Mass and Energy Imbalance in problems with DPM
When you check mass balance or energy balance in the : Report -> Fluxes panel for a problem where Discret phase is coupled to the gas phase, the user will get an uneven balance.
In DPM problems, the Report -> Fluxes panel will always give an uneven mass balance and energy balance. The energy imbalance being only for cases with combustion or heat transfer from the particles to the gas phase.
In this case the user should go to the Report -> Volume integral -> sum -> Discrete Phase Model, then calculate the sum for:
DPM mass source
DPM enthalpy source
the DPM mass source sum should be algebraically equal to the mass imbalance in the Report->flux panel
the DPM enthalpy source sun should be algebraically equal to the energy imbalance in the Report->flux panel
Of course, this happens at convergence. For large combustion problems, this energy balance can take longer to achieve and is a better indication of convergence than only relying on residuals.