function and assigning its related formula coefficient from 14 coefficiens, Gas constant,Temperature and mid temperature.
• Now we will create a condition using if loop and make the temperature less then and equal to mid temperature to specify lower temperature coefficient in the formula.
• Then we will use else condition to specify coefficient of higher temperature coefficient in the formula.
• Then end the loop and function to calculate entropy.

Function to find enthalpy:-

function H = Enthalpy(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,T,R,tempmid)

%calculating Enthalpy 
%calulating Enthalpy for higher and lower temperature respectively 

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 
end 

STEPS:-

• Now we will find the enthalpy by creating the enthalpy function and assigning its related formula coefficient from 14 coefficiens, Gas constant,Temperature and mid temperature.
• Now we will create a condition using if loop and make the temperature less then and equal to mid temperature to specify lower temperature coefficient in the formula.
• Then we will use else condition to specify coefficient of higher temperature coefficient in the formula.
• Then end the loop and function to calculate enthalpy.

Function to find the molecular weight of the different species :-

function W = Molecular_weight(species)

%defining the atomic weight of the species 
atomic_name = ['H','C','O','N','Ar'];

%defining the atomic masses of the main species 
atomic_weight = [1.008 12.011 15.999 14.007 39.948];

%molecular weight starting rate 
W = 0; 
%loop runs to the length of the species 
for i = 1:length(species)
    %loop runs to the length of the atomic names 
    for j = 1:length(atomic_name)
        %function to compare the 2 strings
        if strcmp(species(i),atomic_name(j))
            W = W + atomic_weight(j);
            position = j;
        end 
    end

    %now we find if there is more element in the species then incrementing
    %atomic weight of the species 
    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

• Firstly we create an molecular_weight functionw and assigning species input to that
• Then define the main element of all 53 species in an array atomic_name that are :- 'H','C','O',' N','Ar'.
• Then by taking above main elements we will create there atomic_weight array from any source like internet that are 1.008 12.011 15.999 14.007 39.948.
• Then we will assign molecular starting range W 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.
• Then we will create a condition using if condition and use strcmp command to compare the species and atomic_name string to calculate the molecular masses if by comparison both string found same then we will assign its molecular weight.
• Now we will string to the number using str2num command assign to n. Then run an condition of if loop to find weither the species contains more then one element if there are more then one element that is n>1 then we will increase the atomic weight by the multiplication of position and n-1 to the atomic weight array.
• Then we will print the molecular weight using fprintf command and display it using disp command.

Errors:-

The error i faced in the programming is about spelling mistake of Str2double instead of str2double and i corrected the mistake.

Final results:-

plots:-

plots of species o2:-

Plots of species N2:-

Plots of species c02:-

Screenshot of the directory where different species are saved:-

Output of the molecular weight of the different species :-

Reference:-

1)https://www.mathworks.com/help/matlab/ref/deblank.html
2)https://www.mathworks.com/help/matlab/ref/mkdir.html?
searchhighlight=mkdir&s_tid=doc_srchtitle
3)https://www.mathworks.com/help/matlab/ref/cd.html