Inter-group mass transfer modeling in the two-group two-fluid model with interfacial area transport equation in condensing flow

Abstract

The two-group two-fluid model with interfacial area transport equation is analyzed in gas-dispersed condensing flow. Past work on the inter-group mass transfer model, required for closure of the dispersed phase conservation equations and interfacial area transport equations, has only considered the condition of expansion of group-1 bubbles to group-2 bubbles with inter-group transfer from group-2 to group-1 only through group-2 breakup. However, in condensing flows, the condensation of large group-2 bubbles provide a significant source of mass and interfacial area to group-1 bubbles. Therefore, the inter-group mass transfer model is revisited in this work to derive a more general form suitable to any heat transfer and pressure change condition. The resulting model requires a second inter-group transfer coefficient. In analogy to the original model, a general case of the group distributions is considered to describe a preliminary treatment of the new inter-group transfer coefficients. The simulation employs a coupled calculation of the void transport equations and interfacial area transport equations for both bubble groups. Validation against existing data shows results consistent with the physics of the flow field.