A sensitivity study of Lagrangian models for application to annular two-phase flows

Drop deposition in two-phase annular flow has been modeled with Lagrangian particle tracking using the CFD code CFX-11. The results are sensitive to the drop diameter, gas velocity and the density ratio. For air/water flows at atmospheric pressure the results agree reasonably with measurements. For helium/water flows the deposition seems to approach zero at fully developed conditions and for high pressure steam/water flows (BWR conditions) the simulated deposition coefficient is an order of magnitude higher than the experimental value. The discrepancies between predictions and measurements are analyzed and plausible reasons are discussed. (author)