FlameModelling

From SYSOS

Simple Geometry

Consider the geometry shown in the figure below.

Figure1.JPG

Three files can be used to simulate the response of this system.

  • simsimplegeometry.m contains all parameters and executes the simulation.
  • sfunsimplegeometry.m contains the S-function (for more details on how to write S-functions in MALTAB see MATLAB's user guide). There is a line in this code for switching between time-varying and fixed delays.
  • mdlsimplegeometry.mdl is the SIMULINK file.

For analyzing the results, and to find the mean over time, meanovtime.m is used.

Using these files, the response for omega = 160rad/s for the cases of fixed and time-varying delays is:

Fixed delay, omega = 160 rad/s.
Time-Varying delay, omega = 160 rad/s.

More Complicated Geometry

Consider now the more complicated geometry shown below.

Figure2.JPG

For this case, we have the following MATLAB files.

  • simcomplexgeometry.m contains all parameters and executes the simulation. This saves everything in a .mat file which can be called by showsimresult.m (see below).
  • sfuncomplexgeometry.m contains the S-function (for more details on how to write S-functions in MALTAB see MATLAB's user guide). There are several changes that can be made, e.g., one can allow for different equivalence ratios at different radial positions at the entry point, etc.
  • mdlcomplexgeometry.mdl is the SIMULINK file.
  • showsimresult.m takes the mat file that was produced in simcomplexgeometry and animates the flame.

Apart from the meanovtime.m file, the newer version of MATLAB does not have a file I used in the above simulations:

  • vec.m reshapes a matrix into a vector by stacking its columns.