How do you calculate the unburnt char in a CFX coal combustion calculation?
Please start the calculation with the option Output Control -> Results -> Extra Output Variables List and choose one variable for every Particle group you defined. Please choose any variable but Volume Fraction. This option activates an internal hook to write the mass flow variable of the particle tracks into the result file. You can evaluate the mass flow of the particles within your domain similar to the Eulerian phase variables.
In ANSYS CFX please do the following (assuming HC Fuel as particle material name):
` generate an Expression CharMassflowCalc = HC Fuel.Mass Flow * HC Fuel.Char.Mass Fraction
` generate a variable referencing the Expression: Char Mass flow = CharMassflowCalc
` create a plane where you want to calculate the massflow
o bound the plane if necessary (Plane definition -> Geometry tab -> Plane Bounds). You can set the center of the bounding box if the plane is set by three points. The first point specifies the center.
` sum up the variable Char Mass flow over the plane: sum(Char Mass flow)@plane 1
To evaluate the char for a specific burner inlet please see Solution 652949 - Post-processing of Unburnt Char in CFX 11.0 Coal Combustion Calculation