Gaseq has been around since for some years and I'm afraid its interface still has a Windows 3.1 look to it. New features have been added over the years, but the Help file is still a little incomplete. Gaseq can be used on any 32 bit Windows system: 95, 98, NT, ME and 2000 and XP.
Now programmed using COM rather than the obsolete DDE. I have taken advantage of the increased capabilities of the programming method to plot a graph of the results of Auto-incremented calculations. An X-Y plot is generated with the X being the first property specified (usually the incremented one) and the others appearing as many Ys. Two Y scales are used: concentrations (mole fractions) are plotted on a log scale and the other properties, e.g. temperature, on a linear one. It is very difficult to provide a graphing facility which meets all requirements and it is inevitable that it will usually be necessary to edit of the graph within Excel to improve its appearance and utility. There have been difficulties with the Excel interface when using the later versions of Excel, but I hope the current Gaseq version (later than 28 July 2001) has put these right.
You can use any species in a thermodynamic calculation if you have its elemental composition, its enthalpy and entropy at 298K and its specific heat (Cp) at various temperatures. Only a single polynomial is fitted (the standard NASA form used two temperature ranges) so that the facility is useful for species which are significant only at low temperatures. This covers most organic molecules, but for new high temperature inorganic species you will have to use a more sophisticated method. It is also possible to make a database entry for a "fuel" by entering is elemental composition and its heat of combustion. You can then use it as a reactant in a combustion calculation, but clearly it cannot be used as a product.
Reactants with different
Each reactant species can have a different temperature. The average temperature of an unreating mixture can be calculated using the "UniformT" button if required ( an otherwise tedious calculation), but this is done automatically before most equilibrium calculations.
Specify product concentrations
When one or more product species reacts too slowly to be part of an equilibrium, this facility allows the equilibrium among the rest of the mixture to be calculated.
It is particularly useful for soot, which is present above equilibrium in some rich flames.
Specify the number of moles of
This is to handle "super-equilibrium" concentration of radicals which occur just after the reaction zone in low and moderate presssure flames. The reactions which interchange radical species (H, OH, O, etc.) are fast and equilibrated, but the recombination reactions which remove radicals are slow. The former do not change the number of species but the latter do, allowing a radical overshoot to be modelled.
Use mass units
Species concentrations can be entered and displayed in mass units. The reactants and products boxes change to a lurid blue colour to remind you that you have changed from a chemist into an engineer and are not using molar units.
Calculate viscosities and thermal
The thermal conductivities for diatomic and polyatomic molecules calculated are low by about 10% compared with those calculated by CHEMKIN using the online transport properties calculator. This is probably because the Mixture-Averaged method is used rather than the more rigorous Multicomponent formulation.
The folder which contains Gaseq.exe can now be read only, and a "local" folder is used to store any files generated by the user. This is set by clicking "Set local folder" on the File menu. The initialization file Gaseq.ini is no longer used and the settings for the program (such as the thermodynamic data files used and the window sizes) are stored separately for each user in the Registry. These changes are to facilitate sharing of the program on a network.
Use with an external program without a user interface (Blind mode)
The blind mode is mentioned in the Help file, but only if you know where to look, and then rather briefly.
Run an example problem in Gaseq and save as a .eq file. This can act as an input file as well, and can do so without much of the data.
Edit the eq file and Open it from Gaseq to make sure that you have left sufficient information for it to Calculate properly. This is not as logical as it should be; missing out some things confuses the parsing. For adiabatic and compression temperature calculations you need to provide a very rough estimate. See here for an example cut-down data file.
Your external program will need to write a file with this format and then call Gaseq with a command line:
Gaseq /e filename.eq
You will need to ensure that Gaseq is on your executables Path, that the filename is sufficiently specified and maybe that you have quotes around file names containing spaces. These are just normal DOS requirements. You can test it from Start/Run if you get this right.
The file will be updated to the full result of the calculation, and you will have to parse it to extract the information you require.
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