Project 1 - Parsing NASA thermodynamic data
Aim:-Write a function that extracts the 14 coefficients and calculates the enthalpy, entropy and specific heats for all the species in the data file.File NASA thermodynamic data.
The formulae are shown below.
Here R is the universal gas constant, T is the temperature.
The FIRST 7 coefficients are HIGH-temperature coefficients and the SECOND 7 coefficients are LOW-temperature coefficients.
Objective:-
1. Calculate the molecular weight of each species and display it in the command window.
2. Plot the Cp, Enthalpy, and Entropy for the local temperature range (low temperature : high temperature) specific for each species.
The logic used behind code:-
In the given equation only seven coefficient were writesn but there are 14 coeffiecnt in Therm.dat file
so i have created Cp, H and S equation for other seven coeffiecien.
which are
Cp/R = a8 + a9 T + a10 T^2 + a11 T^3 + a12 T^4
H/RT = a8 + a9 T /2 + a10 T^2 /3 + a11 T^3 /4 + a12 T^4 /5 + a13/T
S/R = a8 lnT + a10 T + a11 T^2 /2 + a12 T^3 /3 + a13 T^4 /4 + a14
function used in code:-
1- To read a file "fopen" command has been used.
2- fgetl-read the file line by line.
3- strsplit:- Split string or character vector at the specified delimiter.
4- str2num:- Convert string into a number
5-currentfile: Identify current file
6-mkdir: creat new folder with species name
7-cd: change the current folder for the next species
The logic used to extract the local temperature and coefficients that.
1- identify any repeating element from the string and get the position by using "strfind" command.
2- After getting position converts the string into number and apply after and before numeric addition logic to calculate the coefficient.
3- above logic has to be applied for each line and all coefficients get extracted.
4- Applied the logic from 1-4 for all species using 'for' loop.
Code to create a function for Specific heat
function cp=specific_heat(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,temp,R,Local_mid_temp)
%cp=(a1+a2*T+a3*T^2+a4*T^3+a5*T^4)*R
T=temp;
if T>Local_mid_temp
cp=(a1+(a2.*T)+(a3.*T.^2)+(a4.*T.^3)+(a5.*T.^4)).*R;
else
cp=(a8+(a9.*T.^2)+(a10.*T.^3)+(a11.*T.^4)+(a12.*T.^5)).*R;
end
Code to create a function for Entropy
function S=entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,temp,R,Local_mid_temp)
%S=(a1*lnT+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)*R
T=temp;
if T>Local_mid_temp
S=((a1.*log(T))+(a2.*T)+((a3.*T.^2)/2)+((a4.*T.^3)/3)+((a5.*T.^4)/4)+a7)*R;
else
S=((a8.*log(T))+(a9.*T)+((a10.*T.^2)/2)+((a11.*T.^3)/3)+((a12.*T.^4)/4)+a14)*R;
endCode to create a function for Enthalpy
function S=entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,temp,R,Local_mid_temp)
%S=(a1*lnT+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)*R
T=temp;
if T>Local_mid_temp
S=((a1.*log(T))+(a2.*T)+((a3.*T.^2)/2)+((a4.*T.^3)/3)+((a5.*T.^4)/4)+a7)*R;
else
S=((a8.*log(T))+(a9.*T)+((a10.*T.^2)/2)+((a11.*T.^3)/3)+((a12.*T.^4)/4)+a14)*R;
endCode to create a function for Molecular weight
function [M]=molecular_weight(Species_name)
% Molecules=Name
Name=['H','O','N','C','A'];
standard_weight=[1.007,15.999,14.006,12.0096,39.792];
fprintf("molecular weight of ")
fprintf(Species_name)
fprintf(":")
M=0; % intitial molecular wt.
for i=1:length(Species_name);
for j=1:length(Name);
if strcmp(Species_name(i),Name(j));
M=M+standard_weight(j);
g=j;
end
end
n=str2num(Species_name(i));
if n>1;
M=M+standard_weight(g)*(n-1);
end
end
end
Main body code
clear all
close all
clc
% code to calculate the Cp,H,S and M values for diffrent species from
% nasa.therm file
% taotal specied 53
% calulate the moleculer weight for 53 species and store the plot
f1=fopen('THERMO.txt','r')
fgetl(f1);
global_temp=fgetl(f1); % reading of first line
x=strsplit(global_temp,' '); % spliting of string
global_localtemp=str2num(x{2}); % converting string to number
global_midtemp=str2num(x{3});
global_hightemp=str2num(x{4});
fgetl(f1); % reading second line
fgetl(f1); % reading third line
fgetl(f1); % reading fourth line
R=8.314 %universal gas constant J/mol-K
for i=1:53 % iteration to access the local temp and coefficient for 53 species.
line0=fgetl(f1); % reading line 5 i.e first line for the species
y=strfind(line0,'.'); % find '.' form the string
A=strsplit(line0); % Split the string as find string consider the single value
Species_name=(A{1}); % store the individual species
% to find the local temp
t1=line0(49:y(1)+3);
Local_min_temp=str2num(t1);
t2=line0(y(1)+6:y(2)+3);
Local_max_temp=str2num(t2);
t3=line0(y(2)+6:y(3)+3);
Local_mid_temp=str2num(t3);
%local coefficient
% hight temp coefficient
line1=fgetl(f1); %line 2 from the same species
a=strfind(line1,'.');
a1=line1(1:a(1)+12);
a1=str2num(a1);
a2=line1((a1)+13:a(2)+12);
a2=str2num(a2);
a3=line1(a(2)+13:a(3)+12);
a3=str2num(a3);
a4=line1(a(3)+13:a(4)+12);
a4=str2num(a4);
a5=line1(a(4)+13:a(5)+12);
a5=str2num(a5);
line2=fgetl(f1) ; %line third from the same species
b=strfind(line2,'.');
a6=line2(1:b(1)+12);
a6=str2num(a6);
a7=line2(b(1)+13:b(2)+12);
a7=str2num(a7);
% low temperature coefficient
a8=line2(b(2)+13:b(3)+12);
a8=str2num(a8);
a9=line2(b(3)+13:b(4)+12);
a9=str2num(a9);
a10=line2(b(4)+13:b(5)+12);
a10=str2num(a10);
line3=fgetl(f1) ; %line fourth for the same species
c=strfind(line3,'.');
a11=line3(1:c(1)+12);
a11=str2num(a11);
a12=line3(c(1)+13:c(2)+12);
a12=str2num(a12);
a13=line3(c(2)+13:c(3)+12);
a13=str2num(a13);
a14=line3(c(3)+13:c(4)+12);
a14=str2num(a14); % total fourteen coefficient calculated for a speciies
% local teamp range
temp=linspace(Local_min_temp,Local_max_temp,1000);
% function calling for specific heat
%Speciifc heat:%cp=(a1+a2*T+a3*T^2+a4*T^3+a5*T^4)*R
cp=specific_heat(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,temp,R,Local_mid_temp);
% function calling for enthalpy
% enthalpy H=(a1+a2*T/2+a3*T^2/3+a4*T^3/4+a5*T^4/5+a6/T)*R*T
H=enthalpy(a1,a2,a3,a4,a5,a6,a8,a9,a10,a11,a12,a13,temp,R,Local_mid_temp);
% function calling for Entropy
%Entropy S=(a1*lnT+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)*R
S=entropy(a1,a2,a3,a4,a5,a7,a8,a9,a10,a11,a12,a14,temp,R,Local_mid_temp);
% function calling for moleculer weight
%molecular weight
M=molecular_weight(Species_name)
% storing the values in diffrent file in directory
currentfile=pwd; % Identify current file
mkdir(Species_name); % creat new folder with species name
cd(Species_name); %change the current folder for next species
% plot of temp vs Specifie heat
figure(1);
plot(temp,cp,'linewidth',2,'color','b')
xlabel("Temperature[K]")
ylabel("Specific Heat [J/Kg.K]")
title("Temp Vs Specific Heat of Species")
% save the fig in directory
saveas(figure(1),'Specificheat.jpg')
% plot of temp vs Enthalpy
figure(2);
plot(temp,H,'linewidth',2,'color','r')
xlabel("Temperature[K]")
ylabel("Enthalpy [J/Kg.K]")
title("Temp Vs Enthalpy of Species")
% save the fig in directory
saveas(figure(2),'Enthaply.jpg')
% plot of temp Vs Entropy
figure(3)
plot(temp,S,'linewidth',2,'color','g')
xlabel("Temperature[K]")
ylabel("Entropy [J/Kg.K]")
title("Temp Vs Entropy of Species")
% save the fig in directory
saveas(figure(3),'Entropy.jpg')
%save the plot in current file
cd(currentfile)
endPLot for O2
PLOT for N2
PLot for CO2
Error faced :
1- Was not able to calculat the dia and tri atomic moleculer weight
the error i was getting because function value i specified as M and in for loop wt.
After taking help from Skill lync techical support person i was able to identify the error.
2- I was not able to identify the local temp because i gave written in the cammand windo y=strfind(line0,'G');
the output i was getting rendum .then after cunsulting with technical support person i was able to fin the local teamp using y=strfind(line0,' .');
3- I was getting issue to plot the specific heat and teamp, entropy & temp
The random plot i was getting .Then i find that the equation are missing . operation in multiplication and division.
Also i have written ln in place of log.
Species weight and folder location added in attachements.
References used.