2.1. Gas phase (CFD) The continuum gas field uses the existing Navier-Stokes equations in FULENT. In the coupling module, although two phases are created in FLUENT, the conservation equations for solid phase are not solved. The equation for conservation of mass, or continuity equation, can be written as follows: (1) The equation for conservation of momentum can be expressed as follows:
(2) Where , , and g are the gas density, gas velocity and gravity force vector, respectively. denotes the gas viscosity, and is the momentum sink. The coupling between the two phases is then achieved through the calculation of the momentum sink of the drag force that arises due to the relatively velocity between the phases. Therefore, the momentum sink S is calculated by (3) Where , and are control volume lengths, is fluid drag force which is explained in Section 2.2.
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