Perfectly stirred reactor model

[veerasekar sethuraman]

Hi users,

    

I'm part of the Cantera user group and working on a steady-state Perfectly Stirred Reactor (PSR) project. The goal is to model a combustion chamber where premixed mixtures (Methane + air) enters at 300K and 1 bar pressure. To calculate the adiabatic flame temperature and exit mixture composition, I'm using Python with the ZeroD ideal gas constant pressure reactor source model which uses species and energy equation.cpp file attached for your reference and python file attached

The PSR model doesn't require an ignition source, and the reactant temperature needn't exceed the autoignition temperature.However, I'm encountering an issue at an inlet temperature of 300K, the reactor's output temperature remains the same as the inlet temperature.

I need guidance on modifying the ideal gas constant pressure reactor source code to function accurately at the 300K inlet temperature. As the CVODES solver procedure is hidden, I lack initial conditions for the differential equations. Alternatively, I'm open to exploring the use of non-linear algebraic equations for species and energy equations, assuming steady-state conditions in the PSR.

I am interested in learning about the inclusion of the extensible reactor class in Python. I understand that this is a known concept, and I believe you have practical experience using it. Could you please provide me with information about it and offer a solution?

Thanks in advance

[Ray Speth]

Hi,

A PSR in this configuration can have one or more steady-state solutions depending on the residence time. For the range of mass flow rates where there are multiple solutions, the steady-state solution found by integrating the time-dependent problem, as done by Cantera, will depend on the initial conditions. 

This behavior is demonstrated in the example combustor.py. For cases where you are mostly interested in the strongly-reacting solution, this example shows the recommended practice of using the equilibrium condition as the initial condition. If you want a deeper understanding, this behavior should be covered in almost any introductory combustion textbook.

Regards,

Ray