Project 1 - Parsing NASA thermodynamic data

PROJECT-1

AIM

Write a function that extracts 14 coefficents from 'NASA'S THERMODYNAMIC DATA' and calculate

1. ENTHALPY
2. ENTROPY
3. SPECIFIC HEAT
4. MOLECULAR WEIGHT OF EACH SPECIES
5. PLOT THE CP,ENTHALPY ,ENTROPY, FOR LOCAL TEMPARATURE RANGE

THEORY INVOLVED

FILE PARSING :

It is a method used to retrive information from a particular text or file and how that can be used in another program

NASAS THERMODYNAMIC FILE

THERMO.dat file is a data file containing 14 coefficients for 53 different elements given by NASA. These coefficients are utilized to calculate the specific heat, enthalpy & entropy for a particular element. Each element has its own range of local temperature.

NASAS POLYNOMIALS HAVE THE FORM

Cp/R = a1 + a2 T + a3 T^2 + a4 T^3 + a5 T^4

H/RT = a1 + a2 T /2 + a3 T^2 /3 + a4 T^3 /4 + a5 T^4 /5 + a6/T

S/R = a1 lnT + a2 T + a3 T^2 /2 + a4 T^3 /3 + a5 T^4 /4 + a7

where R is the universal gas constant whose value is 8.314 j/mol/k

T is the temparature , a1,a2,a3,a4,a5,a6,a7 are the numerical coefficents provided in thermo.dat file.

The first 7 coefficents are High- temparature coefficents (above 1000k) and second 7 coefficents are LOW-temparature coefficents (below 1000k)

CODING FUNCTIONS

function-1 , ENTHALPY

function[H]=enthalpy_H(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,temp,t_mid,R)
% first 7 temp are high and second 7 are low 
if(temp<=t_mid)
    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
end

function-2, SPECIFIC HEAT

function[cp]=specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,t_mid,temp,R)
% first 7 high temp coeff and next 7 low temp coiff
%temparature coefficients
if(temp<=t_mid)
    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
end

function-3, ENTROPY

function[s]=entropy_s(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,t_mid,temp,R)
if(temp<=t_mid)
    s=(a8*log(temp)+(a9*temp)+(a10*(temp.^2)/2)+(a11*(temp.^3)/3)+(a12*(temp.^4)/4)+(a14))*R;
else
     s=(a1*log(temp)+(a2*temp)+(a3*(temp.^2)/2)+(a4*(temp.^3)/3)+(a5*(temp.^4)/4)+(a7))*R;
end
end

figure-4, Molecular weight

% function to calculate molecular mass 
function mw=mol_wt(sp_name)

% storing values
compound_name=(sp_name);

% creating an array of elements 
key_at=['C','H','O','N','A'];
 
% storing molecular mass of individual element 
value_at=[12.0107 1.00794 15.994 14.0067 39.948];
 
% assigning molecular mass as zero 
mw=0;
% creating loop 
for i =1:length(compound_name)
for j=1:length(key_at)
     
    % comparing string value 
    if strcmp(compound_name(i),key_at(j))
        % if the comp is true mol mass is calculated 
        mw=mw+value_at(j);
        % storing the position for further use 
        pos=j;
    end
end
% converting the string to number 
k=str2num(compound_name(i));
 if (k>1)
     % molecular mass calculation 
     mw-mw+value_at(pos)*(k-1);
 end
end
fprintf('molecular weight of the species %s is %f',compound_name,mw)
end

MAIN PROGRAM

clear all
close all
clc
% file parsing_NASA thermodynamic data 

% opening of file 
f1=fopen('thermo.dat','r');

% skipping first five lines 
for i=1:5
    fgetl(f1);
end

% defining universal gas constant 
R=8.314;

% storing of species 
for i =1:53
    tline=fgetl(f1);
    A=strsplit(tline,' ');
    species=A{1};
    
    % temparature array 
    t_low=str2num(A{end-3});
    t_high=str2num(A{end-2});
    t_mid=str2num(A{end-1});
temp=linspace(t_low,t_high,500);

% finding coefficients
tline1=fgetl(f1)
pos1=findstr(tline1,'E');
%higher coefficents
% line 1 
a1=str2num(tline1(1:pos1(1)+3));
a2=str2num(tline1(pos1(1)+4:pos1(2)+3));
a3=str2num(tline1(pos1(2)+4:pos1(3)+3));
a4=str2num(tline1(pos1(3)+4:pos1(4)+3));
a5=str2num(tline1(pos1(4)+4:pos1(5)+3));

% line 2 
tline2=fgetl(f1);
pos2=findstr(tline2,'E');
a6=str2num(tline2(1:pos2(1)+3));
a7=str2num(tline2(pos2(1)+4:pos2(2)+3));
a8=str2num(tline2(pos2(2)+4:pos2(3)+3));
a9=str2num(tline2(pos2(3)+4:pos2(4)+3));
a10=str2num(tline2(pos2(4)+4:pos2(5)+3));

% line3
tline3=fgetl(f1);
pos3=findstr(tline3,'E')
a11=str2num(tline3(1:pos3(1)+3));
a12=str2num(tline3(pos3(1)+4:pos3(2)+3));
a13=str2num(tline3(pos3(2)+4:pos3(3)+3));
a14=str2num(tline3(pos3(3)+4:pos3(4)+3));

% specific heat 
cp=specific_heat(a1,a2,a3,a4,a5,a8,a9,a10,a11,a12,t_mid,temp,R);

% enthalpy 
H=enthalpy_H(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,temp,t_mid,R);

%entropy 
S=entropy_s(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,t_mid,temp,R);

% creating new folder for species 
mkdir(species)
% changing directory 
cd(species)

% plotting 
figure(1)

plot(temp,cp)
xlabel('Temparature')
ylabel('specific_heat')
title('cp vs temparature of',sprintf('%s',species))
saveas(figure(1),'cp vs T.jpg')
    
figure(2)
plot(temp,H)
xlabel('Temparature')
ylabel('Enthalpy')
title('Enthalpy vs Temparature of',sprintf('%s',species))
saveas(figure(2),'H vs T.jpg')

figure(3)
plot(temp,S)
xlabel('Temparature')
ylabel('Entropy')
title('Entropy vs Temparature of',sprintf('%s',species))
saveas(figure(3),'s vs T.jpg')
% coming back to program directory 
cd ..
    %calculating molecular weight of species 
M=mol_wt(species);
end

EXPLANATION OF THE PROGRAM

• function for Enthalpy : in order to calculate the enthalpy of each species we create a function for enthalpy , in step 1 all the inputs are defined sicnce we have high temparature coefficent and low temparature coefficent we use if condition .
• function for specific heat : in order to calculate the specific heat of each species we create a function for specifc_heat , in step 1 all the inputs are defined sicnce we have high temparature coefficent and low temparature coefficent we use if condition .

• function for ENTROPY : in order to calculate the entropy of each species we create a function for entropy , in step 1 all the inputs are defined sicnce we have high temparature coefficent and low temparature coefficent we use if condition .

• function for MOLECULAR WEIGHT :

1. in step one a function is created named as mol_wt
2. the name of species is stored in a variable called compound_name
3. an array of basic elements is created
4. the molecular weight of individual elements is created
5. strcmp is string comparison command used to compare values of compound_name and key_at if the two matches molecular weight is calculated
6. str2num command is used to convert a string into number

EXPLANATION OF MAIN PROGRAM

• fopen is a keyword used to open a file and and file name and permission is given as input
• fgetl is a command used to read first line and following subsequent lines
• using a for loop first 5 lines are skipped
• the value of universal gas constant is defined
• a second for loop is created from 1:53
• strsplit is a command used to remove spaces and split individual strings
• str2num is a command used to change the string value into numerical value
• temparature range is specified using a linspace command
• findstr is a command used to get string position value
• using findstr position of string E is found and is used find a1,a2,a3,a4,a5 from line 1
• similarly the position value of E is found at line 2 and is used to find a6,a7,a8,a9,a10
• the position value of E is calculated in line 3 and a11,a12,a13,a14 is calculated
• function of specific heat is called
• function of enthalpy is called
• function of entropy is called
• mkdir is a command used to create a new directory
• cd is a command used to change working directory

plotting

• figure 1- a plot is created for temparature vs specific heat ,save as ('name'.jpg) is a command used to save the plot as an image
• figure 2- a plot is created for temparature vs enthalpy ,save as ('name'.jpg) is used to save it as an image
• figure 3 - a plot is created for temparature vs entropy ,save as ('name.jpg') is used to save it as an image

PLOTS & IMAGES

figure-1 ( screen shot of window with all the saved folders)

figure-2 ( plots of O2)

figure-3 ( plots of N2)

figure-4 (plots of co2)

figure-5 ( molecular weight of all species)

ERRORS

1)

error in defining input variable T was replaced as temp since it is used everywere

2)

error occured due to usage of wrong brackets it is replaced by curly-brackets to remove error

RESULT

• molecular weight of each species is calculated
• 14 co-efficents are successfuly extracted and Enthalpy ,Entropy ,Specific heat of each species is calculated
• plots are made and saved as images
• project helped to study method of file parsing in detail

REFERENCES

https://en.wikipedia.org/wiki/Parsing

https://www.mathworks.com/matlabcentral/answers/106320-make-a-loop-to-calculate-molecular-weight

https://www.mathworks.com/matlabcentral/answers/317006-create-new-folders-by-mkdir