3. Multi-zone thermodynamic model

3.1 Two-zone model

The two-zone model represents the combustion phase more realistically than the single-zone model. The combustion chamber is divided into two distinct zones during this phase, with the zone separating the fresh and burnt gases resembling a flame front (figure 4 ).

The temperature in each zone is assumed to be uniform. While this temperature assumption is justified for fresh gases, it is questionable for burnt gases, since there is in fact a significant temperature gradient between the two zones. The composition in each zone is generally assumed to be constant for fresh gases, whereas burnt gases are considered to be in thermodynamic equilibrium....