This repository contains a library of scripts to use the amazing thermochemical tool cpropep inside MATLAB scripts.
Easier than ever! Just download the files or clone the repo in your favorite folder. This repo also includes the executable, propellant data and thermochemical data.
Choosing the equilibrium solver with exit area ratio condition, the following code extracts the characteristic velocity of the combustion of an oxidant and a fuel with a set mass ratio.
mpropepPath = pwd; % mpropep initialization
mkdir .mpropep;
oxidantID = 657; % Dinitrogen monoxide
fuelID = 1032; % Paraffin
OFRatio = 7;
listPropellantID = [oxidantID fuelID];
listMass = [OFRatio 1];
writeInputFile(listPropellantID, listMass, 'EQ_AR', pressure, expansionRatio, '')
runComputation('', '', mpropepPath);
output = readOutputFile('');
characteristicVelocity = getParamFromOutput(propellantNumber, 'c*', 'EQ_AR', output);The cpropep.exe file is a command line utility that needs a configuration file, cpropep.conf, specifying the location of the list of propellant data propellant.dat and thermochemical quantities for the reaction computation thermo.dat.
The input file input.txt specifies the quantities of the compounds and the conditions under which to execute the computations. For further information read the file input_info.txt.
To run the program natively, open Command Prompt and move to the folder where cpropep.exe resides, for example:
c:\> cd c:\Users\user\Documents\GitHub\mpropep\cpropep
c:\Users\user\Documents\GitHub\mpropep\cpropep> cpropep.exe [-fopq]
To check if the program works, type:
> cpropep.exe -i
Thermo data file: thermo.dat
Propellant data file: propellant.dat
----------------------------------------------------------
Cpropep is [...]
Copyright (C) 2000 Antoine Lefebvre <[email protected]>
----------------------------------------------------------
The first two output lines show that the program found the two data files it needs and is ready to do some solving.
If the input file is named input.txt, the output of the utility will be displayed in the command prompt after typing:
> cpropep.exe -f input.txt
Thermo data file: thermo.dat
Propellant data file: propellant.dat
Computing case 1
[solver type]
Propellant composition
Code Name mol Mass (g) Composition
[ID1] ...... .... ....... ...........
[ID2] ...... .... ....... ...........
Density : ....
n different elements
.. .. .. .. .. ..
Total mass: ...
Enthalpy : ...
m possible gazeous species
p possible condensed species
CHAMBER THROAT EXIT
Pressure (atm) : .... .... ....
Temperature (K) : .... .... ....
[...]
Isp/g (s) : .... ....
Molar fractions
[compound1] .... .... ....
[compound2] .... .... ....
[compound3] .... .... ....
[...]
[compoundq] .... .... ....
In order to save the output to a text file output.txt you can write:
> cpropep.exe -f input.txt -o output.txt
The scripts developed in this repo make use of the command line interface by executing cpropep.exe inside MATLAB and via simple batch scripts.
In particular, the aim is to develop a system that seamlessly creates the input.txt file, runs the program with due flags, generates an output file output.txt and parses this output file to extract the desired results.
This library assumes the file list.txt, which contains the propellant list as interpreted by the utility, exists in the /cpropep/ folder and is up to date with the propellant.dat it was generated from. If you wish to edit propellant.dat by adding, removing, or editing some compounds remember to delete the list.txt file. This text file is used by the MATLAB scripts to infer the name of a compound given its identification number and is automatically updated by the library.
to be added
to be added