17.3.1 Modifying the Constants for the Zimont Premixed Combustion Model

In general, you will not need to modify the constants used in the equations presented in this section in the separate Theory Guide. The default values are suitable for a wide range of premixed flames.

You can set the Turbulent Length Scale Constant ( $C_D$ in this equation in the separate Theory Guide), the Turbulent Flame Speed Constant ( $A$ in this equation ), the Stretch Factor Coefficient ( $\mu_{\rm str}$ in this equation ), the Turbulent Schmidt Number (Sc $_t$ in this equation ), and the Wall Damping Coefficient ( $\alpha_w$ in this equation ).

For a non-adiabatic premixed combustion model, note that the value you specify for the Turbulent Schmidt Number will also be used as the Prandtl number for energy. (The Energy Prandtl Number will therefore not appear in the Viscous Model dialog box for non-adiabatic premixed combustion models.) These parameters control the level of diffusion for the progress variable and for energy. Since the progress variable is closely related to energy (because the flame progress results in heat release), it is important that the transport equations use the same level of diffusion.