16.3.6 Using the Diesel Unsteady Laminar Flamelet Model

The diesel unsteady laminar flamelet model can only be enabled when conditions for compression-ignition are met:

• The Transient solver is selected in the General task page.

• The In-Cylinder dynamic mesh is enabled.

• The Discrete Phase model option Interaction with Continuous Phase is on.

A detailed chemical mechanism is required which should contain kinetic reactions appropriate for compression ignition. The mechanism can include pollutant formation reactions as well if you are interested in modeling emissions.

In the Chemistry tab, select Diesel Unsteady Flamelet.

Figure 16.3.3: The Enabled Diesel Unsteady Flamelet Model

With the Diesel Unsteady Flamelet model enabled, you can define the stream compositions (Section  16.4) and the flamelet controls (Section  16.5.2). Note that while you can enter the Number of Grid Points in Flamelet in the Flamelet tab (Section  16.6.2), you will not be able to calculate the flamelet or PDF table (Section  16.7). The reason for this is because the table creation and the flamelet calculation are performed at every time step of the ANSYS FLUENT simulation, and not just in a pre-processing step as in other non-premixed combustion models. However, you can set the table parameters in the Table tab.